Final Study Guide
Final Study Guide NHM 253
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This 19 page Study Guide was uploaded by Ally Siegler on Monday February 9, 2015. The Study Guide belongs to NHM 253 at University of Alabama - Tuscaloosa taught by Dr. Crowe in Fall. Since its upload, it has received 368 views. For similar materials see Food Science in Nutrition and Food Sciences at University of Alabama - Tuscaloosa.
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Date Created: 02/09/15
NHM 253 Final Exam Study Guide The exam is comprehensive With 20 questions selected from the guide below Remember this is only a GUIDE to how to best for the comprehensive portion of the exam The remainder of the questions approximately 30 will be taken from the last three lectures covering meat fish and poultry 0 Functions of all three macronutrients in food 0 Carbohydrates 0 Contribute sweetness avor 0 Color 0 Moisture absorption 0 Texture amp thickening 0 Preservation 0 Fermentation 0 Heat transfer 0 Tenderization 0 Emulsification 0 Texturemouthfeel 0 Flavor satiety 0 Proteins 0 Hydration 0 Denaturationcoagulation 0 Enzymatic reactions 0 Browning 0 Buffering 0 Heat transfer during moist and dry methods of cooking Conduction direct transfer of heat from one substance to another that it is contacting 0 Ex grilling frying Convection transfer of heat by moving air or liquid currents through andor around food 0 Ex convection oven steaming simmering deepfrying Radiation transfer of heat energy in form of waves of particles moving outward from their source 0 Ex microwave ovens infrared heat lamps oven Induction transfer of heat energy to neighboring material without contact 0 Ex atsurfaced ranges 0 Factors affecting microbial growth Biological bacteria viruses mold and their toxins and parasites 0 Usually transmitted by preparer 0 Most common cause of illness Chemical sanitizers cleaning agents pesticides antibiotics hormones toxic metals etc Physical glass wood plastic metal shavings from can opener hair etc Protein and water content FATTOM food acidity time temp oxygen moisture 0 Most bacteria inhibited below 46 0 Proteins denature at llOF 0 Basic differences between commonly used food preservation methods 0 Drying decreasing water content 0 Refrigeration slowing enzyme reaction rates and rate of microbial growth with low temperature 0 Freezing binds moisture so it is unavailable to microorganisms chemical and physical reactions are slowed 0 Fermentation lowers pH of product salt added to pull moisture out of product 0 Pickling 0 Canning food is sealed in cans or jars and heated to high temperatures destroying microorganisms and enzymes 0 Irradiation destroys chemical bonds within enzyme systems and DNA in microorganisms 0 Considered a food additive by FDA 0 Aka cold sterilization 0 Edible coatings barrier to 02 gases and moisture loss 0 Curing high concentrations of salt added to bind water 0 Pasteurization high heating liquids to kill MOs 0 Vegetables and Fruit 0 Plant pigments including in uence of heat pH oxygen on stability 0 Carotenoids carotenes lycopene lutein xanthophyll zeaxanthin 0 Fatsoluble 0 Stable in heat except prolonged exposure 0 Oxygen causes pigment oxidation 0 pH stable in acid and alkali 0 most stable pigment 0 Chlorophyll A amp B 0 Fatsoluble 0 Stable in minimal heat 0 Changes to Pheophytin duller green 0 pH stable in alkali unstable in acid 0 Oxygen 0 Flavonoids anthocyanins anthoxanthins betalains 0 Watersoluble 0 Minimal heat 0 Oxygen causes pigment oxidation and loss of antioxidant properties 0 pH stable in acid unstable in alkali 0 Enzymatic browning including methods for prevention 0 Phenolic compounds enzymes oxygen browning 0 Phenolic compounds and enzymes are separated by cell walls 0 Once fruit is droppedcut cell structure is interrupted causing them to come in contact with each other and oxygen 0 Temperature enzyme actiVity is slowed by cold temps heat denatures 0 pH enzyme actiVity is inhibited in low pH 0 addition on lemon juice sprite vinegar etc 0 Coating with sugar blocks oxygen from contact 0 Sulfur compounds food antioxidants react with 02 and prevent reactions with phenolics and enzymes 0 Grains and Starch Functionality 0 Composition of our 0 Husk protective outer coating often removed 0 Bran protective coating of endosperm high in fiber vit B and minerals 0 Endosperm starch house of the grain basis of all ours 0 Germ embryo of plant high in fat vit E and B 0 