Food Chemistry, part 1

Dr. ClowerCHEM 4201

Food Chemistry DefinitionDefinition Components of foodComponents of food Behavior of these componentsBehavior of these components Example:Example:

Ethanoic acidEthanoic acid -D-glucopyranosyl-(1,2)--D-glucopyranosyl-(1,2)--D-fructofuranose-D-fructofuranose pp-hydroxybenzyl and indoylmethyl -hydroxybenzyl and indoylmethyl

glucosinolatesglucosinolates SS-propenylcysteine sulfoxide-propenylcysteine sulfoxide -carotene-carotene phosphatidylcholinephosphatidylcholine

Components of Food Monosaccharides, Monosaccharides,

disaccharides, disaccharides, polysaccharidespolysaccharides

LipidsLipids ProteinsProteins VitaminsVitamins MineralsMinerals

ColorsColors FlavorsFlavors PreservativesPreservatives WaterWater Other Other

components components (caffeine, toxins, (caffeine, toxins, etc.) etc.)

Metabolic Pathways Anabolism and Anabolism and

catabolismcatabolism CarbohydratesCarbohydrates LipidsLipids Proteins (amino acids)Proteins (amino acids) NucleotidesNucleotides

All relate to citric acid All relate to citric acid cyclecycle

How does this relate How does this relate to nutrition?to nutrition? Molecules from outside Molecules from outside

the body (food)the body (food)

Nutrients DefinitionDefinition MacronutrientsMacronutrients

CarbohydratesCarbohydrates FatsFats ProteinsProteins

MicronutrientsMicronutrients MineralsMinerals VitaminsVitamins

Carbohydrates MonosaccharidMonosaccharid

eses DisaccharidesDisaccharides PolysaccharidePolysaccharide

ss FiberFiber RequirementsRequirements Artificial Artificial

sweetenerssweeteners

Fats SaturatedSaturated UnsaturatedUnsaturated Trans fatsTrans fats CholesterolCholesterol RequirementsRequirements

Linolenic acidLinoleic

acid

Protein Biological valueBiological value Nitrogen balanceNitrogen balance RequirementRequirement

Government Food Guides

Government Food Guides

USDA Food Guide Pyramid

Government Food Guides

And today…

Minerals Inorganic substancesInorganic substances CofactorsCofactors MacromineralsMacrominerals

Na, K, ClNa, K, Cl--, Mg, P, Mg, P CaCa

MicromineralsMicrominerals CrCr MnMn Cu, Zn, I, FeCu, Zn, I, Fe

Acrodermatitis enteropathicaAcrodermatitis enteropathica GoiterGoiter

FF

Vitamins Organic compoundsOrganic compounds Necessary for Necessary for

metabolic processesmetabolic processes Insufficient synthesis Insufficient synthesis

in the bodyin the body Recommended Daily Recommended Daily

ValuesValues Fat-solubleFat-soluble Water-solubleWater-soluble

Figure from Lippincott’s Biochemistry, 2nd ed., 1994

Vitamins Water-solubleWater-soluble

ThiamineThiamine RiboflavinRiboflavin NiacinNiacin PyridoxinePyridoxine BiotinBiotin Folic acidFolic acid CobalaminCobalamin Ascorbic acidAscorbic acid Pantothenic acidPantothenic acid

Fat-solubleFat-soluble Vitamin AVitamin A Vitamin DVitamin D Vitamin KVitamin K Vitamin EVitamin E

Thiamine Vitamin BVitamin B11 Biologically active formBiologically active form

thiamine pyrophosphate (TPP)thiamine pyrophosphate (TPP) Also can have TTPAlso can have TTP

FunctionFunction cofactor in oxidative decarboxylation of cofactor in oxidative decarboxylation of

-keto acids (TCA, AA degradation)-keto acids (TCA, AA degradation) RC(O)COOH to RC(O)OH + CORC(O)COOH to RC(O)OH + CO22 Other coenzymes also involved in Other coenzymes also involved in

processprocess Role of B1: H between S and N is very Role of B1: H between S and N is very

acidic; when removed makes an ylideacidic; when removed makes an ylide SourcesSources

pork, whole grains, legumes, tuna, soy pork, whole grains, legumes, tuna, soy milkmilk

RDARDA 0.5 mg/1000 Cal intake or min 1 mg/day0.5 mg/1000 Cal intake or min 1 mg/day req. increase with high carb diet or req. increase with high carb diet or

elevated metabolic needselevated metabolic needs DeficiencyDeficiency

decreased ATP productiondecreased ATP production impaired cellular functionimpaired cellular function Beri-BeriBeri-Beri Wernicke-Korsakoff Syndrome, aka Wernicke-Korsakoff Syndrome, aka

“cerebral Beri-Beri”“cerebral Beri-Beri”

