Ron RusayJanuary 8, 2004

Chem Bites Bytes: User-friendly ChemistryLiberal Arts / College Chemistry Textbook Proposal Chapter Draft: Food, Cooking & Nutrition

Chemistry topics covered in this chapter:

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Food, Cooking & NutritionFood for thought: “Are we what we eat?”

Energy is an intangible, abstract quantity that is rather difficult to appreciate since it can take many different forms such as wind, tides, sunlight, electricity, motion and heat. Thermal energy, heat, is the principal form of energy in chemical reactions. It is highly important, having served as the foundation of the industrial revolution by providing energy for machines to do work, and of our modern technological society by providing lighting, and running our computers and electronic devices. It is also the food of life for all living things, from humans to benthic creatures living at great ocean depths of more than a mile where no sunlight ever reaches and where pressure can crush all but specially designed man made diving vessels.

The thirst for energy can be insatiable. Animals, lions and bears for example, have an innate desire and ability to feast when food is in abundance and to store much of the energy for times of famine. How much energy have you eaten and stored today? Cooked foods appeal to our sense of taste, and the pleasing sensations that accompany eating appetizing foods easily distract from the idea that when we eat, we are actually filling our gas tank with fuel to produce energy. But, unlike our automobile, it is not as simple as burning the gasoline and having all of the reaction’s products exhausted out of the tail pipe. Our bodies have a complex collection of chemical processes that play important nutritional roles and like lions allow storage of unused energy as fat …just in case of a famine. But, obviously it is very unlikely that in our lifetime we will ever be confronted with a famine, although in poorly developed countries about 800 million people are undernourished and sizeable areas are struggling with drought, crop failures and famine. In many developed, affluent countries, as a result of less physical exercise, less personal need for energy but an everlasting innate desire to eat, obesity and being overweight have dramatically increased in the last twenty years. The World Health Organization (WHO) has coined the term “globesity” to describe the phenomenon. More than 60% of men and women in the United States are overweight with approximately half of those women are considered to be obese based on the Basal Metabolism Index’s (BMI) obesity threshold value of 30 (weight in kilograms divided by the person’s height in meters squared. A BMI in the range 25-29.9 is considered overweight.)

http://www.nhlbisupport.com/bmi/bmicalc.htm

Let’s examine two types of chemical reactions: synthesis and combustion as they relate to food, fuel, energy, humans and autos within a broad molecular, thermodynamic, and weight-conscious dietary context.

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Connections:The nucleus and the atom, Photosynthesis, Endothermic reactions, Carbon compounds, Energy, Thermodynamics, Catalysis, Enzymes, Anabolism, Combustion, Exothermic reactions, Catabolism

Chemical Skills:Conceptual understanding, Balancing equations, Mass and energy calculations, Drawing and interpreting energy diagrams, Drawing and recognizing structures and functions: lipids, fats, saccharides, proteins

Chemical links:Diet, nutrition, health, biological chemistry

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Professor Jacquelyn Barton, Cal Tech

Ron Rusay Copyright 2004 R.J. Rusay

Our sun is a star that is an energy factory. It has a climate with temperatures of many millions of degrees Celsius that produces energy by the nuclear fusion of isotopes of hydrogen: tritium and deuterium.

The sun’s energy that reaches the earth is in the form of electromagnetic radiation (light), which has visible (color) and invisible components such as infrared and ultraviolet radiation.

Have you ever burned the roof of your mouth with hot pizza? Why don’t your tongue and the bottom of your mouth burn?

Try an experiment. Take an ordinary kitchen thermometer and place it first in the top of a piece of pizza that has just been taken from the oven and then in the crust on the bottom. The temperatures should be the same.

Temperature therefore cannot explain why you burn the roof of your mouth and not the bottom. The concept of heat has to be used for an explanation.

There are several types of energy as we have seen, but there are two common energy units, the calorie and the joule, that are widely used. Scientists, governments and manufacturers should all use the international unit joule but the calorie is still employed by some. It was defined as the amount of energy (heat) that is necessary to raise 1 gram of water 1o Celsius from 14.5 oC to 15.5 oC. (One calorie is equal to 4.185 joules, but beware, the Calorie (Big C) on food packaging is actually a kilocalorie, 1,000 calories. 1 kilocalorie will raise 1 liter of water, about a quart, 1 oC or 1 gram of H2O 1,000 oC!).

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What is heat? What is the difference between temperature and thermal energy (heat)?

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Different materials have different capacities to absorb heat. Those with high capacities can absorb large amounts, such as water, which has one of the highest, whereas metals have some of the lowest. If you place a steel hammer and a very large pitcher of water of the same mass in the sun, eventually they will be at the same temperature, but the water has actually absorbed more heat than the hammer and requires more time to reach the temperature of the hammer.

A mathematical expression can be developed that relates the amount of heat, Q (joules, J) to the change in temperature T = T final – T initial (oC), the mass of the material (grams), and the specific heat of the material Cp (J/g • oC).

Q = Cp • mass • T

In a pizza, the top is mostly cheese which is high in water content, whereas the crust is relatively dry carbohydrate and protein which has a much lower heat capacity than the cheese and therefore has less energy although being at the same temperature, Qcheese > Qcrust. This is why only the roof of your mouth is burned.

It is absolutely essential for living organisms to capture and use energy. The critical importance of the sun was recognized by many ancient civilizations such as the Egyptians, Aztecs, Inca and the Mayans who practiced human blood sacrifice to sun gods as a religious rite. Fortunately for us, science has assisted in understanding that the sun does not require human fuel to keep its fires alive.

The marvel of capturing energy for life begins with photons of light striking the leaf surface of plants where the light is absorbed and enzymes in chlorophyll catalyze a complex series of reactions of two simple and plentiful molecules: water (H2O) and carbon dioxide (CO2).

Unlike the acidic effects of mixing CO2 with water that you saw in Chapter __, chlorophyll catalyzes the reaction to produce molecules of carbon (carbo-) and water

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How is solar energy captured? How is the energy released?

(hydrate), (CH2O)n, carbohydrates, where n= 3 or greater. Carbohydrates are also referred to as saccharides or sugars. These products have more energy in the form of new chemical bonds than the respective total of their starting materials (reactants). A simplified version of the reaction to form monosaccharides can be written as:

n CO2(g) + n H2O(g) + energy (CH2O) n (aq) + n O2(g)

However, oligo- and polysaccharides are a bit more complex, their molecular formulas are not the same as monosaccharides but do follow patterns that involve the base formulas of monosaccharides which combine and loose water.

Remember from Chap ___; mass must be conserved which means that the number of atoms for the different elements must balance, i.e., the reactants equal the products. Just as in mass conservation, energy must be conserved as well. This is the First Law of Thermodynamics.

A diagram illustrating the relative energy effects of the reaction can be drawn beginning with the starting materials:

In photosynthesis, carbon serves as an energy sponge that soaks up solar energy and stores it in the form of new chemical bonds in sugar molecules. There is a net increase in energy as the following diagram shows, the reaction is an endothermic reaction, energy is absorbed, E Reaction = (+).

(CH2O)n(aq) + n O2(g)

Note, without chlorophyll sugars are not produced. Chlorophyll serves as a catalyst. Catalysts lower the energy needed to initiate specific reactions by changing the reaction’s

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Energy

n CO2(g) + n H2O(g)

Energy

n CO2(g) + n H2O(g)

E Reaction = E Products – E Reactants

pathway but are unchanged themselves. This energy barrier/threshold is called the energy of activation, Ea.

(CH2O)n(aq) + n O2(g)

Animals feed on the plants, break molecular bonds through digestion and release stored energy in the form of heat through these chemical reactions (thermodynamics) much like the combustion of gasoline.

The balanced molecular formula equation for the combustion of octane, a key component of gasoline follows:

2 C8H18 + 25 O2 16 CO2 + 18 H2O + energy

Notice that energy is a product and not a reactant as in photosynthesis.

A diagram of the reaction follows. The reaction is an exothermic reaction. Energy has been released, E Reaction = (-), and although energy is released, an activation energy Ea, albeit very small, is still needed. This comes from the spark plugs in the engine.

Reactants2 C8H18 + 25 O2

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Energy

n CO2(g) + n H2O(g)

Ea = Uncatalyzed

Ea = Catalyzed

Energy

Products16 CO2 + 18 H2O

E Reaction = E Products – E Reactants

Ea

E Reaction

Reaction Path

The exothermic reactions associated with the digestion of sugars are catalyzed by enzymes, which can increase the rate of reaction by 1016 times over the uncatalyzed reaction. This is 10,000,000 billion times faster!

The overall molecular reaction can be pictured as:

(CH2O)n(aq) + n O2(g) n CO2(g) + n H2O(g) + energy

Notice the circle of chemistry that begins with the sun and photosynthesis. Many native cultures believe in the circle of life, which is similar to this cycle. When the system is in balance, which is described in some cultures as “harmony”, the amount of material and energy that is being produced is equal to the amounts that are being consumed, and the relative amounts of reactants and products that are present in your body or in a global ecosystem at anytime remain constant. The system is in dynamic equilibrium.

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Food Molecules: Carbohydrates, Fats, and Proteins

Enzymes, bio-molecular catalysts, occur in every organism. They include some that break down molecules (catabolism) and others that take small molecular pieces and use them to build other larger molecules (anabolism). Molecules that are built up include lipids, for example fats and the steroid cholesterol without which cells cannot survive, and structural proteins, tissue and muscle whose production are regulated by anabolic steroids. Metabolism is the combination of all biochemical processes, both anabolic and catabolic. Humans have approximately 30,000 proteins in their genome that control development and metabolism. Foods include proteins and fats as well as carbohydrates.