Composition of starch amylose and amylopectin differences 0 Amylose long chains of glucose that absorb water easily 0 Thicken and swell when heated with water 0 Amylopectin shorter branched chains of glucose that do not hydrate well 0 Waxy texture 0 Functionality in Food Systems gelatinization gel formation etc 0 Dextrinization breakdown of starch under extreme heat resulting in shorter sweeter strands and forming dextrose 0 Gelatinization cooking of starch granules causing water absorption resulting in the swelling and softening of granules 0 Temp stirring acidity sugar 0 Gel Formation upon cooling gelatinized starches convert into a gel primarily amylose by binding water 0 Retrogradationsynerisis seepage of water out of an aging gel because of the tightening of amylose bonds 0 Baking 0 Gluten and gelatinization impact on texture 0 Gluten gliadin glutenin 0 Gives rise to breads enabling dough to retain trapped gasses provides structure responsible for volume and textural characteristics 0 Higher amounts of protein tougher bread 0 Flour starch protein 0 Leavening types and differences between 0 Physical air and steam 0 Incorporated by mixingbeating 0 Contributes 50 of volume between air 10 and steam 40 0 Chemical baking powder and baking soda 0 Release C02 through reactions between acids and bases in presence of a liquid 0 Soda alkaline ONLY needs acid to react 0 Powder complete and ready for reaction double acting 0 Biological yeast and bacteria 0 Consume sugar and respire C02 0 Impact of six primary categories of bakeshop ingredients on final texture of baked products 0 Flour provides structure via starch and protein content 0 Leavening cause dough or batter to rise 0 Sugar increase volume of baked goods temp for gelatinization food for yeast moistness and tenderness browning 0 Fat avormouthfeel increased volume strength richness and moisture tenderization shortening gluten strands delayed staling extends shelflife 0 Liquid avor enhancer via fat and sugar tenderization of gluten via fat and sugar protein adds structure dispersing agent 0 Salt avor development strengthening of gluten network ionizes sulfur bonds modifies yeast activity preservative Meat fish and poultry Types of meat 0 O 0 Beef cattle classified according to age and gender I Steer male cattle castrated early and will gain weight quickly I Bulls older uncastrated males usually used for processed meat and pet foods stag meat I Heifers females that have not borne a calf 0 Meat from cows that have borne a calf is less desirable I Calves 38 months old referred to as baby beef Veal young calves between 3 weeks and 3 months I Fed milkbased diet and have movement restricted Lamb lt 14 months mutton gt 14 months Pork pig lt 4 months hog gt 4 months age impacts texture younger more tender Composition of meat 0 Water muscle connective tissue adipose 0 Marbling fat embedded Within the muscles major determinant of quality and price of meat I Improves mouthfeel avor and tenderness I Age diet heredity have in uence on fat texture 0 Muscle actin thin and myosin thick filaments contract to make actinomyosin at their zlines that separate sarcomeres I Size of fibers vary by age I Older larger fibers and less tender I Crosslink to combine two and contract 0 Connective tissue protein matrix that holds cells together mucopolysaccarides I Type and amount determines tenderness and cooking method I Collagen tough fibrous matrix that converts to gelatin With heat 0 Higher in muscles for locomotion and in older animals I Wraps muscle fibers I Elastin rubbery elastic matrix that doesn t soften during cooking 0 Found primarily in tendons and ligaments 0 Does NOT denature 0 Mostly removed before cooking 0 Color chemistry 0 Myoglobin purplered I Ironcontaining protein that binds 02 in muscle I Gives coloration to meat I Heme ironcontaining portion of myoglobin O Oxymyoglobin bright red desired color of retail meat I Results from exposure of myoglobin to 02 I Oxygenation initial contact of myoglobin and 02 O Metmyoglobin brownred I Prolonged exposure to oxygen or bacterial in uence causes uncooked meat to brown I Less nutritious I Oxidation long storage time 02 strips oxymyoglobin away 0 Extractives 0 Flavor compounds consisting of nonprotein nitrogen substances that are endproducts of protein metabolism 0 Give avor to meat 0 Older the meat the more extractives and more avor I Determinants of tenderness O CUT OF MEAT number 1 some muscles are moved more than others and Will