Domain I: Principles of Dietetics Flashcards
Fruits and Vegetables
75-93% water and CHO
Calcium: orange and greens
Vitamins C, A, some B
Crispness (state of turgor) is due to
osmotic pressure of water-filled vacuoles
With increase in age
increase in hemicellulose and lignin
Soybeans
limiting amino acid is methionine
concentrates >70% protein; isolates > 90% protein
What accelerates ripening of fruits during storage?
Ethylene gas
To delay the aging in apples….
store in controlled atmosphere/reduced 02
Climacteric fruits
ripen post harvest (peaches, pears, bananas, apples, tomatoes)
Non-climacteric fruits
best when ripened before harvest (grapes, melon, citrus)
What should be washed just before serving
Berries and mushrooms
One dozen oranges will yield:
1 qt of juice
12 oranges =
32oz juice
Green pigment
Chlorophyll
Turns olive green in acid
Pheophytin
Turns bright green in alkaline
Chlorophyllin (mushy; hemicellulose has broken down)
Yellow-orange pigment
Carotenoids
Carotenoids are ____ affected by change in pH
least
Lycopene; act as
contributes to red color in tomatoes, watermelon, and overtomes in apricots; antioxidant
Red, blue, purple flavonoids
Anthocyanins
Anthocyanins are ____ affected by change in pH
greatly
Anthocyanins are ____ in water, ____ in acid, ____ in alkaline
soluble, bright red, bluish
Canned F&V grades
Grade A
Grade B
Grade C
Grade A
desserts, salads (Fancy)
Grade B
processed (Choice)
Grade C
puddings, pies (Standard)
Starch changes to ____ during storage of potatoes
sugar
Old potatoes taste ____, cook to ____ ____ because of the _____ reaction
sweeter, darker brown, Maillard
Cooking frozen potatoes
shorter cooking time than fresh d/t blanching and freezing making the potatoes tender
How to cook cauliflower
short time, covered
Broccoli in microwave
decreased time, increased retention of vitamin C, same flavor
How to cook cabbage
to minimize the development of a strong flavor, cook for a short amount of time with the lid off to let acids escape; cook in a large amount of water
10 can
6#/case
net wt: 6lbs 9oz
Measure: 12 cups
# of servings: 20-25
Myofibrils
Muscle composed of bundles of fiber
Sheet of ____ _____ holds fibers in bundles
connective tissue
Collagen
structural part of tendon that surrounds the muscle
collagen in heat
hydrolyzed to gelatin; becomes tender
Elastin
found in ligaments, cartilage; yellow.
resistent to heat, little changes in cooking
Nutritive value of pork
good source of thiamin
Nutritive value of fish canned with bones
high calcium; good for DF people
Myoglobin
main contributor to meat color
Myoglobin + oxygen
red –> brown –> green
Green color in meat
due to further myoglobin breakdown (not harmful)
Change in muscle protein d/t
enzymes which increase the water holding capacity of the muscle
What happens to when we marinate meat in vinegar?
acid and salt increases tenderness by increasing the water holding capacity of muscle
Anaerobic (sous vide) packaging
vacuum packing meat in O2-impermeable film, stored unfrozen at 0 celsius
MAP (modified atmosphere packaging)
Air is removed and replaced with CO2 and nitrogen; prevents deterioration by slowing respirations
Inspection
mandatory, done by USDA at slaughter
round purple stamp “USDA inspected and passed”
Wholesome meat act of 1967
assures that animal was healthy at slaughter and meat is fit for human consumption
Grading
voluntary; indicates quality
appears as a shield
What determines the method of cooking meat?