Nutrition focuses on among other things the energy produced from the catabolism of the three major types of molecules found in foods whose relative distribution varies widely. Meat is associated with fat and protein, plants (grains) with carbohydrates, but there are high fat fruits (eg. avocado) and high protein legumes (eg. soybeans). Fats produce about 9 Calories / gram versus about 5 Calories / gram for proteins and carbohydrates.

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oxidation and the release of energy

Fats Proteins

Fatty acidsand glycerol

Amino Acids

Small molecules

Anabolismof proteins

beakdown of larger molecules to smaller ones

Some nutrients and products of catabolism

Products of anabolism, including proteins and

nucleic acids

Catabolism Excretion

energy andreducing agents

Monosac-charides

Polysac-charides

ExcretionAnabolism

Catabolism Anabolism

In the U.S. over two decades, 1980-2000, the average Caloric intake per person increased from 2080 to 2347 Cal/day.

The percent energy breakdown for some different common foods are provided in the following table.

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Molecular formulas are insufficient to understand which bonds are broken and which are made in chemical reactions related to the processes. It is necessary to develop a different molecular view that has more information showing the way that the atoms are arranged (bonded) in the molecule. There are several possible types of drawings that structurally depict the arrangement based on the simple Lewis structures that you used in Chapter __. One type is the bond line drawing which is an extension of Lewis structures. Two other types are condensed formulas and line formulas.

The drawings provide essential information on the structural carbon backbone and chemical functionalities. Carbohydrates have alcohol functions, and may also have aldehyde, ketone and ether functions. Fats are esters that form from carboxylic acids and alcohols.

Condensed and line structures for normal octane, C8H18, follow. In the line drawing note the 8 carbons: 2 are at the termini of the chain and 1 at each angle. Hydrogens are not drawn.

CH3CH2CH2CH2CH2CH2CH2CH3

A single simple sugar unit is referred to as a monosaccharide such as the three illustrated below. They are capable of cyclizing and linking together. Sucrose is a disaccharide formed from one glucose and one fructose molecule. Almost everyone likes a sweet taste. Sugars are sweet. On a sweetness scale sucrose is rated 1.00. Its monosaccharides, glucose and fructose, are respectively rated 0.74 and 1.73. Look at a soft drink label and you will likely find fructose or high fructose corn syrup as the sweetener.

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What defines carbohydrates, fats and proteins on a structural level?

Bond line structures:

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Condensed + Line Structure:(Each point / angle in the structure is a carbon atom which must have four bonds. The missing number equals hydrogen atoms.)

Fats, triglycerides, are esters formed from glycerol, a tri-ol, and fatty acids, long chain acids that can be saturated, mono-unsaturated or polyunsaturated with cis or trans carbon-carbon double bond geometries that defines R-, R-, and R in the following reaction scheme.

“Saturation” relates to the maximum number of hydrogen atoms that are possible: single bonds versus double bonds.

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Unsaturated fats can have two possible bond arrangements about the carbon-carbon double bond: One with the hydrogen atoms on the same side, “cis”, and the other with the hydrogen atoms on opposite sides, “trans”.

CO2H

H

H

CO2HH H

Fats are categorized as lipids, which is a broad classification of bio-molecules that are not soluble in water, but dissolve in non-polar solvents like oil or gasoline. Fats are sensual. They provide a silky feel that comes from their molecular form tending to be round and smooth. They also enhance the taste of other foods, improve a person’s mood and are used to stabilize ice cream, which would be gritty and melt faster without fat. We will look at fats and their effects on arteries and the heart later in the chapter.

Another important lipid is cholesterol, structurally classified as a steroid. Our bodies naturally synthesize cholesterol using fatty acids as one of the starting materials. It is incorporated into cell walls and is essential to life. The amount in a person’s circulatory system depends on their diet and genetics. Cholesterol blood level (mg/dL) is used as an indicator of cardiovascular health and one’s susceptibility to heart disease. Lowering levels of cholesterol using a class of medicines called statins is a multi-billion dollar business for pharmaceutical companies. But like most things, taking statins on a daily basis has its own risk in possible toxic side effects to the liver among other effects. Steroids also serve as hormones and are important bio-regulators. Anabolic steroids are controlled substances with serious side effects that in males includes testicular cancer. A number of professional and amateur athletes have used them illegally to get an unfair edge over their competition. Several have been forced to return their Olympic medals.

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Proteins are the major components of muscle and tissue, and are also enzymes. They have peptide (amide) bonds that link amino acid units together which contain both an amine and carboxylic acid functions that are in their ionized forms since they react with each other.

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There are 22 amino acids that form the building blocks of proteins, 2 are common only to primitive bacteria and archeaea. They only differ by their respective side chains, R1 and R2 in the above illustration.

The above illustration is a portion of a protein, a hexapeptide that is formed from 6 different amino acids. Differences in the amino acids are highlighted in the colored side chains, which distinguish the six.

In the illustration, structures follow for the top amino acid, alanine, and the bottom amino acid, lysine, which are respectively:

O

O

HNH2

CH3

O

O

HNH2

CH2CH2CH2CH2NH2

The side chains are –CH3 and –CH2CH2CH2CH2NH2. Can you draw complete structures, identify the side chains and name the other four amino acids in the peptide?

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Diet and Nutrition

A strict herbivore would be a vegan, a carnivore a meat eater, but many humans are omnivores, eating both plants and animals. In developed countries, we have the privilege of choosing our diet.

Fundamental dietary issues are: 1) how much food energy (Calories) do you need to match your life style, and 2) is there a healthy balance in the nutritional components in your diet. Considering the number of obese and over weight people, these questions are either being avoided or not addressed by more than 3 out of every 5 people in the U.S.! A Food Pyramid provides guidance on dietary balance, but have you ever consulted it?

Food labels are regulated by the Food and Drug Administration (FDA). They include information that is tied to the dietary guidelines.

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What kind of –vore are you? Have you thought about your diet and nutrition?

The FDA has also approved guidelines that allow manufacturers to provide claims of their food products’ health benefits. However, the claims are categorized into four levels based on the soundness of the science that supports the claim, eg. calcium’s role in easing osteoporosis is ranked in the top tier with the highest confidence, whereas omega-3 fatty acids warding off heart disease is ranked with less confidence in the second tier but still significant.

Let us first look only at food Calories in general. A recent survey indicates that the average U.S. diet is about 2,350 Calories per day. This is enough energy to boil more than a gallon of water. Consider that an average size male has about 6 liters of blood (~ 1.5 gallons) and it requires about 66 Calories to raise the equivalent amount of water to the body’s temperature of 98.6 oF, where does all of the remaining energy go?

It goes to power the body’s chemical factories and maintain the body’s temperature and energy state. Even at rest, a person’s metabolic chemistry is working 24/7. Basal metabolism is the sum of all of the chemical reactions that occur when a person is at rest, without any demand from work or exercise. It is very unlikely that intellectual work is included in the definition, although it can take up a lot of Calories. Hmm…can thinking help in weight loss? Another food for thought is that only a few molecules ever reach the brain due to a barrier. Glucose does penetrate the barrier.

Food guidelines and food lablels use 2,000 Calories as a daily recommended value, but this is for an active individual of average size and weight and not estimated on minimum basal metabolic needs, which would be about 10- 20% lower. Also, be careful to look at the label since the values are not for the entire package but are typically given for 1 serving, which varies from product to product.

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Sugars, Saccharides, Starches

Everything that is eaten may sooner or later be converted to glucose. Simple sugars like sucrose (table sugar, corn syrup, honey) and those in pastries and white bread are quickly converted into glucose. Complex carbohydrates, polysaccharides or starches, are converted more slowly, and they typically do not provide the glucose spike or much less of one. A glycemic index was developed to help indicate which foods cause spikes in glucose levels. It was introduced in 1981. Since then, numerous scientific articles and commercial diet books have been published on the topic. However, the clinical, physiological significance of the glycemic index has remained debatable. A recent review by D.S. Ludwig, Journal of the American Medical Association (JAMA) 287(18):2414-23 (2002) broadly considers the glycemic index and its relevance to preventing and treating obesity, diabetes, and cardiovascular disease.

In your body the pancreas has cells that produce insulin, an enzyme that transports glucose from the bloodstream into cells where it is used for energy or stored as glycogen, a glucose polymer used for short term energy storage, or as a fat for long term storage.

There is a genetic, autoimmune disorder, Type I diabetes, where pancreas cells fail to produce enough insulin to process the glucose. It builds up to harmful levels in the blood and is found in urine which is an indicator of the disease and can lead to kidney failure, stroke, circulatory impairment, blindness and amputation. Individuals that are born with adequate insulin function may later in life develop diabetes. This used to be referred to as “adult onset diabetes”. It is now called Type II diabetes.

An estimated 200 million people have diabetes worldwide, and about 16 million people in the U.S. have Type II with an equal number having pre-diabetes, a condition that will

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Can there be too much of a good thing?

eventually lead to the Type II disease. The medical costs of diabetes and its related effects may be as high $100 billion!

Type II diabetes occurs when the pancreas has been overused and taxed to the point where it can no longer process all of the glucose in the blood.

This type of organ failure is common not only to the pancreas but to the liver as well, where catabolism of ethyl alcohol in chronic excessive alcohol drinkers leads to cirrhosis and liver failure. It appears that chemical factories in the body run down with chronic over use but unlike a real factory they cannot be repaired. The alternative is replacing the organ with a transplant, which if feasible is a most challenging and life threatening prospect.