therefore be less tender When cut I Flank short plate brisket least tender shoulder and legs I Sirloin tenderloin ribeye most tender neck and back 0 Age younger is more tender 0 Heredity and breed characteristics marbling muscle size 0 Diet grass v grain fed I Grain fed more tender but unnatural 0 Marbling more more tender 0 Type of agingelectrical stimulation of meat hastens tenderization 0 In uence of preparation enzymes may be applied 0 Aging meats 0 Rigor mortis Postmortem physical and biochemical event resulting in crosslinking of actin and myosin causing muscle tissues to stiffen and contract WITHOUT 02 I If not let go through called green meat I 624 hours upon death I Reverses 12 days after slaughter I Uses glycogen instead of 02 converts to lactic acid lowers pH 0 Aging Natural enzymes within meat begin to break down and tenderize 3D protein molecules 0 Release ions that ionize proteins 0 Lowers pH from 7 to 58 which is ideal for waterholding capacity and meat quality 0 Improves tenderness moisture content avor color and ability to brown during cooking 0 Not all meats are aged primarily affects beef due to older age and increased life activity I Older animals are aged because not as tender as young I Cows have larger muscle fibers that need to be broken down I Antibiotics and hormones O 20 million pounds of antibiotics given to livestock each year I Drugs are to be withheld before slaughter so residues fall below federal limits I Could contribute to growth and spread of drugresistant bacteria O Hormones rapid weight gain reach weight sooner reduce production cost I Human health consequences Environmental I 34ths of cattle are treated 0 Artificial tenderization 0 Enzymes proteolytic relax and breakdown muscle proteins I Injected into bloodstream 10 min before slaughter I Not activated until exposed to heat in preparation I Shortens time of rigor mortis and aging I Commercial meat tenderizers used at home effective on thin cuts of meat I EX ficin fig papain papaya bromelain pineapple O Salts aid in moisture retention and ions of Na K and Mg help break down protein components I Do not tenderize but allow meat to retain moisture and cause us to salivate indirect tenderizer O Acids assist in breaking down proteins allowing avors to penetrate Ionize and denature I Increase color and avor Break down outside surface more tender and avor I EX lemon juice sprite vinegar 0 Mechanical tenderization grinding cubing needling and pounding meat to break down proteins and soften meat 0 Electrical stimulation hastens rigor mortis I Does not work on piggys I After slaughter before rigor mortis I Kosher meat is not stimulated 0 Inspection MANDATORY O O 0 By USDA determines wholesomeness Food Safety Inspection Services Antemortem live inspection for signs of disease Postmortem dead inspection includes muscle inspection for disease 0 Grading VOLUNTARY O O O O USDA or private systems paid for by manufacturer Take into consideration age meat color meat texture degree of marbling Prime tender juicy avorful greatest degree of marbling most expensive Sold to fine restaurants and meat stores Choice found in retail stores Select less marbling lower in price Must be cooked lower and slower in moist heat Kobe beef higher price omega3amp6 are fed beer to deposit fat No roll is ungraded meat 0 Storage and Preparation 0 O PHF due to high water and protein content Should be stored at low temperatures for short amounts of time I 34 days refrigerated I Ground meat 12 days because it has been exposed to more 02 than others during grinding Frozen meats can be stored for up to 6 months Larding inserting strips of fat into slits in the meat with a large needle O Barding tying thin sheets of fat over lean meat to keep moist during roasting removed before serving Searing cooking to a high internal temp to seal pores increases avor and color Blanching boiling meat brie y to lock in juices no longer used 0 Doneness O 0 Color and touch I Rare strong red interior spongy 39 Medium pink interior springy to slightly firm I Well brown interior firm texture moist but not juicy Accuracy requires use of thermometer inserted at the thickest portion of the muscle away from bone 0 Sale weight DOES NOT cooked weight 0 Water and collagen are lost with heat 0 Types of Poultry 0 O O 0 Chicken duck turkey geese guinea pigeons Broilersfryers under 10 weeks 35 pounds Roasters older and larger 68 pounds Capons neutered male chickens under 4 months 1214 pounds