Food Science and Nutrient Composition of Foods Flashcards
WDescribe the nutritive value of fruits and vegetables.
- 75-93% water
- digestible and indigestible carbs
- some minerals (calcium in oranges, greens)
- vitamins (C, A and some B)
Calcium is in what fruits and vegetables?
oranges and greens
What vitamins are in fruits and vegetables?
C, A and some B
Crispness of fruits and vegetables is also known as what?
state of turgor
Crispness of fruits and vegetables is due to?
the osmotic pressure of water filled vacuoles
With age ___ and ____ increase in fruits and vegetables.
hemicellulose and lignin
Lignin is?
a non-CHO substance that is not significantly softened by cooking
___ is unusually complete for a plant protein.
Soybean
What is the limiting amino acid in soybeans?
methionine
Soy protein concentrates contain ___% protein.
≥70
Soy protein isolates contain ___% protein.
≥90
What is TVP?
textured protein product; end product made from processing soybeans to produce fibers
ripening is chemical changes due to ___.
enzymes
During ripening starch changes to ___.
sugar
During ripening ___ is converted to pectin (ripe) which is then converted to ___ (overripe).
protopectin; pectic acid
___ accelerates ripening of fruits during storage.
Ethylene gas
Most produce can be stored where?
Refrigerator
Store frozen fruit ___.
at or near 0° F
Store dried fruit ___.
at room temperature
___ ripen best at room temperature.
pears, bananas, avocados, and tomatoes
How is aging delayed in apples?
In a controlled/reduced oxygen atmosphere
Raw fruits and vegetables are washed to remove ___ and ___.
dust; spray residues
___ and ___ should be washed just before serving.
berries; mushrooms
Fruits low in ___ darken rapidly when cut due to ___.
vitamin C/ascorbic acid; enzymatic action
How can darkening of fruits low in vitamin C be prevented?
- Dip in citrus juice
- Add sugar before freezing
- Heat to boiling
___ oranges yields ___ orange juice.
one dozen; one quart
Cooking does what 3 things to fruits and vegetables?
- softens cellulose
- increases keeping quality
- cooks starch
When sweetener is added to liquid packing juice, the density of the syrup is expressed as ___.
% by weight of sucrose
Density of a packing syrup is measured in ___ by a ___.
degrees Brix; Brix hydrometer
Density of a packing syrup is expressed on a label as ___.
extra light, light, heavy, extra heavy
Green pigment is known as ___.
chlorophyll
Chlorophyll is soluble or insoluble in water?
insoluble
Chlorophyll turns olive green in ___ and is converted to ___.
acid; pheophytin
Chlorophyll turns bright green in ___ and is converted to ___.
alkaline; chlorophyllin
What is the texture when chlorophyll is converted to chlorophyllin?
mushy; hemicellulose is broken down
Yellow/orange pigment is known as ___.
carotenoids
How are carotenoids affected by changes in pH?
They are the least affected by changes in pH; there is little effect in an acid or alkaline solution.
Carotenoids are soluble or insoluble in water?
insoluble
Lycopenes contribute what color to what fruits and vegetables?
they contribute to the red color in tomatoes, watermelon, and overtones in apricots.
Lycopenes act as what?
antioxidant and phytochemical
Red, blue, purple, and white pigments are known as what?
flavonoids
Red, blue, and purple pigments are known as what?
anthocyanins
Anthocyanins are soluble or insoluble in water?
soluble
Anthocyanins turn bright red in ___.
acid
Anthocyanins turn bluish in ___.
alkaline
White pigments are known as what?
anthoxanthins or flavones
Anthoxanthins are soluble or insoluble in water?
soluble
Anthocyanins turn colorless in ___.
acid
Anthocyanins turn yellow in ___.
allkaline
Chlorophyll turns ___ in acid.
olive green
Chlorophyll turns ___ in alkaline.
bright green
Anthocyanins turn ___ in acid.
bright red
Anthocyanins turn ___ in alkaline.
bluish
Anthoxanthins turn ___ in acid.
colorless
Anthoxanthins turn ___ in alkaline.
yellow
Sugars are in what vegetables?
peas and corn
___ is found in young vegetables and is used in ___.
glutamic acid; in form of salt (MSG)
Glutamic acid is found in what type of vegetables?
young
Sulfur is found in what vegetables?
onions and cabbage
When cutting onions or cabbage ___ and ___ are mixed.
sulfur and enzymes
How should Brussels sprouts be cooked for the best flavor?
uncovered and with little water
The flavor of fruit is due to what?
sugar, acids, and aromatic compounds
___ causes the astringent feeling in mouth when eating fruit.
Tannins (ex under-ripe banana)
Tannins cause the ___ feeling in the mouth when eating fruit.
astringent (ex under-ripe banana)
Grades of fruits and vegetables are based on ___.
quality, firmness, color, maturity, freedom from defects. uniform size and shape
?Explain the grading of canned fruits and vegetables.
