Chemistry of FoodChemistry of Food

Fresh baked breadFresh baked bread

Would you like some Would you like some butter on it?butter on it?

Or margarine?Or margarine? Or Benecol?Or Benecol? Or Smart Balance?Or Smart Balance?

LipidsLipids

Organic substance Organic substance found in living found in living systems that is not systems that is not soluble in watersoluble in water Fats & oils 95% of Fats & oils 95% of

lipids in diet are theselipids in diet are these Steroids Extremely Steroids Extremely

important in cell important in cell function, hormonesfunction, hormones

WaxesWaxes

Fats solidsFats solids Oils liquidsOils liquids

Lipids and HealthLipids and Health

Diets that are high in Diets that are high in saturated fats are saturated fats are associated with an associated with an increased risk of increased risk of coronary artery coronary artery diseasedisease

Saturated fatsSaturated fats

Found in animal derived fatsFound in animal derived fats Usually solidsUsually solids Butter is a saturated fat, also high in cholesterolButter is a saturated fat, also high in cholesterol

ciscis Unsaturated fats Unsaturated fats

Naturally occurring unsaturated fatNaturally occurring unsaturated fat Found in plant derived fatsFound in plant derived fats About 30% of our daily calories should be from fatAbout 30% of our daily calories should be from fat

TransTrans unsaturated fats unsaturated fats

Formed from hydrogenation of unsaturated fatsFormed from hydrogenation of unsaturated fats This is done to make the fat more solid, ex. Peanut This is done to make the fat more solid, ex. Peanut

butterbutter TFA associated with increased heart diseaseTFA associated with increased heart disease

MargarinesMargarines

Margarines do not have cholesterol, they are made from plant derived Margarines do not have cholesterol, they are made from plant derived fatty acids, originally unsaturatedfatty acids, originally unsaturated

To give them solid consistency, they are hydrogenated, resulting in To give them solid consistency, they are hydrogenated, resulting in trans fatty acids (TFA)trans fatty acids (TFA)

Can’t believe Can’t believe has 1g of TFA per 10 g total fat in 1T servinghas 1g of TFA per 10 g total fat in 1T serving Blue bonnet has 2 g of TFA per 7 g total fat in 1 T servingBlue bonnet has 2 g of TFA per 7 g total fat in 1 T serving

““Health” SpreadsHealth” Spreads

These spreads are made from unsaturated vegetable These spreads are made from unsaturated vegetable oils, no cholesterol, lower saturationoils, no cholesterol, lower saturation

Also do not have trans fatty acidsAlso do not have trans fatty acids Better for you?Better for you?

Fake fatsFake fats Olestra (Proctor & Olestra (Proctor &

Gamble)Gamble) Replaced glycerol with Replaced glycerol with

sucrose, 6 to 8 fatty acidssucrose, 6 to 8 fatty acids No calories, not digestedNo calories, not digested Removes oil soluble Removes oil soluble

vitamins & cartenoidsvitamins & cartenoids Severe gastrointestinal Severe gastrointestinal

problemsproblems

Carbohydrates Carbohydrates Good or Bad?Good or Bad?

CarbohydratesCarbohydrates

Carbohydrates: Hydrates of carbon Have Carbohydrates: Hydrates of carbon Have general formula: Cx(H2O)y in which x general formula: Cx(H2O)y in which x and y are whole numbersand y are whole numbers

Carbohydrates consist of:Carbohydrates consist of: MonosacchadridesMonosacchadrides DisaccharidesDisaccharides StarchStarch CelluloseCellulose

Carbohydrates in DietCarbohydrates in Diet

Typically half the Typically half the calories in the human calories in the human diet are made up of diet are made up of carbohydratescarbohydrates

The Atkins diet limits The Atkins diet limits the amount of the amount of carbohydrates in carbohydrates in your dietyour diet

MonosaccharidesMonosaccharides

What is the difference What is the difference between these between these sugars?sugars?

They are isomers of They are isomers of one another. one another. Isomer:Isomer: Same formula but Same formula but different arrangement different arrangement of the connectivity/ of the connectivity/ geometry of the geometry of the molecule.molecule.

DisaccharidesDisaccharides

These are 2 simple sugars These are 2 simple sugars combined together (with combined together (with elimination of 1 Helimination of 1 H22O)O)

General formula: CGeneral formula: C1212HH2222OO1111

Average daily Western Average daily Western consumption of simple consumption of simple sugars is 170gsugars is 170g

Density DemonstrationDensity Demonstration

Density = Mass/ VolumeDensity = Mass/ Volume The density of water is 1g/mLThe density of water is 1g/mL Why do the two kinds of pop behave Why do the two kinds of pop behave

differently?differently? Different densitiesDifferent densities Majority of both pops is composed of water Majority of both pops is composed of water

but the added sugar in the sweetened pop but the added sugar in the sweetened pop increases the density and causes it to sinkincreases the density and causes it to sink

Carbohydrates & HealthCarbohydrates & Health

Simple sugars are Simple sugars are responsible for dental responsible for dental cavitiescavities

Simple sugars Simple sugars contribute to obesitycontribute to obesity

Simple sugars are Simple sugars are thought to be thought to be important in the important in the development of Type development of Type II DiabetesII Diabetes

Artificial SweetenersArtificial Sweeteners

1

180

300

0

100

200

300

sugar aspartame saccharin

Relative Sweetness of Different Common Sweeteners

Saccharin: Not Saccharin: Not digested, no caloric digested, no caloric value, bitter aftertaste, value, bitter aftertaste, possible carcinogen, possible carcinogen, not used as muchnot used as much

Aspartame Aspartame (NutraSweet): Does (NutraSweet): Does have caloric value but have caloric value but more sweetness per more sweetness per gram than sucrosegram than sucrose

AspartameAspartame Decomposes10% per month at Decomposes10% per month at

room temperatureroom temperature How is rate affected by How is rate affected by

temperature?temperature? Increased Temp. Increased RateIncreased Temp. Increased Rate Cooking rapidly decomposes Cooking rapidly decomposes

NutraSweetNutraSweet

PolysaccharidesPolysaccharides

Consist of many Consist of many sugars bonded sugars bonded togethertogether

Polymer: A large Polymer: A large molecule with a molecule with a repeating unitrepeating unit

Common Common polysaccharides polysaccharides include: cellulose, include: cellulose, glycogen, and starchglycogen, and starch

Biomolecules GeometryBiomolecules Geometry

ChiralityChirality Chirality = Chirality =

HandednessHandedness Molecules that cannot Molecules that cannot

be superimposed on be superimposed on their mirror images are their mirror images are called chiral.called chiral.

Molecules that can be Molecules that can be superimposed on their superimposed on their mirror images are mirror images are achiralachiral

ChiralityChirality

Which of the following objects is chiral?Which of the following objects is chiral? A table knife, a pencil, a pair of gloves, a A table knife, a pencil, a pair of gloves, a

shirt that has buttons, a TV setshirt that has buttons, a TV set A table knife, a pencilA table knife, a pencil, , a pair of glovesa pair of gloves, , a a

shirt that has buttonsshirt that has buttons, , a TV seta TV set

ChiralityChirality

Enantiomers: Chiral pair of molecules, Enantiomers: Chiral pair of molecules, have same exact formula but are have same exact formula but are different moleculesdifferent molecules

Racemic: Equal portions of both Racemic: Equal portions of both enantiomersenantiomers

Examples: Aleve, thaliomide, ibuprofinExamples: Aleve, thaliomide, ibuprofin