HOH2N

N+

S

N

N

H2N

N+

S

N

N

PO

O

O

O

O

P

O

O

ATP

AMP

Riboflavin Vitamin BVitamin B22; vit G?; vit G? Biologically active formsBiologically active forms

Flavin mononucleotide (FMN)Flavin mononucleotide (FMN) Flavin adenine dinucleotide (FAD)Flavin adenine dinucleotide (FAD)

FunctionFunction Electron transferElectron transfer FMNHFMNH22, FADH, FADH22 Redox reactions (TCA, glycolysis, etc.)Redox reactions (TCA, glycolysis, etc.) Needed for good vision and healthy skinNeeded for good vision and healthy skin

SourcesSources Milk, mushrooms, tomatoes, liver, green Milk, mushrooms, tomatoes, liver, green

leafy vegetablesleafy vegetables RDARDA

1.1-1.3 mg/day1.1-1.3 mg/day DeficiencyDeficiency

Growth retardationGrowth retardation AriboflavinosisAriboflavinosis

CheilosisCheilosis Glossitis Glossitis StomatitisStomatitis

NNH

O

N

OH

OH

OH

OH

N O

Niacin Nicotinic acid, Vitamin BNicotinic acid, Vitamin B33 Biologically active formsBiologically active forms

NADNAD++, Nicotinamide adenine dinucleotide , Nicotinamide adenine dinucleotide NADPNADP++ Nicotinamide (readily deaminated, also in Nicotinamide (readily deaminated, also in

diet)diet) FunctionFunction

Coenzymes in redox reactions (TCA, FA Coenzymes in redox reactions (TCA, FA synthesis, gluconeogenesis, etc.)synthesis, gluconeogenesis, etc.)

DNA repairDNA repair SourcesSources

Unrefined grains, fortified cereal, meat, Unrefined grains, fortified cereal, meat, fish, tomatoes, mushrooms, milk, liver, ricefish, tomatoes, mushrooms, milk, liver, rice

Metabolism of tryptophan when AA is Metabolism of tryptophan when AA is abundant (needs riboflavin and B6)abundant (needs riboflavin and B6)

RDARDA 14-16 NE/day (NE = niacin equivalents = 1 14-16 NE/day (NE = niacin equivalents = 1

mg niacin or 60 mg tryptophan)mg niacin or 60 mg tryptophan) DeficiencyDeficiency

Pellagra = “rough skin” in ItalianPellagra = “rough skin” in Italian ToxicityToxicity

Skin inflammation, heartburn, nausea, liver Skin inflammation, heartburn, nausea, liver damagedamage

HN O

O

HN O

NH2

Pyridoxine Vitamin BVitamin B66, pyridoxal, pyridoxamine, pyridoxal, pyridoxamine Biologically active formBiologically active form

pyridoxal phosphate (PLP)pyridoxal phosphate (PLP) FunctionFunction

Coenzyme for transamination reactions, Coenzyme for transamination reactions, esp. AAs (neurotransmitters)esp. AAs (neurotransmitters)

Decarboxylation of carboxylic acidsDecarboxylation of carboxylic acids SourcesSources

Wheat, corn, egg yolk, liver, potato, Wheat, corn, egg yolk, liver, potato, banana, fish, chickpeasbanana, fish, chickpeas

RDARDA 1.3-1.7 mg1.3-1.7 mg

DeficiencyDeficiency Induced by TB drug isoniazid (supplement Induced by TB drug isoniazid (supplement

given)given) Dermatitis, fatigueDermatitis, fatigue Depression, confusionDepression, confusion Convulsions, seizuresConvulsions, seizures Microcytic hypochromic anemiaMicrocytic hypochromic anemia Epidemic in 1950sEpidemic in 1950s

ToxicityToxicity Neurological disorders at > 2 g /dayNeurological disorders at > 2 g /day

Biotin B7B7 Biologically active formBiologically active form

Binds to lysine residue of enzymeBinds to lysine residue of enzyme FunctionFunction

Cofactor in carboxylation reactions, Cofactor in carboxylation reactions, carrier of COcarrier of CO2 2 (acetyl-CoA to malonyl-(acetyl-CoA to malonyl-CoA, synthesis of fatty acids)CoA, synthesis of fatty acids)

Regulation of gene expressionRegulation of gene expression SourcesSources

Almost all food, esp. milk, egg yolk, Almost all food, esp. milk, egg yolk, tomato, almond, peanuts, avocado, tomato, almond, peanuts, avocado, mushroommushroom

Also synthesized by intestinal bacteriaAlso synthesized by intestinal bacteria RDARDA

At least 30 At least 30 g/dayg/day DeficiencyDeficiency

Deficiency does not occur naturally Deficiency does not occur naturally unless eat 20 raw egg whites per day unless eat 20 raw egg whites per day (protein avidin binds biotin (protein avidin binds biotin irreversibly and excreted)irreversibly and excreted)

Why raw? Why raw?