- Grade A: desserts, salads (Fancy)
- Grade B: processed (Choice)
- Grade C: puddings, pies (Standard)
?Explain the grading of fresh produce.
Fancy, Extra #1, #1, combination, #2
Who grades fruits and vegetables?
USDA
Potatoes have ___ which cause color changes in raw, peeled, or bruised potatoes.
phenolic compounds
Potatoes have phenolic compounds which cause ___ in raw, peeled, or bruised potatoes.
color changes
Green color under a potato skin is due to ___.
chlorophyll that develops when potato is exposed to light during storage; may be accompanied by solanine, a natural toxicant
Chlorophyll in potatoes may be accompanied by ___/
Solanine, a naturale toxicant
Potato starch changes to ___ during storage.
sugar
Old potatoes taste ___, cook to a ___, and are ___ in texture compared to newer potatoes
sweeter; dark brown (Maillard reaction); softer
How should you boil vegetables?
Use a small amount of salted water for a short amount of time, covered pan unless otherwise indicated- to preserve nutrients. For acidic vegetables that need more time to cook- use more water and no lid.
How should you steam vegetables?
in a perforated container, covered, over boiling water
What are the benefits of preparing vegetables in a pressure cooker?
retains color and flavor
How should you prepare vegetables prior to pressure cooking?
cut small
How should you stir fry vegetables?
use tender vegetables, high in moisture; don’t drain
**How should you frozen vegetables?
shorter cooking time than fresh because blanching and freezing have made them tender
How should you cook cauliflower?
for a short time, covered.
What are the benefits of cooking broccoli in the microwave?
less time, same flavor, retains color slightly, better retention of vitamin C, no large difference in eating quality
**How can you cook cabbage to minimize the development of a strong flavor?
cook for short time. keep lid off initially to let acids escape, cook in large amount of water
**What is the #/case, net weight, measure, and # of servings for a #10 can?
6; 6 lbs. 9 oz.; 13 cups; 20-25 servings
What is the #/case, net weight, measure, and # of servings for a #3 can?
12; 46 ounces; 5 3/4 cups; 12-15 servings
What is the #/case, net weight, measure, and # of servings for a #2.5 can?
24; 1 lb. 13 oz.; 3 1/2 cups; 6-8 servings
What is the #/case, net weight, measure, and # of servings for a #2 can?
24; 1 lb. 4 oz; 2 1/2 cups; 4-6 servings
What is the #/case, net weight, measure, and # of servings for a #300 can?
24; 14-16 oz; 1 3/4 cups; 3-4 servings
Muscle is composed of bundles of fibers called ___.
myofibrils
___ holds fibers in bundles.
a sheet of connective tissue
**Muscle contains 2 proteins called ___ and ___.
collagen; elastin
**What happens to collagen in heat?
It is hydrolyzed to gelatin and becomes tender/softens
**What is collagen?
The structural part of tendon that surrounds muscle
**Where is elastin found?
found in ligaments, cartilage; yellow color
**What happens to elastin in heat?
resistant to changes in heat, there is little change during cooking
What is finish?
the amount of fat cover on carcass
Where can you find fat in meat?
deposited around organs, muscles, in muscles
What is it called when you find fat in muscles?
marbling
The shape of bone identifies the ___.
cut
Round bone is from the ___.
leg
T-bone is from the ___.
back and ribs
Meat is ___% protein.
16-23%
Where would you find carbohydrates in meat?
- glycogen in the liver
- glucose in blood
What are vitamins and minerals found in meat?
thiamin, niacin, riboflavin, iron, copper, and trace minerals
**Pork is a good source of ___.
thiamin
Fish has less ___ and more ___ than meat. It also has fewer ___.
fat; moisture; calories
**___ content is high in fish canned with ___, ___, ___.
calcium; bones; oysters; shrimp
What is TVP?
textured vegetable protein; fabricated into simulated meat products
What are benefits of mixing TVP with ground meats?
It extends the number of servings thus lowering costs and adds juiciness because of water content
What is the main contributor to meat color?