Cornish game hens crossbred 56 weeks less than 2 pounds Mature over 10 months best used in stews soups 0 Muscle Composition 0 Muscle cells and fibers along with connective tissue O O I Less connective tissue than meats Does not contain intramuscular fat fat stored in abdominal cavity and in tail White V dark meat is identified by amount of myoglobin in muscle I Increased amounts of myoglobin is found in muscles used more frequently such as thighs and drumsticks I Wild birds are darker because utilize more movement throughout lifetime 0 Tenderness O 0 Location and activity of muscle Age Heredity and Breed characteristics Diet In uence of preparation 0 Inspection MANDATORY O O USDAFSIS for safety Antemortem and postmortem for signs of disease 0 Grading VOLUNTARY 0 Quality oriented 0 Grades AC I A retail sale I B and C are generally processed into poultrybased products 0 Storage 0 PHF due to high protein content O Foodborne illness concerns salmonella and campylobacter 0 Low temp for short time I 34 days refrigerated I ground poultry 12 days 0 Frozen 6 months 0 ThaWing I Under cold running water I Refrigerated safest and most economical 0 Determining Doneness O Accurate thermometer I 165 F is minimum internal temp O Juices turn pink to clear 0 Timeweight charts are useful 0 Popup indicators are not always reliable 0 Fish and Shellfish O Finfish I Fresh and Salt water I Lean and fatty O Shellfish I Crustacean I Crab lobster shrimp I Mollusk 0 Bivalve O Clam mussel scallop I Univalve O Conch snail I Cephalopod O Squid octopus 0 Composition 0 More tender than other meats because of I Lower collagen amounts 3 V 15 I Higher amino acid content in collagen results in breakdown at lower temps I Shorter fiber bundles than land animals 0 lt5 glycogen breaks down into CHO giVing slight sweet avor 0 High protein content 0 Muscle structure I Myotomes shorter fibers I Myocommata connective tissue that separates myotomes 0 Rich source of highly unsaturated fatty acids Omega3 s I Decrease in risk of heart disease I Alleviates psoriasis and in ammatory diseases 0 Rheumatoid arthritis 0 Lupus 0 Pigmentation 0 Concentration of myoglobin depends on characteristic movements of fish I Red or darker slow twitch fibers used for long endurance swimming 0 EX salmon I Whitepale fast twitch fibers for short bursts of energy I Tuna concentrations of both variety of colors 0 Higher fat content darker esh I Seen in cold water fish for insulationneed more oxygen 0 Astaxanthin redorange pigment with strong antioxidant capacity found in bottomfeeders and shellfish I Sold as supplement 0 Inspection VOLUNTARY 0 By US Department of Commerce and National Marine Fisheries Service 0 Wholesomeness and sanitary conditions of processor 0 Shellfish Certification MANDATORY I Harvesting from certain water I ICSSL I Containers must be labeled with harvester s name address and certification number date of harvest location type and quantity of shellfish I Must keep sellby tags for 90 days 0 Water is assessed not fish themselves all about water quality 0 Perishability of Fresh Fish O Microbiology I Fish esh is sterile internally I Bacteria on surface or in intestines rapidly invade all tissues upon death I Psychotropic affect neurological function 0 Flourish in refrigerated conditions 0 Physiology I Struggle during capture renders all glycogen spent I If present would ve converted to lactic acid and preserved fish by lowering pH 0 Acidity inhibits bacteria growth I Bacteria are uninhibited and spoilage rapidly ensues 0 Fat Chemistry I Lipids are easily oxidized because unsaturated I Trimethylamine Oxide phospholipid associated with fish fat that is oxidized to produce odorous compound TMA of decaying fish I Hastened by enzymes within fish and indigenous bacteria 0 TMA fishy smell 0 Fresh fish should not smell this way 0 Signs of Decay 0 Eyes atten become concave 0 Red gills turn brown or dull myoglobin gt metmyoglobin O Filet should be at shiny firm and free of gaping 0 Storage O O Foodborne illness from psychotropic bacteria ourish under refrigeration Uncooked fish should be cooked Within 48 hours Frozen up to 9 months 0 Doneness aking 0 Lean V fatty fish 0 Fatty fish are found in cold water 0 Mercury content 0 O In water from natural or industrial sources Taken up into gills of fish as they swim and stays for long periods of time in esh Large fish consume small fish therefore increasing mercury content
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