Being overweight is a primary risk factor in Type II diabetes. Another factor is family history, particularly if parents and grandparents had the disease. Increase of the disease particularly in juveniles is alarming. The Centers for Disease Control (CDC) modeled the incidence and increase of Type II diabetes to predict that of those born in 2000 in the U.S. about 33% of Whites, 40% of Blacks and 50% of Hispanics will likely develop Type II diabetes in their lifetime based on current trends.

Insulin efficiency increases with weight reduction and exercise which are common therapies for diabetes and for a number of cardiovascular diseases. Diabetics are highly susceptible to these diseases and need to be aware and sensitive to their diet. Besides limiting Calorie intake and avoiding simple sugars, they also need to avoid fats particularly those highly implicated with circulatory impairment.

Fats

Fats are generally high energy molecules, 9 Cal/g, that are stored or produced, compared to 5 Cal/g for sugars and proteins. But aside from energy differences, there are other aspects of fats that are associated with the formation of arterial plaque, diminished circulatory capacity, high blood pressure, atherosclerosis, stroke, and heart attacks. Heart

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disease has been the number one killer in the U.S. and dietary fat has been a principal, controllable, causative factor.

As with carbohydrates, although all fats provide the same amount of energy per gram, they have differences based on their structure. Among them are thought to be the “Good, Bad and Ugly”. What molecular characteristics distinguish the three?

Saturated fats are considered to be potentially very harmful,”ugly”. As you saw, they have a much greater tendency to assume an overall round shape and to interact, “stick” to arterial walls and cause health problems.

Unsaturated fats are better, but there are differences in polyunsaturated (more than one carbon-carbon double bond) and mono-unsaturated as well as in the geometry of the bonds: cis- versus trans.

“Trans” fats are considered “bad” since they also stick but certain cis monounsaturated fats, having omega fatty acids that are found in fish oils are considered “good”.

Think of some physical properties of solids, hard and rigid, versus liquids that are fluid, moveable and tend to flow freely. Then think of a thick, oozy, sticky gel. These images can be used metaphorically for fatty acids and fats in your blood stream. The smaller the molar mass of the acid, the more like a liquid the material will be. For fatty acids that are found in fats they tend to be solids (the number of carbon atoms >12) and their glycerides tend to be sticky.

This description needs to be amplified since lipids actually wear protein coats and the denser the lipid plus protein coat, High Density Lipoprotein (HDL), the less likely that it will stick to arterial walls whereas Low Density Lipoprotein (LDL) does. A common misused reference relates HDL to “good” and LDL to “bad” cholesterol. There is only one cholesterol molecule, but it can wear different coats.

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Proteins

The body produces approximately the same amount of energy per gram of protein burned as per gram of carbohydrate, but carbohydrates and fats cannot provide the body with essential nitrogen, which proteins do through their amino acids. Animals produce 11 amino acids through the metabolism of proteins. The remaining 9 “essential” amino acids must be acquired through the diet. Lysine, an amino acid that you viewed structurally earlier in the chapter, is one of two essential amino acids that are present in only small amounts in plants. The other is tryptophan. Strict vegetarians must be sensitive to their diet to ensure that adequate amounts of both are included.

Proteins serve many functions, structurally in skin, hair and connective tissue and functionally in sugar regulation (insulin), in transporting other molecules like the oxygen that we breathe (hemoglobin), in digesting foods (trypsin) and in fighting off disease (antibodies).

Earlier in the chapter we saw that proteins are formed from amino acids into long, high molecular weight bio-polymers which range from about 6,000 to more than 1,000,000 daltons. (For bio-polymers, daltons (da) are used as the unit of molecular weight rather than molar mass (grams / mol) or atomic mass units (amu); 1 dalton = 1 amu). Insulin has a mass of 5,733 da with 51 amino acid residues, hemoglobin has 574 amino acids and a mass > 60,000 da.

Protein polymers assume two basic shapes: long, fiber-like strands that can intertwine (structural/contractile proteins) and globular, spherical masses (enzymes). The three strands of collagen are colored in the illustration shown below. It has a mass of > 2,000,000 da and a length of 1,000 nanometers which can stretch by approximately 3 fold. Do you know anyone who has had collagen injections for cosmetic reasons? A number of celebrities routinely have.

Trypsin, a protease, is one of several digestive enzymes that catalyze the breakdown of proteins through the hydrolysis of peptide bonds, which is the reverse of their formation. Another protease, papain, found in papaya is sold as Adolph’s meat tenderizer. Other proteases are found in pineapple and fresh kiwi fruit.

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The following animation shows a simplification of the process in which trypsin acts on a small molecule that contains an amide (peptide-like) bond. Three colored amino acids define the “active site” of the enzyme where the hydrolysis and bond breaking occurs followed by bond formation with water. A carboxylic acid and an amine are produced as the reaction products.

The QuickTime movie that accompanies the animation is an audio rendering of the amino acid sequence of trypsin. A musical note has been assigned to each of the 20 different amino acids that are found in the protein. See if you can use your auditory skills to identify human trypsin and mouse trypsin: http://ep.llnl.gov/msds/music/

Besides the fiber-like and globular gross features of proteins, which reflect their quaternary structure, there are three additional levels of structure that provide a detailed view.

Quaternary structure is the complete structure of a functional protein that includes all of its components.

Hemoglobin’s quaternary structure is shown below. It includes 4 chains, two identical -(alpha) chains with 141 amino acid residues each and two identical - (beta) chains with 146 amino acid residues plus a heme molecule in the center.

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A normal heme molecule has iron (Fe2+, green atom in the image below) coordinated to it that binds oxygen, which the protein carries throughout the body. In some people, instead of iron (Fe2+) they have (Fe3+), which does not bind oxygen as well causing thallesemia a type of genetic blood disease.

Iron is essential and small amounts are added to foods like cereal as dietary supplements. A simple experiment shows the amount isolated from a large bowl.

Protein function is critically dependent on the protein’s shape. Another genetic blood disorder, sickle cell anemia, is highly prevalent in Africa. It is genetically expressed in about 1 out of every 10 Black Americans, who have the sicklecell trait, and in about 1 out of 400, who have the disease. Although it is painful and debilitating, it does impart resistance to malaria. The disease is a result of abnormal hemoglobin which has 1 different amino acid in the - chain and results in the sickling of the red blood cells and a significant decrease in the transport of oxygen. Can you tell the difference between normal and sickle cell anemia from their musical renderings? See: http://ep.llnl.gov/msds/Columbia/slide10-3.html and previous slides from: http://ep.llnl.gov/msds/Columbia/slide8-3.html

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Tertiary structure is the overall 3-D shape of the protein. (Determined by all of the attractive and repulsive forces in the protein: hydrogen-bonding, dipole-dipole interactions, ionic bonds, covalent bonds and dispersion (London) forces).

Secondary structure is the arrangement of the various segments of the protein. (Determined by hydrogen bonding.) There are two fundamental types: - Alpha helix - Beta sheet

The above cartoon rendering of trypsin shows the 3- alpha helices in red and the beta sheets in yellow. (They were colored white and blue in the animation.)

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The alpha helix was first recognized by Linus Pauling in 1948. He was awarded the Nobel Prize in Chemistry in 1954 for his accomplishment and most remarkably was awarded a second Nobel Prize for Peace in 1963 for his activism, outspoken opposition to and organization of scientists against nuclear weapons. His advice was: "You can contribute, and you can't be sure how great your contribution is, but you can contribute, so do it."

Primary structure is the sequence of the amino acid residues in the protein chain.

The following two sequences are portions of the hemoglobin sequence for the normal and the sickle cell forms of the enzyme. Identify the amino acid in normal hemoglobin that is changed and the amino acid that it is changed to in the sickle cell form. Refer to Addendum 3 Table of Amino Acids.Normal: VHLTPEEKSASickle Cell: VHLTPVEKSA

There are about 30,000 proteins that are produced by the human genome and define a person, but each of us are constantly producing many, many more as antibodies in response to and in preparation for possible invasions of foreign materials from sources such as pathogenic bacteria and viruses. Each of us produce about 100 million different antibodies from mixing a library of 250, 10 and 6 possible contributors! These antibodies are not in direct response to antigens (foreign substances that the immune system reacts to ), but are being prepared preemptively in the event of something new and nasty comes along to challenge our system.

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Cooking and Taste

Energy is also at the core of cooking. Do you cook? What methods of energy transfer do you employ: boiling, grilling, frying, baking, steaming, microwaving, broiling, barbecueing ….. or letting someone else worry about it……as in convenience dining?

Heat is needed to break chemical bonds, to soften certain foods and to make them more digestible. Have you ever considered eating uncooked potato, rice or pasta? And, once cooked, which do you prefer: a soft, soggy boiled potato (without salt or butter) or a hot, crispy French fry?

Besides texture (remember the sensual fats), our eating pleasure is influenced by molecules that are associated with five fundamental tastes: sweet, sour, bitter, salty, and a recently recognized taste, umami, which is related to the effects of monosodium glutamate (MSG). Seasonings are also profoundly important. Your early childhood menu has imprinted your tastes and given you subtle preferences that last a lifetime. Are chili peppers too hot for your taste or can’t you live without them? The active ingredient capsaicin in hot peppers is used in topical over-the-counter ointments to treat pain, but as in a childhood diet, it takes a conditioning period in this case of several days before it actually provides relief. It irritates and burns quite a bit in the breaking-in phase.