Myoglobin
Myoglobin + oxygen –> ___ ->___->___
red; brown; green with further oxidation of myoglobin
**What are green colors in meat due to?
further myoglobin breakdown/oxidation
Where and how long should meat be aged and ripened?
held in cold storage; about 10 days
How does aging meat increase the tenderness?
Enzymes bring about a change in muscle proteins which increases the water holding capacity of muscles
___ and ___ also increase tenderness of meat by increasing water holding capacity of muscle.
acid (vinegar) and salt
Physical activity of animal will or will not increase tenderness?
will not
**How can the storage life of meat be extended?
vacuum-packing meat in an oxygen-impermeable film, stored unfrozen at 0°C is anaerobic (sous vide)
What is modified atmosphere packaging?
MAP, air removed and replaced with gases (carbon dioxide and nitrogen)
For meat, the method of cooking is determined by what?
the cut of meat
Dry heat is used for what cuts of meat?
tender; near backbone; loin, sirloin
What are dry heat cooking methods?
frying, broiling, roasting
What is a desirable property of fat used in frying?
high smoke point
Define smoke point.
temperature to which fat can be heated before puffs of smoke occur
What should the smoke point be for fat used in frying?
> 400° F
Should frying be used for tough cuts of meat such as bottom round?
no
What does rancidity involve?
the uptake of oxygen in an unsaturated fatty acid
What is broiling?
form of radiated heat
During which method of dry cooking does carry-over cooking occur?
roasting
What is carry-over cooking?
when meat is removed from the oven the internal meat temperature will rise 15-25° F; occurs for about 10 minutes
For about how long does carry-over cooking occur?
10 minutes
A roast should stand how long before carving?
30 minutes
Moist heat is used for what cuts of meat?
less tender cuts with more connective tissue; bottom round, chuck, brisket
What are moist heat cooking methods?
braising, simmer, steam, stewing
How should a bottom round be cooked?
in water for several hours
What is braising?
a moist heat cooking method in which you flour the meat, brown, cover and simmer in liquid
Where in the oven is braising done?
in the oven or on top of the range
What is simmering?
A moist heat cooking method in which water is heated to 170-185° with appearance of bubbles
What is steaming?
A moist heat method in which meat is heated over, not in, water
What is stewing?
a moist heat cooking method in which water or other liquid is added during cooking
Proteolytic enzymes do what to meat?
tenderize
What is an example of a proteolytic enzyme used to tenderize meat?
Papain (from papayas)
What method of cooking should be used when cooking fish?
dry or moist heat
Fish is more ___ than meat so it should be stored at a ___ temperature.
perishable; lower
How should fresh fish with the head attached look?
- bright red gills
- bright, shiny skin
- firm flesh that springs back when touched
If fresh fish with the head attached do not have bright red gills, bright, shiny skin, and firm flesh that springs back when touched- what should you do?
reject it
Describe the look of a fish with the head attached that should be rejected.
- gills are dull and grey
- cloudy, red-rimmed, sunken eyes
- soft texture leaving an imprint when pressed
What is surimi?
purified and frozen minced fish with a preservative, used in analogs, may have egg white or starch added to create desired structure
Surimi is used in what?
structured seafood products; crab and shrimp analogs
Is the shell of an egg porous or non-porous?
porous
What is the purpose of an egg’s porous shell?
to exchange moisture and gases; covered with a bloom that prevents excessive loss and protects contents
What the purpose of the bloom inside and egg?
prevents excessive loss and protects contents
Is the color of an egg shell related to the food value or quality?
no
the inner membrane of the egg contracts and leaves airspace in what end?
the large end
The air space in an egg becomes ___ with age.
larger
What is a good quality indicator for eggs?
high proportion of thick white
What is the yolk of an egg surrounded by?
vitelline membrane
What are chalazae?
yolk anchors; hold the yolk in the center of an egg
Egg yolk is a naturally occurring ___.
oil in water emulsion
What is the nutritive value of an egg?
- 80 calories
- 6 grams protein
- 5 grams fat
- vitamins A, D
- riboflavin
the ___ of an egg is more concentrated than the ___.
yolk; white; has more protein (by weight), fat, vitamins, minerals
In an egg, ___ is present in an emulsified form.
fat
In an egg, fat is present in an ___ form.
emulsified
The color of an egg yolk depends on ___.
amount and type of pigment in the hen’s diet
What is candling?
Passing an egg in front of a bright light to view its contents
What is judged during the candling process of an egg?
- thickness of white
- location and condition of yolk
What does (egg) grading not include?
