Domain 1- Principles of Dietetics Flashcards
What causes the crispiness of vegetables?
Turgor- osmotic pressure in vacuoles
Soy protein
Mostly complete- Methionine is limiting am. ac.
Concentrates (70% protein)
Isolates (90%)
Enzymatic changes in fruits/veg
starch –> sugar
protopectin –> pectin –> pectic acid
Ethylene gas
accelerates ripening of fruits during storage
Preventing browning of cut fruits (3)
Citric acid, sugar, heat to boiling
Syrup density
Expressed at % by weight of sucrose
Measured in degrees Brix by Brix hydrometer
Labeled as extra light, light, heavy, extra heavy
Green pigments
Chlorophyll
+ acid = pheophytin (olive green)
+ alkaline = chlorophyllin (bright green, mushy)
Yellow pigments
Carotenoids
Little effect in acid/alkaline
Lycopene- red, antioxidant
Red/purple/blue pigments
Anthocyanins (Flavinoids)
+ acid = bright red
+ alkaline = bluish
White pigments
Anthoxanthins (Flavinoids)
+ acid = colorless
+ alkali = yellow (ex: onions cooked in aluminum pan)
Glutamic acid
Found in young vegetables
Used to make MSG
Tannins
Cause astringent feeling in mouth (ex: unripe bananas)
How to cook acidic vegetables
Longer time, use more water, no lid to let acid escape
How to cook cabbage
Short time, lid off initially, large amount of water
Can sizes (#/case, net wt, measure, # servings) for #10, #3, #2 1/2, #2, #300
6---6 lbs 9 oz---13 cups---20-25 12---46 oz---5 3/4 cups---12-15 24---1 lb 13 oz---3 1/2 cups---6-8 24---1 lb 4 oz---2 1/2 cups---4-6 24---14-16 oz---1 3/4 cups---3-4
Connective tissue in meat
Collagen- hydrolyzes to gelatin with heat
Elastin- resistant to heat
Fat in meat
Marbling- fat in muscle
Finish- fat cover on carcass
Pork is a good source of…
Thiamin
High calcium meat sources
fish canned with bones, oysters, shrimp
Textured vegetable protein
Made from soy protein
Adds juiciness d/t high water content
Extends number of servings –> lowers cost
Meat pirment
myoglobin
oxidizes to brown, then green
Meat aging process
Cold storage for 10 days
Enzymes degrade proteins and increase the water holding capacity –> increases tenderness
Vacuum packaging
Anaerobic –> extends shelf life
Modified atmosphere packaging
oxygen replaced with CO2 or nitrogen
Meat grading
Done at slaughter by USDA
Wholesome Meat Act of 1967- healthy at slaughter, fit for consumption
Grades: Prime, choice, select, standard
Internal meat temperatures
Pork, beef, fish: 145
Ground meats: 160
Poultry: 165
Nitrites
used to cure meats
makes them pink
Adding vinegar to meat
increases water holding capacity –> increases tenderness
Dry heat cooking methods
Used for tender cuts
Frying, broiling, roasting
Smoke point
Should be >400’F
Carry over cooking
Occurs for 10 min after meat is removed from oven
Temperature rises 15-25’F
Moist heat cooking methods
Used for less tender cuts (more connective tissue)
Braising, simmer, steam, stew
Proteolytic enzymes
Meat tenderizers, breaks down proteins
Papain (papaya), bromelain (pineapple), ficin (figs)
How to tell if a fish is fresh
Bright red gills, bright/shiny skin, firm flesh, clear eyes
surimi
purified, minced fish
used in structured seafood products
chalazae
holds egg yolk incenter of egg
Egg nutrition
80 kcal, 6g protein, 5g fat
White (11% protein), yolk (17.5% protein)
Egg grading
Use candling to judge thickness of white, location of yolk
Color and size are not part of grade
Grades: AA, A, B
Egg sizes
Weight per dozen Jumbo- 30 oz Extra Large- 27 oz Large- 24 oz Medium- 21 oz Small- 18 oz Peewee- 15 oz
Coagulation temperature
62-70’F
Egg freshness
Can store for 6 months @ 29-32’F with Grade A eggs
Fresh egg will sink in a pan of cold water
Syneresis
Liquid is released from a coagulated product
Occurs when cooked at too high a temperature or too low a temp for too long
Specific gravity
Used to compare egg foams
= Weight of given volume / weight of same volume water
Egg foams
Stabilized by acid and sugar
Room temp eggs whip more quickly d/t lower surface tension
Poaching eggs
Use high quality egg for appearance
Vinegar and salt- better shape d/t quicker coagulation
Green egg yolks
Occurs when overcooked or allowed to cool slowly
Iron from yolk + sulfur from yolk/white = ferrous sulfide
% sag
Measures tenderness of a custard
If custard is over cooked, small % sag and might crack
Egg storage
Lose CO2 --> becomes more alkaline Air space increases Whites become watery yolk flattens Absorb odors
Milk proteins
Casein (ppt at pH of 4.6 to form soft curd)
Whey (liquid that drains from the curd)- ppt with heat
Vitamins in milk
Calcium, phosphorus, riboflavin, vit A, vit D
Pasteurization
145’F for 30 min
160’F for 15 sec
Vitamin D milk
400 USP/quart added by feeding cow vit D or adding to milk
Fat content of milk
Whole = 3.7% fat 2% = 1.5-2.25% 1% = 0.5-2% Skim = <0.5%
Evaporated milk
60% H2O removed
7.9% fat
Brown color d/t caramelization of lactose in canning
Sweetened condensed milk
Evaporated whole milk with 15-18% sucrose or glucose
Dried milk
Whole milk- 26% fat, doesn’t keep well
Skim milk- 1.5% fat, does keep well
Sweet acidophilus milk
Skim milk + acidophilus bacteria
Reduces lactose
Kefir
fermented milk
Butter and margarine fat content
80%
Cream fat contents
Heavy = >36% Medium = 30-36% Whipped = 35% Light = 18-30% Sour = <18% Half and half = 10.5%
Enzyme used in cheese making
rennet
Processed cheese
blend of natural cheeses with emulsifier (disodium phosphate)
fat does not separate out
Quick cooking cereals
Disodium phosphate added –> makes them alkaline so particles swell faster
Enzyme treated