The cut of meat
Most tender cuts come from
the least used muscles (loin, backbone)
Least tender cuts of meat come from
the most used muscles (flank, brisket)
Temperature for roasting meat
325 F
Slow-cooked roast yields
less waste
high temperatures
increase shrinkage and toughen
When should a meat thermometer be inserted?
before cooking
Safe minimum intern temps:
Meat and fish
Ground meat
Poultry
Meat and fish 145 F
Ground meats 160 F
Poultry 165 F
Tough cuts need to be cooked to well-done because
there is more collagen that needs more time to soften
Cured meats are pink from
nitrites
What do nitrites prevent?
botulism
What allows meat to cook more evenly?
tempering
Dry heat
frying, broiling, roasting, grilling
Dry heat is used for
tender cuts of meat
Frying
desirable property of fat used in frying has a high smoke point (> 374F)
Smoke point
temperature to which fat can be heated before puffs of smoke occur
Fat with highest smoke point
Safflower oil 513
Fat with lowest smoke point
Butter 350
Monoglycerides/shortening have ___ smoke points
lower
What causes rancidity
uptake of O2 in unsaturated fatty acids
What oil is at the most risk for rancidity?
healthiest plant oils; more PUFAS
Broiling is a form of ____ heat
radiated
Moist heat
Braising, simmer, steam, stewing
Moist heat is used for
less tender cuts with more connective tissue (bottom round, chuck, brisket)
What proteolytic enzyme tenderizes meat?
Papain
How should fresh fish look?
Attached heat, bright red gills, and bright, shiny skin
Nutritive value of eggs
80 kcal, 6g protein, 5g fat, source of vitamin A, D, riboflavin
____ is more concentrated than ____
Egg yolk, egg white
____ has more protein (by weight), fat, minerals, and vitamins
Yolk
Candeling
pass the egg in front of a bright light to view contents
Grades of eggs
AA, A, B
How do you tell if an egg is fresh?
A fresh egg will sink to the bottom of a pan of cold water with a dull, rough shell
Syneresis
liquid released from a coagulated product
occurs when cooked at too high temp or too low for too long
creates a tough, watery product
____ stiffens egg white foam by _____ the production and allowing it to ____ more easily
acid, tenderizing, extend
How do egg whites at room temperature yield a larger volume?
Egg white whipped at room temp will whip more quickly a yield a larger volume due to lower surface tension
Egg yolk and emulsion
egg yolk yields a stiffer, more stable emulsion than egg whites because it has more protein (by wt)
Frozen eggs
10% sugar or salt (by wt of yolk) are added as stabilizers
Egg substitutes
are orange, lower in fat, kcal, and cholesterol
When eggs are in the fridge for too long
there is a loss of CO2 and eggs become more alkaline
Milk
3.5% complete protein
80% casein (precipitated at pH of 4.6–> forms a soft curd)
What is whey?
The liquid that drains from curd of clotted milk
Fermented milk
Cultured buttermilk (more acidic): add lactic acid bacteria to skimmed or partly skimmed milk Sweet acidophilus milk: skim + acidophilus --> decreased lactose
When using buttermilk in place of regular milk, what should you increase?
Baking soda
When heated, what happens to whey protein?
Precipitates out of bottom of the pain or surface of milk (film)
How should you prevent curdling?
Slowly add an acid and agitate; acid precipitates casein
Butter
80% milk fat
Margarine
80% vegetable oil or animal fat
Hydrolytic rancidity
uptake of water; causes flavor changes in butter (saturated fats)
Oxidative rancidity
unsaturated oils are more subject to
Heavy/thick cream
> 36% fat
Medium cream
30-36% fat
Whipped cream
35% fat
Uncured cheese
cottage cheese, cream cheese
refrigerate immediately
Cured cheese
additional whey removed, salta dded, roppened
Moisture content of cottage cheese
79% (highest)
Moisture content of mozzarella
45-55%
Moisture content of parmesan
31% (lowest)
Processed cheese
American; emulsifier added
What do quick-cooking cereals have added?
Disodium phosphate
What does disodium phosphate do?
makes cereal alkaline so particles swell faster
Graham/whole wheat flour
entire grain, freshly ground, spoils quickly d/t fat in germ
Bread (hard wheat) flour
strong gluten; 11.8% protein
All purpose (blend of hard and soft wheat) flour
less gluten, 10.5% protein
Pastry (soft wheat) flour
weaker gluten; 7.9% protein
Cake (soft wheat) flour
least and weakest amount of gluten; more starch, 7.5% protein
Functional property of gluten
gives elastic properties, forms framework, holds in leaving agent
What is gluten made from?