- color of the shell
- size of the egg
What are the grades of eggs?
AA, A, B
Is size a part of the grading of an egg?
no
How is egg size classified?
on basis of weight per dozen: - jumbo 30 oz
- extra large 27 oz
- large 24 oz
- medium 21 oz
- small 18 oz
- peewee 15 oz
How long can the freshness of an egg be maintained?
6 months in cold storage (29-32° F) with grade A eggs
A ___ egg will sink to the bottom in a pan of cold water and has a ___ shell.
fresh; dull, rough
At what temperature does an egg coagulate?
62-70° C (sets a custard)
Egg coagulation is used to do what?
- bind
- give firmness, stability
- coats food
- browns
- clarifies liquids
What is syneresis?
weeping; liquid released from a coagulated product
When does syneresis occur?
when eggs are cooked at too high a temperature, or too low a temperature for too long a time; protein contracts and squeezes out liquid leaving tough, solid protein mass
What type of product does syneresis create?
tough, watery
Effectiveness of leavening depends on what?
amount of air beaten in and retained
What is leavening?
when an egg foam is heated, air expands, egg white stretches and protein coagulates leaving a light porous product
What does an acid do to an egg white foam?
stiffens
How does an acid stiffen an egg white foam?
by tenderizing the protein and allowing it to extend more easily
How are egg white foams compared?
by measuring the specific gravity
What does specific gravity measure?
the relative density of a substance in relation to that of water
How do you calculate specific gravity?
weight of given volume divided by weight of same volume of water
Egg whites at ___ temperature whip more quickly and yield a larger volume due to lower surface tension.
room
Egg whites at room temperature whip ___ and yield a ___ volume due to ___ surface tension.
more quickly; larger; lower
What stabilized an egg white foam?
sugar
What is emulsification?
protein in egg forms a thin film around droplets of oil; stabilizes emulsion
Why does an egg yolk yield a stiffer, more stable emulsion than an egg white?
it has more protein (by weight)
Does an egg white or an egg yolk form a stiffer more stable emulsion?
egg yolk
yolk is a naturally occurring ___.
emulsion
what is mayonnaise?
food emulsion stabilized by egg yolk
Explain the emulsion of an egg yolk.
- lecithin helps the yolk act as an emulsifier
- lipoproteins stabilize the emulsion by interacting at the surface of the oil droplets to form a layer
What helps the yolk act as an emulsifier?
lecithin
What stabilizes the emulsion of an egg yolk and how?
lipoproteins; interact at the surface of the oil droplets to form a layer
What are methods of cooking eggs?
- water preparation
- dried heat
- custards
When poaching or coddling, what type of egg do you want to use?
high quality egg; appearance is important
___ and ___ improve the shape of a water prepared egg by hastening coagulation.
Vinegar; salt
Vinegar and salt improve the shape of a water prepared egg by ___.
hastening coagulation
During water preparation, the surface of the yolk turns green when ___ or ___.
overcooked; allowed to cool slowly
What causes the yolk to turn green when overcooked or allowed to cool too slowly?
- combination of iron from the yolk and sulfur from the whole egg
- combination creates ferrous sulfide
When using dried heat to cook an egg what happens when the egg is overcooked?
egg toughens
When using dried heat to cook an egg what happens when the egg is undercooked?
excessive shrinkage when removed from the oven
With custards, the larger the % sag, the more ___ the gel.
tender
With custards, the larger ___ the more tender the gel.
the % sag
In custards, % sag is an objective measure of what?
objective measure of quality
What can happen to custards made from dehydrated eggs?
- may be grayer and less yellow
- have an eggy flavor
- be watery
What are forms of processing eggs go through?
- frozen
- dried
- egg substitutes
What is added to frozen egg yolks as stabilizers?
salt and sugar
How are eggs frozen?
removed from shell first, can be frozen whole or in parts
dried eggs can vacuum packed in ___.
nitrogen gas
dried fortified eggs are ___% white and ___% yolk
70%; 30%
What are baker’s special eggs?
sucrose is added to improve foaming ability
egg substitutes are ___ in fat, calories, cholesterol; often ___ in sodium
lower; higher
egg substitutes are lower in ___; often higher in ___
fat, calories, cholesterol; sodium
when cooking with egg substitutes, there will be ___ and ___ differences
color; flavor
What happens when eggs are held in the refrigerator for too long?
- deterioration affects appearance and use
- loss of carbon dioxide makes eggs more alkaline
- whites become watery; yolks flatten
- odors are absorbed
What is the nutritive value of milk?