Preparing food involves an enormous number of chemical reactions, heat control and the interactions of starches, sugars, fats and proteins. The challenge to a good cook is to produce tasty food that blends yet maintains the unique tastes of all of the chosen ingredients, yet to make it healthy and nutritious. This can be difficult in making good choices, for example, fried vs. boiled. Fried in what: oil, fat, butter? What kind of oil? Saturated? Hydrogenated (trans-unsaturated)? Unsaturated? By The Way: The FDA added the requirement of putting the amount of trans- fats on food labels to accompany total fat, % saturated and % unsaturated.

And, in boiling, say vegetables, what vitamins and minerals are lost when the water is discarded? Did iron go down the drain? What about food sensitivities? Lactose or gluten intolerance? Possible life threatening allergies from peanuts or almonds? Potentially embarrassing flatulence caused by difficult to digest sugars?

Who makes choices and selections for you? You or the cook at a fast food restaurant?

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Home experiment: First predict what you would expect the temperature difference in water to be in the following directions.

Slowly boil water on a stove, place a thermometer in it and record the temperature. Turn up the heat until the water boils rapidly and record the temperature.

Explain your observations and relate them to a boiled vs. fried potato.

Weight Loss, Dieting and Food Substitutes

Having choices is at the heart of everything, forms of government, foods and life. Some people have too few choices. Some have too many. Some choices are easy and others difficult. Some are made consciously, others unconsciously without apparent awareness. In many developed and developing countries where food is plentiful and manual work less and less necessary, poor unconscious choices in food and life style have led to an explosion of overweight people. More than half of the people in the US, England, Spain, Australia, France, Brazil, and Mexico are overweight.

Once recognized, one might think that it should be a simple matter for overweight people to shed unwanted excess weight, but it is not. A person has a complex system of bio-feedback mechanisms, and once weight is gained it is not so easy to loose it and keep it off since all of the mechanisms are set to maintain it. If it were as simple as a home’s thermostat, you could change the setting and almost instantly reset the energy state. However, think of a home with different rooms that require different temperatures, having separate temperature controls, and where some of the rooms are controlled by a mysterious, invisible person whose will cannot be overcome except with great determination and effort.

Some of the senses are heightened by eating. The thought of eating increases levels of the neurotransmitter dopamine in the brain, which is associated with pleasure. So eating is something people like to do, and to loose excess weight they have to first give up a portion of something that is naturally very pleasurable. So why diet?

Being overweight is considered to be the highest cause of death worldwide. Not from direct causes but from a large number of associated conditions particularly heart attack and stroke.

There are two simple, basic issues that control a normal person’s body weight: how many calories they eat and how much physical exercise they get. The second part of the equation is not pleasurable for most people. It takes effort and discipline to develop and practice exercise regimes that are frequent and rigorous enough to consume the excess stored energy in the body as fat, as well as giving up a bit of pleasure, reduced energy consumption…eating less food! In order to loose weight a person’s daily Calorie intake must be less than that is required by their basal metabolism.

Reducing Calories but not sacrificing the pleasure of eating, has generated opportunities for food and chemical companies. Do you drink diet cola, chew sugarless gum, put artificial sweetener in your coffee? In all of these cases, a chemical that tastes sweet but provides less overall Calories, since less of it can be used, has been substituted for natural or processed sugars. The leading artificial sweetener, aspartame, is 150-200x sweeter than sucrose. It is not a sugar but a dipeptide and was developed by Monsanto, a chemical company. It is widely used by food companies and produces billions of dollars of sales each year. Monsanto spun off the division to form a new company, Nutrasweet, which uses its name for the tradename of aspartame. By The Way: People who are sensitive or

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allergic to MSG most often have the same reaction to aspartame. Can you see why based on the comparison of their chemical structures?

Two other, common non-nutritional sweeteners are saccharin and cyclamates. You will find saccharin in coffee shop packets of Sweet ‘N Low, but you will have to go to Canada for cyclamates. It was withdrawn in the U.S. decades ago because eight out of 240 rats fed dose levels equivalent to humans ingesting 350 cans of diet soda per day had developed bladder tumors, so the FDA removed the product from the market. However, regulators in 50 countries including Canada decided that from the test data, the amount administered to the animals that had developed cancer was enormous, and unrealistic, equivalent to a human drinking cases of diet soft drinks per day. See: http://www.acsh.org/press/editorials/sweetener082699.html

Many new non-nutritive sweeteners with sweetness thousands of times greater than sucrose are on their way to market.

A fat substitute has also been developed. It took Procter & Gamble, an enormous, global food and household products company, 30 years of research and development and a very large financial investment to bring it to market. It is based on saccharides that are derived from corn and provides a silky sensation similar to natural fat but it is not digested so it provides no Calories. It is sold as Olestra and has been included in many products, but it has had a very shaky start since its launch in 1996. It effects a number of people’s gastrointestinal tract poorly and a label warning was required until recently when the FDA allowed it to be removed. The side effect is referred to as “anal oil leakage”! Will you give a bag of chips cooked in Olestra a try? It will cut out fat and reduce Calories, but at what risk?

Society seems to believe that there is a pill for everything, and a nice little drug would be a great diet/exercise substitute. Perhaps one day there may be, but the closest science has come so far has been the discovery of an enzyme, leptin, which is involved with metabolism and appetite. It seemed to offer great promise in controlling appetite and food intake. However, in a large test on rats, the results were very confusing. While a number lost weight, others showed no effects, and a significant number of test animals actuality gained enough weight to be considered obese!

There are many sources of help for people who want to loose weight. A plethora of self-help diet and exercise books have been published. WeightWatchers is one of many commercial enterprises that provide trainers who give personal diet and exercise advice as well as organizing support groups that help people to change their eating and life style habits and to maintain them over time.

Bland, high fiber, low fat diets have been the most common of all and were at their peak in the 1990s. However, they are giving way to a very popular, effective diet, the Atkins diet and variations of it. Dr. Atkins’ diet advice is quite different from the mainstream low fat, weak tasting fare.

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Dr. Atkins lived in New York City. He published several books on dieting over _ years. His audience grew with each new book and the diet has become one of the leading diets in the U.S. Subway sandwich shops even advertise “Atkins friendly” sandwiches. His latest book was released after his death. Dr. Atkins slipped on an icy patch outside of his apartment in the winter of 2003 causing a fatal injury at the height of his success.

If you purchase any medicine, either prescription or over the counter, the pharmaceutical company that manufactures it must provide product safety information that includes contraindications. These are the side effects that may occur from taking the drug. The next time you open a new box of aspirin, ibuprofen or acetaminophen don’t throw away the paper with the very small print before reading it. You will be very surprised at what it says might happen to you by taking the medicine.

Diet advice has no such requirement on publishing contraindications. Although effective in reducing body weight, there are risks attendant with Atkins’ recommendations, which are basically to eat a very high protein diet with a little fat and very, very little carbohydrate. One risk in following this advice is that very high protein diets can produce kidney stones that are too large to pass through the urethra, which is about 4 millimeters in diameter. When a person urinates, the stones block the passage causing excruciating pain, sometimes requiring surgery if they cannot eventually pass through the urethra.

A 16th century German-Swiss physician, Theophrastus Philippus Aureolus Bombastus von Paracelsus,(Paracelsus for short) is regarded as the founder of toxicology from his frequently quoted idea on poisons, which is loosely translated as “the dose is the poison”. Many things can be toxic in high concentrations including of all things water. A death certificate listed a suicide as death by water, not drowning. The victim intravenously administered a very large amount of water into their body wreaking havoc on their cellular chemical balance. Severely dehydrated people are not administered pure water but saline solutions to avoid cellular trauma caused by concentration imbalances.

Food, the brain and thinking are intimately tied together. The brain uses glucose in the blood for energy which comes mainly from daily diet. If a person fasts for long periods of time as is done in many religions, glucose blood levels are reduced dramatically which affects the brain’s available energy and the way a person thinks. Many people who fast feel good about their experience. However, taken to the extreme, starvation, the brain eventually finds a source of energy from a molecule that is catabolized from fat, and the brain and body decay, essentially feeding on themselves. Eating disorders like anorexia nervosa and bulimia can be debilitating and life threatening when the brain’s chemistry is altered disastrously affecting a person’s thinking and behavior.

Informed, wise choices, balance and moderation in food, eating and exercise can provide a healthy life, but can we make the necessary choices ourselves or do we need someone to give us a hand or even do it for us: the FDA, WeightWatchers, Dr. Atkins or perhaps even the Department of Homeland Security? Considering the percentage of people who are overweight and obese, there is an obvious and imminent national health threat.

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Could our eating habits and life styles unwittingly be supporting the long term aims of terrorism? Can fitness be related to patriotism?

End of Chapter Questions

1. Refer to the nuclear fusion animation at the beginning of the chapter. How many protons and neutrons are there respectively in each of the two reactants? How many are there respectively in each of the two products?

2. Since sunlight penetrates to only about 100 meters in the ocean and beyond that depth there is an absence of light but not life, how then can there be a well-developed community of animals at depths greater than one mile? (Hint: consider the energy attendant with geological processes.)

