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27 Cards in this Set
- Front
- Back
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Protein
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C, H, N, O
have amino acids side chains are what makes the AA's different 4cal/gm 21 AA's-essential |
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Function of protein-body
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structural(muscle and hair)
enzymes-control chemical reactions carrier proteins (hemoglobin, myoglobin) messenger proteins |
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Biological Value
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measure of protein quality
-proportion of absorbed protein after ingestion -how readily the broken down protein can be used in protein synthesis |
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Properties of a Protein Source affect its BV
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1. AA compostion and any limiting AA
2. Preparation 3. vitamin and mineral content(can serve as co-enzymes) |
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Functions in Food
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color-maillard reaction
flavor-maillard reaction texture-denaturation; water binding properties |
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Peptide Bond
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link from N of one AA to C of the other AA
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Protein tertiary structure
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3-D shape, folded protein, hydrogen and disulfide bonds
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2 Types of tertiary structure
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globular
fibrous(elastin and collagen) |
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Globular
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albumins, readily coagulated by heat, soluble in water, denature quicker than fibrous
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Fibrous
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water soluble
Elastin: high in high use muscles (heat makes it shrink and harden-toughness) gives elasticity Collagen: insoluble protein in CT, white in color |
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Collagen
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shrink lengthwise with heat; water binding capacity is reduced because fibers narrow; long slow cooking= some of collage gelatinizes
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Physical Characteristics of meat
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muscle tissue(actin and myosin)
CT (elastin and collagen) Fatty tissue |
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Fat in protein
(3) |
subcutaneous fat
intermuscular fat intramuscular ft |
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CT in animals
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older animals more CT
less CT more tender and vice cersa elastin can not be softened by cooking |
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Lean/High Fat meat
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muscle tissue, red, little marbling
increased marbling (% of fat increases as animal's age increases) |
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Chemical composition of meat
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water 45-70%
protein 15-20% fat 5-40% |
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Hemoglobin
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carries oxygen in the bloodstream; iron containing
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Myglobin
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stores oxygen in the muscle ; contributes to purplish red color of meat; present in well-exercised portions (dark meat)
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Metmyoglobin
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produced over time; due to oxidation of iron molecule (bad ? )
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Denaturation
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by heat(pasteurization, cooking)
pH change salt concentration freezing surface changes(beaten white eggs) desired or undesired |
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coagulation
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precipitation of protein as molecules combine
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Dried Beans and Peas as protein
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incomplete proteins; need 2 or more plant proteins to obtain all 9 essential amino acids
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Eggs
function |
complete protein
binding emulsification (mayo) foaming gelling thickening |
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Processing and preservation of eggs
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freezing, denaturing, dehydration,
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Milk
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88% water
pasteurized to destroy pathogens homogenized (emulsify fat and prevent creaming) casein (milk protein, precipitated as a curd) whey proteins (not precipitated by acid) curd (coagulated casein plus fat) |
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Fish
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good source of all essential AA's, unsaturated fatty acids
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TMAO
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substance on fish no odor
TMAO + bacteria and microorganisms = TMA (fishy smell ) |