Gliadin and glutenin
Functional property of CO2
provides acid and alkali needed for a reaction
Mixture of baking soda
NAHCO3 provides the CO2, a dry acid (sodium aluminum sulfate reacts with soda to release CO2) and cornstarch (keeps contents dry)
Types of baking powder
SAS-Phosphate
All baking powders have
baking soda
What happens with old baking powder?
There is more alkaline which causes a loss of thiamin in baked goods
Hydroscopic affect of sugar
modifies texture by tenderizing
Sugar and gluten
softens gluten and prevents gluten development by absorbing some of the water that gluten needs
What happens when there’s too much sugar?
coarse cells, thick walls, a shiny crust, and a crumbly product
Sugar content in a low fat muffin
High
Basic ingredients of quick breads
Egg, flour
How are quick breads leavened?
Steam, air, chemical leavning agents
What happens with excess mixing?
Loss of CO2, overdeveloped gluten, tunnels, tough and heavy product
Why does the center of a cake fall in?
The more sugar, the more time needed to reach to elevated coagulation temp of gluten. So as sugar increases the volume the cake also increases to the point where the volume is so great and gluten is so weak that gluten strands snap and the cake falls in the center
Tenderness of pie crust is caused by
use of oil, soft fats or fat cut into small pieces
Flakiness of pie crust is promoted by
leaving fat in coarse particles
When substituting butter for lard
use for butter because butter is only 80% fat while lard is 100%
Sponge method of yeast dough
combine liquid with yeast and part of flour, allow to ferment for sevral hours then add sugar, salt, fat, rest of flour and knead
Proofing time of sponge method for yeast dough
shortening
Starch is composed of
amylose and amylopectin molecules
What is amylose responsible for?
Gelation
Waxy starches (corn rice, sorghum) have
amylopectin (branched fraction)
Waxy starches are
non-gelling, stable to freezing and thawing, used in frozen foods
What starch is more effective for thickening?
Potato
Gelatinization
swelling that occurs when starch is heating in water close to the boiling point
Why should you add an acid when gelatinization is complete?
Acid breaks down starch –> runny product
White sauces
melt fat, add flour (roux-half fat, half flour)
What starch should you use as a thickener to get a clear, shiny, and translucent sauce?
Corn starch
What do crystal inhibitors do?
They keep crystals small and smooth
More cyrstal inhibitors=
soft candy
Crystalline sugar
fixed, orderly pattern of molecules or atoms
Large crystals =
rock candy
Small crystals =
fondant, fudge
What ingredients does fudge have that interfere with crystallization?
Milk, chocolate, corn syrup
Ice cream overrun
increase in volume from freezing and whipping; should be 70-80% of wt
If there is not enough fat in ice cream, what texture will the ice cream have?
Grainy with large crystals
How do you produce smoother ice cream?
Increase fat
Nutritive value of Gelatin
4kca/g
Is gelatin a complete protein?
NO-missing tryptophan
Bromelain
enzyme in fresh or frozen pineapple that breaks down protein and prevents gelation
Papain
proteolytic enzyme from papaya that will prevent gelation
At what temperature should coffee be brewed at for best and non-bitter flavor?
185-203 F
What happens if you brew coffee at a high temp?
tannin is extracted –> bitter flavor
Where do you find the composition of food?
National Nutrient Data Bank from USDA
Sorbitol
humectant (retains moisture), sweetener, bulking agent, limits mold
Propionate, sodium benzoate (soda)
mold inhibitor
Monosodium Glutamate (MSG)
flavor enhancer; provides savory umani taste
Function of grape juice and red white
Resveratrol –> decreases platelet aggregation
Function of Fatty fish
omega 3 fatty acids –> reduce TG levels
Function of Tomatoes
Lycopene –> may reduce prostate cancer risk
Fermented dairy products
probiotics –> GI health
Fortified margarines
Plant sterols and stanol esters –> decrease total and LDL cholesterol
Phytochemicals
chemical compounds in plant foods
Indoles
phytochemical; cruciferous vegetables (sulfer)-detoxification of carcinogens
Isoflavones
phytochemical; soy beans-lower elevated cholesterol