- 87% water
- 3.7% fat
- 4.9% CHO (lactose)
- 3.5% protein (complete HBV)
what is the main carbohydrate in milk?
lactose
Describe the protein in milk.
complete, HBV; 80% casein
80% of milk protein is ___
casein
casein precipitates at a pH of ___ and forms ___
4.6; soft curds
___ is liquid that drains from curd of clotted milk
whey
Milk is a good source of ___
- calcium
- phosphorus
- riboflavin
- vitamins A & D
Milk is low in ___
iron
Pasteurization does what to milk
destroys pathogenic bacteria
Describe the time and temp for milk pasteurization
- 145° F for 30 minutes OR
- 160°F for 15 seconds
What are the types of milk
homogenized, vitamin D, 2%, low fat, skim, concentrated, fermented, low lactose, yogurt, filled milk, imitation milk
How is homogenized milk made?
high pressure breaks fat globules to 1/5 the regular size; film of protein surrounds each globule
Homogenized milk is more susceptible to the action of ___
lipase, but the pasteurization process destroys lipase
How is vitamin D milk made?
400 USP units added per quart of milk by feeding the cow vitamin D, irradiating the milk, or adding the vitamin; must be labeled “vitamin D milk”
2% milk has ___% fat?
1.5-2.25%
low fat milk has ___% fat?
.5-2% fat
skim milk has ___% fat?
< .5% fat
List the types of concentrated milk
evaporated, sweetened condensed, dried whole, dried skim
What is evaporated milk?
60% water is removed
Evaporated milk must contain ___% milk-fat
no less than 7.9%
What is the brown color of evaporated milk due to?
carmelization of lactose in canning
What is sweetened condensed milk?
concentrated evaporate whole milk; add 15-18% sucrose or glucose
For sweetened condensed milk ___% sucrose or glucose is added?
15-18%
Does dried whole milk keep well?
no
dried whole milk is ___% fat?
26%
dried skim milk is ___% fat?
no more than 1.5% fat
does dried skim milk keep well?
yes
how is condensed skim milk made?
dry by spraying into a heated vacuum chamber
What are the types of fermented milk?
- cultured buttermilk
- sweet acidophilus milk
- kefir
How is cultured buttermilk made?
add lactic acid bacteria to skimmed or partly skimmed milk
What is the recipe for cultured buttermilk?
1 T vinegar or lemon juice, or 1 3/4 tsp cream of tartar; add enough milk to make 1 cup
when using buttermilk in place of regular milk in a recipe, ___
increase the baking soda
What is sweet acidophilus milk?
skim milk plus acidophilus bacteria which reduced lactose
What is kefir?
fermented by Lactobacillus kefir; adds carbon dioxide; about 3% alcohol
By fermenting with lactobacillus to make kefir ___ is added
carbon dioxide
kefir is ___% alcohol
3%
what is low lactose milk and how is it made?
lactaid; treated with lactase in processing or add the enzyme to regular milk and hold in the refrigerator
What is yogurt and how is it made?
a coagulated milk product; fermentation of milk sugars by lactic acid bacteria
What is filled milk?
skim milk, vegetable fat (coconut oil), and water; it is illegal in some states
What is imitation milk?
it resemble milk but contains NEITHER milk fat nor other important dairy ingredients
What is imitation milk made from?
casein derivatives or soybean protein and vegetable oils
When milk is heated, ___ precipitates out on the bottom of the pan or on the surface of milk
whey protein
When milk is ___, whey protein precipitates out on the bottom of the pan or on the surface of milk
heated
what can be done to prevent a film from forming when heating milk?
cover or beat the milk to produce a foam
What can be done to prevent milk from coating the sides of pan when heating milk?
heat over water
what can be done to prevent curdling when heating milk?
add an acid slowly and agitate
in milk, an ___ precipitates casein
acid
in milk, an acid precipitates ___
casein
what is the nutritive value of butter?
80% milk fat
what is the nutritive value of margarine?
80% vegetable oil or animal fat
butter turns ___ as it takes up oxygen and releases hydrogen
rancid
butter turns rancid as it ___ and ___.
takes up oxygen and releases hydrogen
what is the % fat in heavy or thick cream?
> 36% fat
what is the % fat in medium cream?
30-36% fat
what is the % fat in whipped cream?
35% fat
what is the % fat in light or thin cream?
18-30% fat
what is the % fat in sour cream?