3. Animals who live on the earth’s surface generally live under a narrow regimen of temperature and pressure. A human’s nominal, normal body temperature is 36 oC (98.6 oF), but climate varies so that there are places on the planet with extremes that can be much greater than 36 oC (equatorial tropics) or much less than 36 oC (the polar ice caps). In order to inhabit these places man must adapt. Explain how man’s body adapts biologically to temperatures below 0 oC and above 36 oC, i.e. what happens with chemistry to stay warm and to cool? (Hint: consider the energy associated with physical change eg. boiling water, as well as that with chemical reactions.) How can a person adapt by other non-biological means? List three specific possibilities for each non-biological case.

4. Two containers of water are heated exactly the same way with a gas burner for exactly the same time. One container has 1 liter of water, the other has 2 liters. If the temperature in the 1 liter container increased 5.5 oC, how much did the temperature rise in the 2 liter container?

5. a) Is the following reaction endo- or exothermic? Briefly explain why?b) Complete the diagram with arrows showing an energy of activation without a catalyst and with a catalyst. Label all of the details of your illustration.

(Products)

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Energy

(Reactants)

E Reaction = E Products – E Reactants

6. Plant and animal carbonaceous materials have been converted to "crude oil" through microbial action and geochemical forces working over millions of years. The hydrocarbon "crude oil" that is pumped from underground and undersea deposits is processed into fuels ("fossil fuels") which are burned to release chemical energy for manufacturing, transportation and conversion into electricity.

Refer to the Web structures at: http://ep.llnl.gov/msds/Chem120/106shapesII-03.html The reaction below is the combustion (burning) of isooctane, an important component of gasoline.

a) Write a complete, balanced equation with molecular formulas for the combustion of isooctane.

b) Write a complete, balanced equation with molecular formulas for the photosynthesis of the -anomer of glucose, the cyclized form that is shown in one of the products of the reaction above.

c) Draw a bond line structure for isooctane.

d) Is isooctane saturated or unsaturated? Briefly explain.

e) Draw a condensed structure for n-octane (straight chain).

f) Draw a line structure for the -anomer of glucose, the product in the reaction.

g) The -anomer that is produced contains two different types of chemical functions. Circle them in your drawing in part (f) and identify them by name.

h) How many grams of pure CO2(g) would be needed to produce 100. g of glucose (about a quarter of a pound)? Show your calculation.

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i) What would be the volume of the CO2(g) in question (h) if it is at STP?

j) If 500 mL of CO2(g) were at 25 oC and 1 atm, what will be its final temperature if the mass is increased by adding 50% more CO2(g) and the pressure and volume are held constant? (Assume that it behaves ideally.) Explain in simple terms how might this question relate to global warming and energy demands.

6.

Group Challenge Problem:The complicated structure above is lipitor (“lipid regulator”), a leading statin to control cholesterol. The common, generic name is atvorvastatin. How many of each of the following atoms are in the molecule?

C ____H ____F ____ N ____ O ____ Ca ____

a. What is the molar mass of lipitor?b. How many moles of lipitor are there in an 80 mg dose? c. A synthetic pharmaceutical chemist reacted 0.055 moles of two reactants

to theoretically produce 0.055 moles of lipitor. She only isolated 63.9 g. What was her % yield? (%Yield = actual yield in grams / theoretical yield in grams x 100)

d. If she wanted to prepare 70. grams of lipitor how many moles of the starting materials should she use (presuming that her % yield would be the same)? Explain the basis for your answer.

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7. What two chemical functions are common to each of the following molecules?

O

O

HNH2

CH3

O

O

HNH2

CH2CH2CH2CH2NH2

8. a) Draw the structures for the amino acid in normal hemoglobin that is altered in sickle cell patients and the structure of the amino acid that it is altered to.

b) Draw structures for the two amino acids that are used to make aspartame. Consult: http://science.kennesaw.edu/~mhermes/nutra/nutra1c.htm

c) Complete the Chem Case:http://science.kennesaw.edu/~mhermes/nutra/nutra1c.htm

9. There are many possible drugs that are related to proteins. Most are administered by injection. Based on what you know and have read in this and previous chapters, do you think that it would be possible to take them orally? Explain. (The drugs must enter our blood stream chemically intact and have a certain shape in order to work pharmacologically. The pH of your stomach is approximately 2.)

10. In pan (A), 1000g of pure water was brought to a boil and used to cook 3 hard-boiled eggs. In a second pan (B), 125g of table salt was added to 1000g of pure water and brought to a boil. It was used to cook 3 hard-boiled eggs having the same total mass as those in the first pot. Circle all of the choices that you think are correct and briefly explain your reasons for those selected. (Refer to Chaps. __ and __ on boiling point and boiling point elevation.)

a) The temperature in pan A will be higher than B.b) The temperature in pan B will be higher than A.c) There will be more heat contained in pan A.d) There will be more heat contained in pan B.e) The eggs in both pans will cook to the same consistency in the same amount

of time.f) The eggs in pan A will cook faster than B.g) The eggs in pan B will cook faster than A.

11. As you saw in Chapter ___, C4H10, butane, has only two possible isomers; C5H10, pentane, has three. The number of isomers increases steadily with each additional carbon atom but it explodes with more than 10 carbon atoms. C11H24 has 4,347 possibilities and C12H26 366,319!

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The condensed and line drawings for straight chain, n-octane follow. Draw line drawings for three other different isomers of octane. Try to have the highest possible carbon-carbon bond branching in one of the three.

CH3CH2CH2CH2CH2CH2CH2CH3

For a refresher go to the previous Web exercise and structures at: http://ep.llnl.gov/msds/Chem120/106shapesII-03.html.

12. A student baked a frozen pizza in an oven set at 204 oC for 20 minutes. It was 28.5 cm in diameter and weighed 804 grams after baking; 177 grams was cheese. Using a digital laboratory thermometer the temperature of the cheese measured 89.5 oC and the crust 89.0 oC. The package contained six servings. Each serving had 11 grams of fat, 15 grams of protein and 39 grams of carbohydrate. The student quickly bit into a piece of the pizza and winced in pain. What does the piece of pizza that burned the roof of the student’s mouth contribute as a percent of recommended total daily Calories? How many pieces of pizza would meet the recommended daily total? Would a daily diet of only pizza be acceptable? Explain your reasoning.

13. The metabolic energy value of dietary lipids (fats and oils) is 9.0 Cal/g vs 5.0 Cal/g for proteins and carbohydrates. Calculate the energy that can be produced from 10 grams of the type of compound illustrated below. Express the value in SI units, joules (J). (Given: 4.184 J = 1 cal). If a person were attempting to maintain a daily intake of 2000 Calories, what percent of total Calories is this? Show your calculations. Do you think that eating this amount of this compound is OK for nutrition and general cardiovascular health? Briefly explain your reasoning.

14. Should a person who is following the Atkin’s diet include the following molecule as a major dietary component, minimize it or exclude it? Briefly explain.

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O2C

O2C

O2C

15. In the early 1990s the sales of popcorn in movie theaters plummeted after a newspaper article noted that movie popcorn was made with palm oil. Using the following table, briefly explain why you think people stopped eating popcorn and what oil you think the movie theaters might have switched to.

16. You have been assigned 3 partners. Assume that each of you has a body that is 70% water by mass.

A) Calculate the amount of energy in joules, calories and Calories needed to raise the temperature of the mass of water in the body of each of your group members from room temperature to its actual, hopefully "normal" temperature. Show your calculations. The specific heat of water is 4.184 J/g • oC and 4.184 J = 1 calorie.

B) Combustion of how many grams of sucrose, C12H22O11, would be required to maintain each person’s normal body temperature plus an additional 10% for the intellectual energy to complete this exercise? The heat produced per mole of sucrose is 5,640 kJ. Show your calculations. Report the total for the group to your instructor.

C) How many Calories would this amount to? How many grams of protein is this equivalent to? How many grams of fat is this equivalent to?

D) Refer to the chart from the Web page below, first estimate how many total Calories each member of the group uses per week. Then calculate how many Calories each of you are eating each week on average. Are you getting enough Calories or too many? Tabulate and total your results and report them to your instructor who will compile them.

Consult: http://www.westga.edu/~chem/courses/chem121s/121_06/sld048.htm

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17. Match the functions with their respective structural models. You may need to draw structures for some of the illustrated models first to recognize them.

Glucose ____ Glycerol ____ Lysine ____ Sucrose ____ Fatty Acid ____

cis-bond ____ trans-bond ____ Monosaccharide ____ Peptide ____ Trisaccharide ____

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Addendum 1/ Chem Bytes / Rusay Understanding Popcorn

http://www.popcorn.org/index.cfm

What's HappeningThe corn seed has a hard, dry skin that encloses an embryo which contains carbohydrates [nominally referred to as compounds with carbon + water]. When the seeds are heated, the water absorbs heat and boils [vaporizes: producing steam]. This creates a huge pressure inside the seed. When enough pressure is produced, the outer coat cracks ["pops"], the steam bursts out, and the seed turns inside out. The heat inside the shell cooks the carbohydrate before it actually pops to produce the characteristic white, fluffy pop corn.

Industry standards quantifying the characteristics and quality of popcorn:

ExpansionMWVT [Metric Weight Volumetric Test] is a measurement of expansion. It is expressed as cubic centimeters of popped corn per gram of pre-popped corn (cm3/g). [Not the unpopped "grannies".] It is the standard for the popcorn industry. The higher the number, the greater the volume of popped corn per weight of pre-popped corn.

Kernel Size Kernel size is measured as the number of kernels per 10 grams of corn [K/10g].

Moisture Content (Percent Water)Moisture level is critical for optimal popping. Depending on the variety, moisture content should be between 14% and 15%, that is, 14-15 g of H2O per 100 g popcorn (unpopped).