OH

NHO H

HN

HS

O

Folic acid Biologically active formBiologically active form

Tetrahydrofolate (THF)Tetrahydrofolate (THF) FunctionFunction

Stimulates digestive acids; appetiteStimulates digestive acids; appetite Receive one carbon fragments from Receive one carbon fragments from

donors and transfer them in AA synthesis donors and transfer them in AA synthesis and nucleotide synthesisand nucleotide synthesis

SourcesSources Green leafy veggies (“foliage”), organ Green leafy veggies (“foliage”), organ

meats, legumes, okra, whole grain meats, legumes, okra, whole grain cerealscereals

RDARDA 400 400 g/day, more during pregnancy and g/day, more during pregnancy and

lactationlactation DeficiencyDeficiency

Megaloblastic/macrocytic anemia and Megaloblastic/macrocytic anemia and growth failuregrowth failure

Once, most common vitamin deficiency Once, most common vitamin deficiency in US; now fortified cerealsin US; now fortified cereals

Absorption inhibited by many medicines, Absorption inhibited by many medicines, so a problem with the elderlyso a problem with the elderly

Cobalamin Vitamin BVitamin B1212

Corrin ring system with Co in centerCorrin ring system with Co in center FunctionFunction

Synthesis of MetSynthesis of Met Methylmalonyl-CoA to succinyl-CoAMethylmalonyl-CoA to succinyl-CoA

Degradation of odd-chain FA, enter Degradation of odd-chain FA, enter TCATCA

Transfer of methyl groupsTransfer of methyl groups Produce red blood cellsProduce red blood cells

SourcesSources Liver, whole milk, cottage cheese, Liver, whole milk, cottage cheese,

oysters, salmon, clams, eggs, oysters, salmon, clams, eggs, shrimp, pork, chicken (animal shrimp, pork, chicken (animal sources)sources)

RDARDA 2.4 2.4 g/dayg/day

DeficiencyDeficiency Caused by pernicious anemiaCaused by pernicious anemia Methylmalonic acidemia (MMA) Methylmalonic acidemia (MMA)

Ascorbic Acid Vitamin CVitamin C FunctionFunction

Reducing agent, readily oxidized by OReducing agent, readily oxidized by O22 React with free radicals that can damage React with free radicals that can damage

DNA, proteins, lipids, etc.DNA, proteins, lipids, etc. Reduces Fe(III) to Fe(II) for absorptionReduces Fe(III) to Fe(II) for absorption Hydroxylation processes (synthesis of Hydroxylation processes (synthesis of

collagen)collagen) SourcesSources

Citrus, potato skins, tomatoes, green veggies, Citrus, potato skins, tomatoes, green veggies, blueberries, peppers, papaya, strawberriesblueberries, peppers, papaya, strawberries

RDARDA 10 mg/day to prevent scurvy10 mg/day to prevent scurvy 75-90 mg/day recommended; more if you 75-90 mg/day recommended; more if you

smoke b/c of free radicals in smokesmoke b/c of free radicals in smoke DeficiencyDeficiency

Scurvy = swollen and bleeding gums, loose Scurvy = swollen and bleeding gums, loose teeth, red spots on skin from internal bleedingteeth, red spots on skin from internal bleeding

Weakened connective tissue, slow-healing Weakened connective tissue, slow-healing wounds, anemiawounds, anemia

ToxicToxic Metabolize to oxalateMetabolize to oxalate GI problems, so cap dosage at 2 g/dayGI problems, so cap dosage at 2 g/day

OH

OH

HO

OO

HO

Pantothenic acid Vitamin BVitamin B55 FunctionFunction

Component of CoA (transfer of Component of CoA (transfer of acyl groups, most commonly acyl groups, most commonly acetyl)acetyl)

Component of fatty acid Component of fatty acid synthase complexsynthase complex

SourcesSources Eggs, liver, yeast, yogurt, Eggs, liver, yeast, yogurt,

salmon, turkey, sunflower salmon, turkey, sunflower seeds, mushroomsseeds, mushrooms

RDARDA 4-5 mg/day4-5 mg/day

DeficiencyDeficiency Rare due to abundance in foodsRare due to abundance in foods Not well characterizedNot well characterized Burning feet syndromeBurning feet syndrome

HNHO

HO O

O

OH

Vitamin A Collective term for retinol, retinal, retinoic acidCollective term for retinol, retinal, retinoic acid Formed from oxidative cleavage of Formed from oxidative cleavage of -carotene (in liver)-carotene (in liver) FunctionFunction