> 18% fat
What is the percent fat in half and half?
no less than 10.5% fat
What is the percent fat for the following? a. heavy or thick cream b. medium cream c. whipped cream d. light or thin cream e. sour f, half and half
a. >36% fat
b. 30-36% fat
c. 35% fat
d. 18-30% fat
e. >18% fat
f. no less than 10.5% fat
How is cheese produced?
with warm milk, add lactic acid bacteria, add enzyme rennet to coagulate casein forming the curd, separate curd from whey (liquid)
What are types of cheese?
uncured, cured, processed
Uncured cheese is ___ immediately.
refrigerated
What are examples of uncured cheese?
cottage cheese and cream cheese
How is cured cheese made?
additional whey is removed, salt added, ripened
List the following by % moisture content from high to low: cream, mozzarella; cottage; Camembert, bleu, Swiss, cheddar, Gorgonzola, Parmesan
- cottage (79% moisture)
- cream, mozzarella (45-55% moisture)
- Camembert, bleu, Swiss, cheddar, Gorgonzola, Parmesan (31% moisture)
What is the % moisture of cottage cheese?
79%
What is the % moisture of cream and mozzarella cheeses?
45-55%
What is the % moisture of Camembert, bleu, Swiss, cheddar, Gorgonzola, Parmesan cheeses?
31%
What is processed cheese?
blend of several natural cheeses
how is processed cheese made?
an emulsifier is added
What emulsifier is added to make processed cheese?
disodium phosphate
Why is processed cheese better for cooking?
the fat will not separate out
Is processed or natural cheese better for cooking?
processed
What is the % moisture of processed cheese?
41-50%
the starchy endosperm of grains and cereals is rich in ___.
protein
grains and cereals have an outer layer of ___ and ___
hull and bran
what is scutellum?
in the germ of grains and cereals; has most of the thiamin
the scutellum has most of the ___ in grains and cereals
thiamin
what is the nutritive value of grains and cereals?
- 75% starch
- partially complete protein
- 2% fat-found in the germ
- vitamin E, thiamin, riboflavin, phosphorus
Where is the fat found in grains and cereals?
in the germ
where is the vitamin E found in grains and cereals?
in the germ
what is milling grains?
air classification is a separation method that improves baking qualities by separating large four particles from fine particles
What do quick cooking cereals have added?
disodium phosphate
What is farina?
inner portion of a wheat kernel
Why is disodium phosphate added to quick cooking cereals?
makes the cereal alkaline so that particles swell faster
What type of diet should avoid quick cooking cereals?
low sodium due to the added disodium phosphate
what does enzyme treated for quicker cooking time mean?
the proteins have been split to lessen the cooking time
List the types of wheat flours
graham/whole wheat, bread (hard wheat), all-purpose (blend of hard and soft), pastry (soft wheat), cake (soft wheat), enriched, instant, self-rising
What is graham or whole wheat flour?
entire grain is used; use freshly ground, spoils more quickly due to the fat in the germ
What is bread flour?
made with hard wheat; stong gluten 11.8% protein
What is all-purpose flour?
blend of hard and soft wheat; less gluten; 10.5% protein
What is pastry four?
soft wheat, weaker gluten; 7.9% protein
What is cake flour?
soft wheat, least and weakest gluten; 7.5% protein
What is enriched flour?
flour enriched with thiamin, riboflavin, niacin, iron, and folic acid
What is instant flour?
no pre-sifting is needed; aka instantized, agglomerated, instant blending
What is self-rising flour?
has baking powder, flour, and salt
List the following types of flour from most to least protein: pastry, all purpose, cake, bread
- bread (11.8% protein, strong gluten)
- all-purpose (10.5% protein, less gluten)
- pastry (7.9% protein, weaker gluten)
- cake (7.5% protein, least and weakened gluten)
What is durum wheat?
high in gluten so products are flexible after cooking; after bran and germ are removed starch is ground to make semolina flour
Noodles contain ___ or ___
egg yolk or egg solids
What happens when rice is cooked in excess water or when water is drained off?
vitamins are lost
How should rice be prepared?
cook in an amount of water that will be absorbed during cooking; for 1 cup rice use 2 cups water
What is the functional property of gluten in flour?
gives elastic properties, forms framework, holds in leavening agent
How is gluten made?
from gliadin and glutenin through process of hydration and mixing
What is the color of flour due to?
carotenoids
What turns flour from creamy yellow to white?
natural agents cause oxidation during storage
What does a flour label say if an oxidizing agent is added to it?
bleached
what does strength of flour refer to?
capacity to retain leavening
what does strength of flour depend on?
quality of gluten
___ flour is strong; ___ flour is weak
bread; cake
adding ___ decreases volume of the end produce.
bran
adding bran ___ the end produce.
decreases the volume; bran is heavy and weighs the mixture down
How should you compensate if bran is added?
increase flour and liquid; flour provides more gluten and liquid hydrates
what is the functional property of liquid when using flour?