Using the measurement instruments discussed in class devise a general plan to generate the data (take measurements) for the above quantifiable characteristics of popcorn. You can work alone or in a group of 2-3. One sheet is to be turned in at the end of lab per group. Decide what instruments you plan to use and how will you use them. Advise Dr. R. who will follow your instructions. Observe the generation of the data and record it on the back of this page. Complete the table and be sure to include correct units for all values and clearly show how the, MWVT Number, Kernel Size and Percent Water were calculated.

______________________________________

Suggestions for further home experimentation:Further experiments can demonstrate the importance of the moisture inside the seed to the blast power of the corn; see what effect slowly drying the popcorn in a warm oven before popping has or try soaking the popcorn for one day before popping it. See also what affect cutting a deep scratch in the case of the seed has. What will happen with other graminaceae seeds: for example rice, oats and barley? Try microwaving them.

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Name(s)_______________________ Popcorn Brand Name _____________

Expansion & Kernel SizeMass of Popcorn (pre-popped)

Volume of Popcorn (popped)

MWVT number (cm3/g)

Number of Kernels

Mass of Kernels

Kernel Size (kernels/10g)

Percent Water (Moisture Content)Mass of Bag + Popcorn (pre-popped)

Mass of Bag + Popcorn (popped)

Mass of Water

Percent Water (g H2O/ 100g unpopped corn)

Calculations: MWVT Number:

Kernel Size:

Percent Water:

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Addendum 2/ Chem Bytes / RusayLaboratory Exercise

Carbohydrates, Digestion & EnzymesThe downside of eating high fiber, “healthy” foods (vegetables, grains. nuts, cereals):

gastrointestinal distress, Flatulence*

* Also known as passing gas, farting, flatus or breaking wind. Fart derives from the Latin word for "wind." "Flatulent" refers to being "liable to, or prolific in, windy blasts,"

http://www.etenet.com/Apps/Library/http://www.tipsofallsorts.com/flatus.html

___________________________________

Most people produce about O.5 liters to 1.5 liters of gas a day and everyone passes gas about 14 times a day on average. It is a natural, but usually unspeakable phenomenon that can occur at any time even when our bodies are relaxed while in bed or in the bathtub. How loud the sound of expelling gas is directly proportional to the volume and pressure of the gas. Some are silent.

It has been reported that it is unwise to withhold the urge to release gas since gas is absorbed into the blood stream and the liver can be overtaxed with recycled gas. However, many people think that they should not have any gas or what they do have needs to be reabsorbed and that any gas is too much.

Gas is made primarily of odorless vapors - carbon dioxide, nitrogen, hydrogen, and methane. The unpleasant odor of flatulence comes from anaerobic fermentation by bacteria in the colon. That "one-of-a-kind smell" comes from trace gases such as hydrogen sulfide, ammonia, indole, skatole putrecine and cadaverine that are produced by the person's unique gastrointestinal biota.

Although having gas is common, for most of us it is uncomfortable and embarrassing. The most common ways to reduce the discomfort of gas are changing diet, taking medicines, and reducing the amount of air one swallows.

Diet. A diet that is lactose-free may improve the condition as well as eliminating or reducing certain common gas-producing foods. (See the following table.) Doctors may also suggest limiting high-fat foods to reduce bloating and discomfort. This helps the stomach to empty faster, allowing gas to move into the small intestine.

Nonprescription medicines. Many nonprescription, over-the-counter medicines are available to help reduce symptoms, including antacids with simethicone and activated charcoal. The effectiveness of these medications is unclear. Digestive enzymes, such as lactase supplements, actually help digest carbohydrates and may allow people to eat foods that normally cause gas. Beano reduces gas production associated with baked beans and other types of foods which are rich in certain oligosaccharides (complex sugars called RFOs, the Raffinose Family of Oligosaccharides that are not digested in the human gastrointestinal tract. The product contains an enzyme which hydrolyzes the sugars into simpler forms, glucose and fructose, that are absorbed into the bloodstream which avoids their fermentation.

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http://www.beano.net/health_notes.htm#beans_ages

BEANS THROUGHOUT THE AGES

The next time you go to enjoy your favorite bean dish, know that there's a bushel of history behind it: Beans have been elevating mankind not just nutritionally but spiritually for thousands of years. Among the first crops ever cultivated, beans have helped people survive famines, had prominent families named after them, nourished centuries of sailors, and even had temples built in their honor as the symbols of life itself. Here's a closer look at some of the highlights in the long and glorious history of this noble nutritional mainstay.

* When our hunting-and-gathering prehistoric ancestors finally decided to stay in one place long enough to cultivate crops, beans were among the first to be grown.

* In the first Roman cookbook, written over 2,000 years ago, beans got an entire chapter

* The four most prominent families in ancient Rome named themselves after beans-the Lentulus (after lentils), the Fabius (after favas), the Ciceros (after chickpeas), and the Pisos (after peas).

* Beans were used as "ballots" by the ancient Greeks and Romans casting votes in political elections and legal trials.

* Christopher Columbus took chickpea seeds with him on his voyage to the Caribbean in the 15th century.

* In the 16th century, dried peas helped the peasant population of England survive a devastating famine.

* In the 17th century, beans were believed to be a cure for baldness. * In the early 1900s, nutritious beans were declared by President

Theodore Roosevelt as the reason for the US victory in the Battle of San Juan Hill.

* During World War II, the US Army floated waterproof bags of beans from ships to beachheads to help nourish American troops.

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Use 1 BEANO tablet or five drops of BEANO liquid per serving of problem food (one serving = 1/2 cup) with the first bite of food. A typical meal consists of two or three servings. For best results, you may have to adjust the number of tablets or drops according to your food portions. Too much heat can inactivate the enzyme, so don't cook with BEANO.

Foods Associated with Flatulence

Vegetables Legumes Grains/Cereals/Seeds/Nuts

Others

Beets Br

occoli Br

ussel sprouts C

abbage C

arrots C

auliflower C

orn C

ucumbers L

eeks L

ettuce O

nions

Black-eyed peas

Bog beans

Broad beans

Chickpeas

Field beans

Lentils

Lima beans

Mung beans

Peanuts

Peas

Pinto beans

Red kidney beans

Soybeans

Barley Bre

akfast cereals Gra

nola

Oat bran

Oat flour Pist

achios

Rice bran

Rye Ses

ame flour Sor

ghum, grain Sun

flower flour

Wheat bran

Whole wheat flour

Bagels

Baked beans

Bean salads

Chili

Lentil soup

Pasta

Peanut butter

Soy milk

Split-pea soup

Stir-fried vegetables

Stuffed cabbage

Tofu

Whole grain

breads

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The RFOs are fairly widespread in the plant kingdom, being found in many different families. RFOs rank second only to sucrose in abundance as water-soluble carbohydrates. A relatively high abundance of raffinose, stachyose and verbascose are found in the foods listed in the Table: Foods Associated with Flatulence.

The Raffinose Family of Oligosaccharides (RFOs) is comprised of -galactosyl derivatives of sucrose. The most common are: the trisaccharide raffinose, the tetrasaccharide stachyose and the pentasaccahride verbascose. Note that the RFOs are simply sucrose plus either one, two or three galactoses. The trisaccharide raffinose, O--D-galactopyranosyl-(1,6)- O--D-glucopyranosyl-(1,2)- -D-fructofuranoside, is composed of three monosaccharides in the following order: D-galactose-D-glucose-D-fructose (reading the structure upward). It can be considered as galactose + sucrose connected via an (1-6) glycosidic linkage, and so raffinose can be broken apart into galactose and sucrose via the enzyme -galactosidase. Humans and other monogastric animals (pigs and poultry) do not contain this enzyme.

The following enzymatic chart illustrates the RFO biochemical pathway.

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Experimental Background:

Stock solutions were prepared for each group of student researchers by soaking ~50g of raw RFO containing produce, which were selected from the Table: Foods Associated with Flatulence, with 100mL of deionized water at 25 oC for 12h. Each of these stock solutions serves as the initial stock substrate [S]o solution that will be diluted and incubated with active enzymes: -galactosidase and sucrase, which are contained in Beano. They produce glucose and fructose.

Oligosaccharides + H2O galactose + sucrose

Sucrose + H2O glucose + fructose

Instuctor Option 1:Have students read the following instructions, complete the data table and answer the questions that follow the procedure.

Procedure:

Check out a 5 mL pipet and (2)10mL volumetric flasks. Have a time keeping device available that can measure time in minutes. Using the stock solution that was assigned to your group pipet 5mL of the solution into a labeled glass vial, [S]o. Pipet a second 5mL aliquot into one of the volumetric flasks and dilute with deionized water to 10mL. Pipet 5mL of this diluted substrate solution into the second volumetric flask and dilute. Take the remaining 5mL of the first volumetric and place in a labeled vial: 0.5[S]o. Place the 10mL of the second volumetric in a labeled third vial, 0.25[S]o. Seal the vials with caps and place in a constant temperature water bath for 20-30 minutes at your assigned temperature. Using a micro syringe, add 10L of liquid Beano to each vial and record the time. Replace the vials in the constant temperature bath. Test one drop from each substrate vial every 5-10 minutes (recording the exact time) over a period of 40-50 minutes using the Glucometer Elite test strip and device. Record the readings.

At the end of the test period, add a few drops of 0.1M HCl(aq) to vial [S]o. Place the vial in the constant temperature bath for ~5min, then test and record the reading.

