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56 Cards in this Set
- Front
- Back
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What are the classifications for meats, poultry, fish? |
Meat: red meats from animal sources; beef, veal, pork, lamb Poultry: meats from fowl; turkey, chicken, ducks, pheasants Fish: meat from aquatic animals; meat from fish with fins, gills, backbone, and skull and also shellfish: meat from mollusks and crustaceans crustaceans: shrimp, lobster, crabs |
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What is the structure of meat? |
Muscle tissue, connective tissue, fat |
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How many grams of protein per ounce of meat? |
7g |
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What are the different types of protein? |
Contractile proteins: actin and myosin Hemoglobin: carries oxygen in blood Myoglobin: carries oxygen in muscle Enzymes Connective tissue proteins: elastin and collagen |
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What is the composition of muscle tissue? |
- Lipid: amount varies from 4-10% - Proteins: contractile proteins & enzymes - Carbohydrate: glycogen - Vitamins: highly bioavailable in iron, source of zinc, B vitamins, in pork high in thiamin |
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What is responsible for the drop in pH after slaughter and onset of rigor mortis? |
ATP-ase The drop in pH is due to lactic acid |
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What is responsible for the moistness or water holding capacity (WHC) of meat? |
Pyrophosphatase |
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What are the poteolytic enzymes active in meat post-rigor and also tenderizes meat after rigor mortis? |
Cathepsins |
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What is the muscle organization? |
Muscle --> bundles of fibers --> fibers --> myofibrils --> sarcomeres --> organized actin and myosin myofilaments |
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How do muscles contract and what do they create when they contract? |
Myosin (thick) and Actin (thin) contracting creating actinomyosin |
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What does contraction/relaxation require? |
Contraction requires calcium Relaxation requires ATP |
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What determines the tenderness of the meat? |
Connective tissue |
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What is the structural roles of connective tissue? |
- forms walls of muscle fibers and binds into bundles - makes up tendons and ligaments - concentrated in moving parts of animals |
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What are the 4 categories of materials that are abundant in the connective tissue of meats and which is the most? |
1. Collagen: 25-35% 2. Elastin 3. Reticulin 4. Ground substance |
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Where is collagen found? |
structural sheaths within and between muscle fibers |
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What is a fibrous protein composed of 3 strands of collagen known as? |
tropocollagen |
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What is the color of collagen? |
white |
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What are the changes that occur during cooking when cooking collagen? |
collagen is converted into gelatin (tender) |
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What does elastin look like and color? |
Elastic, rubbery, yellow |
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Where is elastin found? |
Blood vessels and ligaments; found in limited amounts intramuscularly |
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What are the changes that occur when cooking elastin? |
Doesn't soften with cooking (creates toughness) gristle |
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What is reticulin? |
A fibrous protein linked with fatty acids that forms mesh-like network |
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What is ground substance? |
matrix of plasma proteins and glycoproteins in which collagen and/or elastin are bound |
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Are connective tissues intracellular or extracellular? |
Extracellular |
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What is endomysium? |
connective tissue between fibers |
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What is perimysium? |
Connective tissue surrounding a bundle of several fibers |
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What is epimysium? |
connective tissue surrounding an entire muscle (many bundles of bundles of fibers) |
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What lipid occurs in the muscle tissue and fatty deposits or fat depots and what does it contribute to? |
Triglycerides - contributes to flavor and juiciness |
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What are the main fatty acids, subcutaneous fats, and other fats in meat? |
main fatty acids: oleic, palmitic, stearic subcutaneous fats: more unsaturated fats other lipids: phospholipids, cholesterol |
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What are the two main pigments in meat? |
Hemoglobin Myoglobin (most prominent) |
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What do hemoglobin and myoglobin have in common? |
both iron-containing pigments with heme |
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Muscle has 3x as much what |
3x as much myoglobin than hemoglobin |
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What are the 3 parts myoglobin is made up of? |
Iron, Globin (globular protein), Heme (pigment) |
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What does the intensity of myoglobin color vary with? (6) |
- species (pork is less than beef) - age (less in younger) - exercise (more with exercise) - exposure to O2 - exposure to heat - storage/processing |
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What can the iron in heme cause pigment color changes by? |
- complexing with other atoms or compounds - changing valence |
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What can myoglobin change into? |
Can form oxymyoglobin or metmyoglobin |
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What color does oxymyoglobin and metmyoglobin change into? |
Oxymyoglobin: bright red Metmyoglobin: brown |
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What is the light color in poultry due to? |
Hemoglobin |
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Why is salmon a reddish-orange color? |
Due to astaxanthin (carotenoid) |
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What is the color in fish due to? |
Combination of hemoglobin and myoglobin, depending on species and type of muscle |
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What happens when you heat meat, poultry, and fish? |
Meat: myoglobin --> oxymyoglobin --> denatured globin hemichrome (grayish-brown) Poultry: colorless Fin fish: increased opacity |
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What is the pink color during curing due to? |
Formation of nitric oxide myochrome and/or nitrosyl-hemochrome |
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What is the meat quality affected by? (5) |
- age of animal - slaughtering conditions - postmortem changes - storage conditions of carcass - many other factors that impact tenderness |
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When do the postmortem changes happen in meat? |
- occur during the aging process (chilled) - after 6-24 hours, rigor mortis occurs temporary rigidity |
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What happens when rigor mortis occurs? |
Decrease in pH, muscle fibers pack more closely together and push out water, actinomyosin formation, then disappears as enzymes break down proteins (48 hours) |
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Wat is a normal change in pH due to rigor mortis? |
7.0 to 5.6 |
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What is the drop in pH due to? |
Anaerobic metabolism of glycogen to lactic acid |
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What happens in stressed animals for rigor mortis? |
- have reduced glycogen - results in reduced lactic acid and a higher pH of 6.6 - called dark-cutting beef in beef too high |
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What happens to the pH in pork? |
5.1 --> 5.4 too low |
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What happens if you chill the meat too rapidly after slaughtering? |
can cause cold shortening (severe contraction of muscle) results in tough meat |
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What are the factors that affect the tenderness in meats? (1-4) |
- Cut (rib, short loin: tender) - Actinomyosin (contraction toughens; stretching softens) - Connective tissue (older animals have less soluble collagen) - Aging process (optimal time for beef is 11 days, pork is 3-5 due to rancidity and off flavors) |
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What are the factors that affect the tenderness in meats? (4-8) |
- Acids (have minimal effect on tenderness but increases water by altering protein solubility) - Salts (works to some extent, increases water retention) - Enzymes ( papain:papaya, bromelain:pineapple, ficin:figs - activated during cooking) - Mechanical manipulation (needles, blades, pounding, cubing, grinding) |
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Which is the most effective way to tenderize meats? |
Mechanical |
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What can toughen the meat? |
Excess heat (above 60C or 140F) |
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What are the effects of heat? |
Fat melts + proteins are denatured + water is lost |
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What happens when heating meat concerning water? |
As the proteins denature, they lose the tertiary structure and then the fibers shrink, reducing the water holding capacity - bound water = free water - meat loses the juiciness |