- hydrates the gluten and starts its development
- starts action of chemical leavening agent
- dissolves the salt and sugar
- gelatinizes the starch
Define leavening agent
substance causing expansion of doughs and batters by the release of gases within such mixtures, producing baked products with porous structure. Such agents include air, steam, yeast, baking powder, and baking soda.
How is steam used as a leavening agent?
it expands the hollow shell formed by flour and egg
What is required for steam to be a leavening agent?
hot oven to raise liquid to boiling quickly
Steam is used as a leavening agent in what items?
popovers and creampuffs
How is air used as a leavening agent?
expands when heated before proteins coagulate and retain it
How is air incorporated when using as a leavening agent
beating, sifting, folding, and creaming
Air is used as a leavening agent in what items?
angel cake, sponge cake
How is carbon dioxide used as a leavening agent?
from action of yeast on sugar, yielding carbon dioxide and alcohol; from action of acid on baking soda; in baking powder
How is carbon dioxide created from the action of yeast on sugar so it can be used as a leavening agent?
that action of yeast yields carbon dioxide and alcohol
What are some acids used on baking soda to create carbon dioxide for leavening?
sour milk, cream of tartar, molasses
What is baking powder?
a mixture of baking soda (provides carbon dioxide), a dry acid (react with soda to release carbon dioxide), and cornstarch (keeps contents dry)
What are the types of baking powder?
- tartrate
- phosphate
- combination
Use __tsp baking powder per cup flour
1 1/2 tsp
What happens to old baking powder?
it becomes more alkaline causing loss of thiamin in baked goods
What is the function property of salt in breads?
- adds flavor
- keeps yeast from sticking
What happens when too much salt is added to bread?
it interferes with the growth of yeast
What is the functional property of egg in a bread?
- provides stability
- retains leavening agent
- distributes shortening by emulsification
- introduces air
- adds color and flavor
What is the functional property of fat in a bread?
adds tenderness by coating gluten particles keeping them from becoming one mass
What does it mean that sugar is hygroscopic?
softens gluten and prevents gluten development by absorbing some of the water that gluten needs this modifies the texture by tenderizing
What does too much sugar in a bread result in?
coarse cells, thick walls, a shiny crust and a crumbly product
What is most of the sugar in honey?
glucose and fructose
When substituting sweet and low for sugar in a recipe how much should you use?
half as much
list methods of mixing
beat, cream, cut-in, fold, knead, stir, and whip
What is the beating method of mixing?
mixing over and over to smooth and incorporate
What is the creaming method of mixing?
work one or more foods until soft and creamy; ex. cream fat into sugar
What is the cut-in method of mixing?
distribute fat into dry ingredients
What is the fold method of mixing and when is this used?
a down, across, up and across the top motion, rotate the bowl; used in foams
What is the knead method of mixing and when is it used?
push, pull, turn; used in doughs
What is the stir method of mixing?
circular or figure eight motion to blend
What is the whip method of mixing?
beat rapidly to incorporate air to form a foam
What type of bowl should be used for mixing and how full should that bowl be?
a bowl with sloping sides; 1/2 full
What are quick breads?
they are leavened with steam, air, chemical leavening agents
What are examples of quick breads?
muffing, biscuits, and popovers
What are the basic ingredients of a quick bread?
egg and flour
What is the muffin method of mixing?
- sift dry ingredients; make well in the center
- blend liquids and add all at once to dry
- mix just enough to dampen; DO NOT want a smooth batter
What happens with excess mixing of muffins?
- loss of carbon dioxide
- overdeveloped gluten
- tunneling from top to bottom
- tough, heavy product
What are the characteristics of a good muffin?
- round, pebble top
- symmetrical shape
- no long, narrow tunned
What is the method of mixing cakes?