Glucometers are used by diabetics to monitor their blood sugar levels. They are designed and calibrated for blood chemistry, not for simple aqueous solutions. The Glucometer Elite measures the concentration of only the -anomer of D-glucose. A computer chip processes the input to determine the overall concentration of glucose. Therefore, using the aqueous calibration graph that follows, the Glucometer Elite data readings can be converted to respective concentrations of glucose. The calibration curve was generated using glucose solutions that were prepared 12h before analysis. During this period, there is a difference in the rates of mutarotation, which is the interconversion of - and -anomers. The system eventually comes to a balance when equilibrium is reached. Programming and building the chip requires that mutarotation and Keq be considered in producing the Glucometer Elite in order to obtain an accurate reading of glucose concentration in blood.

Using the Calibration Graph for water solutions, which follows, convert the Glucometer Elite data readings to respective concentrations of glucose. Graph glucose

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-galactosidase

sucrase

concentration versus time for each of the 3 substrate trials on the same graph, and answer the lab questions.

Instuctor Option 2:Have students use data sets that are provided: Flatulence: Beano-Enzyme Kinetics DataClass Data 5/6/03

         

Sugar Source Concentration Reading Temperature[S]o Glucometer

[S]o =100mL deionized H2O Extracts of 50g of producetime (min) (mg/dL) (oC)

(lo = below detection limit)         Split Green Peas 0.5[S]o 25

7 lo14 23124 26834 296

0.5[S]o 353 83

18 34528 37041 36363 360

+ 0.1M HCl25 83

0.5[S]o 357.5 226

16.25 28925 32835 283

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         Red Kidney Beans 0.5[S]o 25

3 3214 4117 5340 52

0.5[S]o 356 33

20 4940 5655 9465 57

         Lentils 0.25[S]o 35

9 4218 4827 4537 48

0.5[S]o 359 80

19 7828 6738 87

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Names _____________________ Chem Bytes / Rusay

FlatulenceCarbohydrates, Digestion & Enzymes

Data: X [S]o (CIRCLE ONE: X = 1; X = 0.5; X = 0.25)

Food: Temperature:

Time(min)

Glucometer Elite

ReadingGlucose Concentration

(mg/dL)

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Glucometer Elite Calibration

y = 1.5636x - 46.797

0

100

200

300

400

500

600

700

0 50 100 150 200 250 300 350 400 450Glucose Concentration mg/dL

Series1Linear (Series1)

Graph the three sets of data. Include complete information on the following graph: Title, Labels (with units) for the x and y axis, a Legend for the data sets and draw smooth curves for each of the data sets.

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Questions:

1. What chemical functions are present in sucrose?

2. Describe a key structural difference between D-glucose and D-fructose.

3. From the data, does the rate of RFO digestion using Beano depend on the concentration of sugar present? Explain how this relates to eating gas producing foods, the amount of gas produced, and how fast the gas is produced.

4. Do you think that Beano is just as effective in vivo as in these in vitro tests? Explain within the context of your experimental data, the stomach’s acidity and oral administration.

5. In your own words describe the difference between an -anomer and a -anomer. Explain how anomeric difference is very important in the interrelationship of termites-wood & humans-carbohydrates.

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6. A lab assistant was assigned the task of preparing the calibration graph used in this experiment, but forgot to wait 12 hours. Dr. R. noticed that the calibration data was incorrect and had the student redo the data but this time take data at 1h, 6h, 12h, 18h and 24h intervals. The data was compared. That taken at 12h, 18h and 24h were all the same, but the 1h and 6h data differed from all of the others. Explain what is occurring over the 24 hour period using the concepts of equilibrium relative to Keq.

7. What is the molecular formula of stachyose?

8. How many grams of galactose would be produced by complete hydrolysis of 5 mmol of stachyose? Show your calculation.

9. Assuming that each mol of galactose from the calculation in question 6) produces 1 mole of gas, which behaves Ideally, what would be the volume of gas produced? Assume STP, Standard Temperature & Pressure; show your calculation.

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10. Would Beano work if added to foods before cooking? Hint: estimate the optimum temperature for Beano performance. Explain your answer.

11. What effect would washing raw beans, discarding the water, and then cooking them have on the RFO concentration in the cooked beans? Explain your answer.

12. Use the following experimental, tabular data for different enzyme concentrations at constant oligosaccharide concentration, [E]o. Does the rate of RFO digestion using Beano depend on the concentration of the enzyme present? What would be the effect on gas production of doubling the amount of Beano taken? Provide a number for this effect (eg. 10% increase; 15% decrease, etc.) Explain the way that you arrived at your value.

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Temperature Effects

0

50

100

150

200

250

300

350

0 2 4 6 8 10 12 14 16Time (minutes)

Series1Series2Series325 oC80 oC90 oC

[E]o 0.4[E]o 0.1[E]oTime Glucose Glucose Glucose

min mg/dL mg/dL mg/dL

5 70 40 1515 175 75 4020 210 90 5030 245 125 70

Addendum 3/ Chem Bytes / Rusay

The Chemistry of Flour: Amino Acids & Proteins

Activity Goals: To study gluten formation and consider some factors and additives which can affect

gluten formation and dough’s elasticity, and apply these observations on a molecular level to amino acids and proteins.

Part I: Uniformly mix 3.0 ounces of flour with water (50% by weight) for each of the flour types

listed in Table 2, except for "Vital Gluten" which should be 75%. Table 2 is on the second page.

Roll each dough into a ball. Knead each of them for 1 minute and compare their relative

elasticity. Use Table 1 to compare the flours by recording the more elastic of the two, eg. Cake

Flour (Ca) vs. Bread (Br). Give each 1/2 for a tie. Total the number of times each flour was

selected. Enter the total under “Elasticity” in the second table and rank them 1 through 6.

TABLE 1:VG WW Ry Br AP

Ca

AP

Br

Ry

WW

Part II: Divide each dough ball into three approximately equal parts. Knead one portion of the

“Bread Flour” dough for an additional 2 minutes and record your observation. Take this portion

and one portion of each of the other doughs and place them on a baking sheet.

_________________________________________________

Web Resources:http://www.exploratorium.edu/cooking/bread/index.htmlhttp://www.recipesource.com/baked-goods/http://www.exploratorium.edu/cooking/bread/activity-gluten.html

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Then, for all of the flour doughs: Take a second portion and add 1/8 teaspoon of salt and knead

for 1 minute. To the last portion add 1/4 teaspoon of lemon juice and knead for 1 minute,

compare their relative elasticities to their elasticitiy before addition and record your

Observations / Conclusions. [Optional] Place all of the portions on the baking sheet in a pattern

that will allow you to easily compare their differences once baked. Place the sheet in an 350 oF

oven for 10-15 min. Record your observations in Table 3.

TABLE 2:Type of Flour Elasticity

(Ranking)Observations /Conclusions

(Salt)

Observations /Conclusions

(Lemon Juice)Cake (Ca)

All Purpose (AP)

Bread (Br)

Rye (Ry)

Whole Wheat (WW)

"Vital Gluten"(VG)

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TABLE 3: Observations after baking

Type of Flour PlainDough

Salt added

Lemon Juice

Added

Cake (Ca)

All Purpose (AP)

Bread (Br)

Rye (Ry)

Whole Wheat (WW)

"Vital Gluten"(VG)

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1) Define glutenin and gliadin. They have very few charged amino acids. Therefore, they are not very soluble in water. However, about 35-40% of the amino acid residues in them are glutamine. Using intermolecular chemical principles, briefly explain why the glutamine distribution can relate to flour interacting with water to form dough.

2) List the flours used in increasing order of gluten content and compare them to your ranking of the dough’s elasticity. Explain theoretically what chemical effects lemon juice and salt might have on the elasticity of dough.

3) What do you think is the correlation of dough elasticity is to: (a) highly hydrophilic amino acids and (b) hydrophobic amino acids?

4) Draw structures for the two amino acids that form the non-nutritive sweetener, “Aspartame”?

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Table of Amino Acids

NH2

R

R'CO2H

Amino Acids:

Name I II R- R’- RasmolColor

Function &Class

Alanine Ala A H- CH3- dark gray AliphaticHydrophobic

Arginine Arg R H--CH2CH2CH2NHCNH2

NH blue BasicHydrophilic

Asparagine Asn N H-

-CH2CNH2

O cyan AmideHighly

Hydrophilic

Aspartate Asp D H-

-CH2COH

O bright red AcidicHydrophilic

Cysteine Cys C H- -CH2SH yellow Sulphur Containing

HydrophobicGlutamine Gln Q H-

-CH2CH2CNH2

O cyan AmideHighly

HydrophilicGlutamate Glu E H-

-CH2CH2COH

O bright red AcidicHydrophilic

Glycine Gly G H- H- light gray AliphaticHydrophobic

Histidine His H H-N

N

H

CH2-

pale blue BasicHydrophilic

Isoleucine Ile I H-

-CHCH2CH3

CH3 green AliphaticHydrophobic

Leucine Leu L H--CH2CHCH3

CH3 green AliphaticHydrophobic

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Lysine Lys K H- -CH2CH2CH2CH2NH2 blue BasicHydrophilic

Methionine Met M H- -CH2CH2SCH3 yellow SulphurContaining

HydrophobicPhenyl-alanine

Phe F H- CH2- mid blue AromaticHydrophobic

Proline Pro P -N

H

CO2H

flesh AliphaticHydrophobic

Serine Ser S H- -CH2OH orange HydroxylicHydrophobic

Threonine Thr T H- -CHOH

CH3

orange HydroxylicHydrophobic

Tryptophan Trp W H-

NH

CH2-

pink AromaticHydrophobic

Tyrosine Tyr Y H-

OH

CH2- mid blue AromaticHydrophobic

Valine Val V H-

-CHCH3

CH3 green AliphaticHydrophobic

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Flour & the Action of Waterhttp://members.lycos.nl/ClassoFoods/ukindex.html

Wheat flour

The wheat grain consists of three main parts: the endosperm, the bran, which is mostly wall tissue and the wheat's germ. The germ is rich in oil and it contains lots of vitamins. The endosperm is where the starch is stored. It also houses the protein that transforms into gluten during kneading. The wall tissue encapsulates the endosperm. The wall is made from several layers. The aleuron layer separates the endosperm from these adjoining layers. The wall contains a significant amount of fibre.