Aldehyde: visual cycle/processAldehyde: visual cycle/process Alcohol, carboxylic acid: growth, reproductionAlcohol, carboxylic acid: growth, reproduction

SourcesSources Liver, kidney, cream, butter, egg yolk (animal sources)Liver, kidney, cream, butter, egg yolk (animal sources) Yellow and green veggies: carotene precursors (pumpkin, sweet Yellow and green veggies: carotene precursors (pumpkin, sweet

potato, carrots)potato, carrots) RDARDA

700-900 RE 700-900 RE RE = retinol equivalent RE = retinol equivalent

= 1 micro-g retinol or = 1 micro-g retinol or 12 micro-g 12 micro-g -carotene-carotene

DeficiencyDeficiency HyperkeratosisHyperkeratosis Night blindnessNight blindness XerophthalmiaXerophthalmia

ToxicityToxicity Levels over 7500 RELevels over 7500 RE

H3C CH3

CH3

CH3 CH3

CH3 CH3H3C CH3

H3C

CH3 CH3

CH2OHH3C CH3

CH3

Beta-carotene

Retinol (vitamin A)

Vitamin D Group of compounds, steroids with Group of compounds, steroids with

open B ringsopen B rings Most prevalent = DMost prevalent = D33 DD33 active form = 1,25- active form = 1,25-

dihydroxycholecalciferoldihydroxycholecalciferol FunctionFunction

Regulate Ca and P absorption during Regulate Ca and P absorption during bone growthbone growth

SourcesSources Diet: DDiet: D22 (milk additive, plant sources) (milk additive, plant sources)

and Dand D33 (animal sources) (animal sources) Precursor: intermediate in cholesterol Precursor: intermediate in cholesterol

synthesissynthesis Formed in skin non-enzymatically from Formed in skin non-enzymatically from

steroid 7-dehydrocholesterolsteroid 7-dehydrocholesterol RDARDA

5 5 g Dg D33 DeficiencyDeficiency

Soft bones, impaired growth and Soft bones, impaired growth and skeletal deformities in children skeletal deformities in children (Rickets)(Rickets)

Also caused by antiepileptic drugsAlso caused by antiepileptic drugs ToxicityToxicity

Most toxic (stored, slowly metabolized)Most toxic (stored, slowly metabolized)

Vitamin K Phylloquinone or menaquinonePhylloquinone or menaquinone FunctionFunction

Synthesis of blood-clotting Synthesis of blood-clotting proteinsproteins

SourcesSources KK11 = plants; K = plants; K22 = animals, bacteria = animals, bacteria

in intestinein intestine Cabbage, cauliflower, spinach, egg Cabbage, cauliflower, spinach, egg

yolk, liveryolk, liver RDARDA

90-120 90-120 g/dayg/day DeficiencyDeficiency

Unlikely due to synthesis and wide Unlikely due to synthesis and wide distribution in fooddistribution in food

Injection for infantsInjection for infants ToxicityToxicity

JaundiceJaundice

CH3

CH3

O

O CH3 CH3

Vitamin K1 (phylloquinone)

CH3

CH3

O

O CH3 CH3

Vitamin K2 (menaquinone)

Vitamin E -Tocopherol-Tocopherol FunctionFunction

Antioxidant, prevent oxidation of Antioxidant, prevent oxidation of polyunsaturated FAs in polyunsaturated FAs in membranes by Omembranes by O22 and free and free radicalsradicals

SourcesSources Vegetable oils, liver, eggs, nuts, Vegetable oils, liver, eggs, nuts,

seeds, spinach, tomatoesseeds, spinach, tomatoes RDARDA

15 mg15 mg DeficiencyDeficiency

Associated with defective lipid Associated with defective lipid transport/absorptiontransport/absorption

Hemolytic anemiaHemolytic anemia ToxicityToxicity

Least toxic of fat-soluble vitaminsLeast toxic of fat-soluble vitamins

O

CH3

HO

H3C

CH3

CH3

CH3

CH3 CH3 CH3

Olestra Artificial, noncaloric fat substitute (indigestible)Artificial, noncaloric fat substitute (indigestible) FDA warningFDA warning

““This Product Contains Olestra. Olestra may cause abdominal This Product Contains Olestra. Olestra may cause abdominal cramping and loose stools. Olestra inhibits the absorption of cramping and loose stools. Olestra inhibits the absorption of some vitamins and other nutrients. Vitamins A, D, E, and K some vitamins and other nutrients. Vitamins A, D, E, and K have been added.” have been added.”

OH

O

H

H

OH

O

CH2

H

CH2

HCH2

O H

H O

O

O

OC

O

R

OC

R

O

C

R

O

C

R

O

OC

R

O

C

R

O

CR

O

O

R

R = (CH2)7CH=CH(CH2)7CH3