The aleuron layer is also rich in proteins and vitamins. Wheat is ground to separate the endosperm from these wall layers and the germ. During the grinding the endosperm is reduced to what we know as flour, after grinding the wall layers and germ make up the bran portion.

The grinding is done in several stages. In order to have complete grinding the wheat kernel passes through 20 sets of rollers. The first 5 or 6 roller pairs are corrugated and serve to break the grains and to turn tiny chunks of endosperm into grist and bran particles. This part of the grinding is called crushing. After every passage the grits is sifted in sifters, where the flour is separated from the larger particles that need more grinding. In the course of the grinding process the more or less pure pieces of endosperm are reduced to flour by smooth rollers. The fraction of the wheat that is converted to flour is determined in this part of the process.

In theory flour is produced in every pass and sifting. Because of the 20 passes, there will be also 20 flour fractions that will differ in many aspects such as : the contents of the proteins, ash, and fibre. The fractions are commonly characterised by their ash content. Flour from the first passage has the lowest ash content. During the manufacture of a specific flour product from a mix of flours, the ash contents are used as a guideline. For instance the flour packaged as Blue Stem has a relatively high ash content. It is not from a species of wheat, but from a mixture of different varieties of wheat.

Whole wheat flour is made of the whole wheat grain, so the ash content is the same as that of wheat, about 1,8%. The ash content drops if the share of the wall layers in the grinding material diminishes. The lowest ash content is found in so called plain flour (0,46%). The inner part of the endosperm is the main constituent of plain flour. A higher degree of grinding goes along with a higher water up take. Most of the fibres end up in the remaining bran. Those fibres can absorb relative large amount of water. The protein content also increases with the degree of grinding. This is quite logical : the outer layers contain much more protein than the more internal layers. Especially in and directly underneath the aleuron layer one finds tissues with a very high protein content. This high protein content does unfortunately not improve the baking properties . The protein from the aleuronic doesn’t form gluten during the dough preparation and has consequently no contribution to the baking properties.

The wheat grain consists of about 8 to 15% of protein. The proteins are found enclosed between the starch grains. Wheat protein comes in a large variety of different molecules, with markedly divergent properties. The most import can be distinguished by their specific solvent :

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a. albumin : dissolves in water b. globulin : dissolves in salt solutions c. gliadin : dissolves in 70 % alcohol d. glutenin : dissolves in diluted acids or bases

The first two form about 20% of the total amount of protein, while the glutenine and gliadin contribution is the remaining 80 % . The latter are responsible for the formation of the gluten during kneading. The gliadin and glutenine form a network of molecules capable of holding the carbon-dioxide gas that is a by-product of fermentation. It is this network of lace that causes the bread to rise.

But the amount of protein present doesn’t reflect anything about its quality. The baker talks about baking properties of the flour. For example, a flour containing 12% protein, ground from European wheat will, in general, result in a flour with less baking quality, than a similar flour grind from American wheat having the same protein content. This different behaviour is mainly caused by the difference in wheat varieties grown in Europe and America.

In every day practice one always selects those varieties that are most suitable for a certain application. Flours having a low protein content or a bad protein quality are rarely used in bread preparation. These flours result in bread quality that falls below normal standards. They can be used in applications where the gluten development doesn’t play such an important role. What comes to mind are cookies or cakes. In those cases the baker often uses flour with a protein content of 10 % and below. For the preparation of most kinds of bread a flour with a protein content between 11 and 13% is used. For special applications like biscuits one uses flours with a protein content in the 15-16% range.

A number of substances improve the baking properties of the flour. They are called dough conditioners. The use of those dough conditioners makes the dough more substantial, the rise gets larger and the crumb structure gets finer. These substances normally reinforce the gluten network. The improvement of the dough properties is especially important in case of mechanical mixing and kneading. The larger volume and the finer crumb influence mainly the eating properties of the bread. It becomes softer and less crumby.

All flour improvers are oxidants i.e. they produce oxygen when mixed with water and when energy is added to the system (by the mixing). The oxygen in its turn reacts with protein in the flour. All the fine details of this chain reaction are still unknown. The action of the flour conditioners can be compared with what happens during storage of flour. It is a well-known fact that the baking properties of the flour improve when it is stored for some time after grinding. This is attributed to the oxidation of proteins by oxygen from the air. Nowadays flour is already used within one week after grinding, so it doesn’t get enough time to ripen. Moreover, the effect of natural oxidation is quite small compared to the action of dough conditioners. However, a too large dose causes a deeply advanced oxidation which makes the dough to stiff. It becomes overly unworkable.

In the past and especially in the USA potassium bromate (KBrO3) was used as oxidizer. It is the most effective substances of all the dough conditioners known. It gives the dough good working up properties and the bread a fine, soft and regular crumb. And it has a slow reaction. After kneading and even after the final prove a portion of the KBrO3 still not has reacted. Only during the baking is the bromate converted to bromide (KBr). This means that the potassium bromate is doing a part of its job during the ovenspring. Continuing to soften and elasticise the proteins. Stiff

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doughs have a good use in bakeries where Pullman style or rectangular loaves are produced. Ovenspring is assured by the use of the dough conditioners. Interestingly, it is mostly seen in use in the Netherlands and the Anglo-Saxon or English speaking countries. During the 1980s bromate and many of its compounds became suspected as health threatening and prohibition of the use of potassium-bromate followed.

In countries where hearth baked breads is the favourite kind of bread the baker uses ascorbic acid (vitamin C) as dough conditioner. It is totally harmless. Heat decomposes the ascorbic acid completely. During the baking of the bread all vitamin C is lost. The function of ascorbic acid is the same as any other, oxidizing the dough.

The gluten lace is formed through sulphur bridges. Too many S-S bridges makes the dough stiff and sturdy. In the dough thiol groups (SH) influence of the mobility of the protein molecules with respect to each other. This can be demonstrated by adding extra thiol groups in the form of cystein to the dough. The dough gets much more flabby. Oxidation removes thiol groups, two SH groups are converted to one SS group plus water. The mobility of the proteins decreases, thereby making the dough less pliable.

Ascorbic acid differs in one aspect from other dough conditioners. In itself is it not an oxidizer but a reducer. Its activity stems from a preceding reaction during kneading with oxygen in the air. It is than converted to dehydro-ascorbic acid and that is an oxidizer. When this substance oxidises the proteins it is reduced back to ascorbic acid. The formation of dehydro-ascorbic acid is only possible during the kneading. This is the only moment that oxygen from the air can be beaten into the dough. After the kneading the yeast consumes all the remaining oxygen, leaving none in the dough during the rise.

____________________________

Water

An essential element of any recipe, is water , the importance of which is very often overlooked. A bread dough is roughly 40 % water. In making dough, the consistency depends clearly on the amount of water used in making it. The amount of water needed depends on the quality of the flour and the kind of bread we want to make.

What is the purpose of water in bread making ? Water is needed to form the gluten and give the dough consistency. It is also the solvent or medium for substances like sugar and enzymes that are indispensable for the fermentation. The next essential role is its function in homogenizing all this substances throughout the dough during kneading. The water is also needed for swelling and gelatinisation of the starch. This in its turn improves the easy digestion of the bread. The distribution of the heat through the bread during baking is done by water in the dough. And finally water influences the organoleptic properties of the bread.

Besides the amount of water we are using, its quality plays also an important role.

The most important criteria for water is its hardness. This is a measure for the content of calcium and magnesium salts dissolved in the water. Water with a mild hardness is the most useful, because the mineral salts reinforce the gluten network. If the hardness is too high (more then 180 parts ppm or 180 mg per litre) the fermentation slows down because of the too rigid gluten structure. Using more yeast or adding malt to the dough are the best ways to correct this

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condition. In the opposite case, where water hardness is less then 120 ppm the dough gets sticky. In this case one has to use less water and although the consistency of the dough looks normal, one shouldn’t forget that such a dough retains less CO2 during rise. Bread gets the right volume, but the crumb structure will be shabby when one uses too soft (with low hardness) water. The softness and the keeping qualities are negatively influenced.

Another important factor is the pH of the water used. Acids are responsible for the flavour and the taste of the bread. The acids, necessary for a good organoleptic experience will be neutralized if the alkalinity becomes larger then a pH of 8. The activity of the yeast and lactic acid bacteria drops if their environment becomes alkaline. The enzymatic activity also suffers from a too high pH. Their optimal pH must be in the range 4.0 to 5.5, which is also excellent for the yeast and the lactic bacteria.

The use of too much water is not a suitable practice. The loaf will stay small and flat, the cells of the crumb will be too large, the crust stays pale and the crumb will be wet and not soft. The other error is too little water. The crust will get tough and the crumb dry.

__________________________________

Noël Haegensnoelhaegens@skynet.be

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