- cream fat with sugar
- add egg
- add sifted dry ingredients in portions alternating with portions of milk
What are two types of cake, with examples of each
- shortened cake (layer, pound)
2. foam cake (angel, sponge, chiffon)
Describe shortened cakes
comparatively large amount of fat; uses chemical leavening
What is the leavening agent in a layer cake?
baking powder
What is the leavening agent in a pound cake?
air from creaming and steam during baking
For a rich cake, increase ___, ___, and ___; this ___ the keeping quality
fat; sugar; egg; increases
to make a gold cake, use ___.
egg yolks
to make a white cake, use ___.
egg whites
to make a yellow cake, use ___.
the whole egg
foam cakes use ___ as the leavening agent
air
an angel cake used ___ foam
egg white
a sponge cake uses ___ foam
yolk and white foam
a chiffon cake uses what?
liquid yolks, egg white foam, baking powder (leavening agent) and oil (liquid)
What does crumb structure depend on?
ingredients, procedure used, pan shape and size, baking temperature, time elapsed before baking
the more sugar, the ___ time is needed to reach the elevated coagulation temperature of the gluten
more
as sugar ___, the volume of the cake increases up to the point where the volume is so great, and the gluten so week, that the gluten strands snap and the cake falls in the center (gummy crystalline center)
increases
Why might a cake fall in the center due to excess sugar?
volume of cake increases, volume is great and gluten weak so the gluten strands snap; this gives a gummy crystalline appearance
What causes yellowing in cakes?
alkaline batter (excess soda)
What causes a fallen center in cakes
excess sugar, excess fat, excess baking powder, inadequate mixing, oven temp too low, open door early during baking
What causes a tough, dry crumb in cakes?
too much flour or egg, too much mixing, too little fat or sugar, over-baking
What causes a coarse texture in cakes?
too much baking powder or sugar, oven temp too low, inadequate mixing
What causes poor volume in cakes?
too little baking powder, improper level of sugar or fat
What are cookies?
modified shortened cake; higher in fat, lower in sugar and liquid
What is a pastry made of?
flour, fat, liquid, and salt
lard and oil are ___% fat?
100%
butter and margarine are ___% fat?
80%
When substituting butter for lard, do you use more or less?
more because butter is only 80% fat while lard is 100%
When substituting oil for lard, do you use more or less?
use equal amounts because they are both 100% fat
What is the mixing method for pastries?>
- cut fat into flour and salt
- add liquid
avoid overhandling
bake at 425-450°F for 10-15 min
at what temp and for how long should pastry dough be baked?
bake at 425-450°F for 10-15 min
How can you enhance tenderness in pie crusts?
by using oil, soft fats, or fat cut into very small pieces
How is flakiness in pastries promoted?
leaving fat in coarse particles; fat in pieces melts and flows, leaving a hole where steam collects and pushes upward against the upper surface of the resulting cell, the cell is locked into that extended position resulting in a flaky crust
How should a meringue be added to a pie
spread meringue on warm to hot filling and bake at 425°F for 4-5 min
put the following doughs in according to proportion of flour to liquid: drop, stiff, pour, soft
- pour (1:1 liquid:flour; waffles)
- drop (1:2 liquid:flour; muffins)
- soft (1:3 liquid:flour; bread)
- stiff (1:4 liquid:flour; pie crust)
what is an example of a pour dough
waffle
what is an example of a drop dough
muffin
what is an example of a soft dough
bread
what is an example of a stiff dough
stiff
a ___ fat, ___ sugar batter absorbs most fat when deep fried
more fat; more sugar
a more fat, more sugar batter absorbs most fat when ___
deep fried
What type of flour should be used for yeast dough
high protein bread flour
What happens if low protein bread flour is used for yeast dough
crumbly products with poor texture
What does the yeast ferment in a yeast dough and what is the product?
sugar; releases carbon dioxide
what are methods of producing a yeast dough?
straight dough, sponge method, and continuous bread making method
What is the straight dough method for preparing yeast dough?
all ingredients are added before dough is allowed to ride
What is the sponge method for preparing yeast dough?
- combine liquid with yeast and part of flour and allow this batter (sponge) to ferment for several hours
- add sugar, salt, fat, and rest of flour
- knead
- proofing time is shortened
use strong flour, high in protein (bread flour)
what is proofing time?
the final rising of the dough
what is the sponge of a yeast dough prepared with the sponge method?
batter made with the liquid, yeast, and part of the flour
what type of flour should be used for the sponge method of mixing yeast dough
strong, high protein, bread flour
In what setting is the sponge method of mixing yeast dough used?
commercial
What is the continuous bread making method for preparing yeast doughs?
commercial process that substitutes intense mechanical energy to a large degree for traditional bulk fermentation
What is the benefit of continuous bread making as a method for preparing yeast doughs?
reduces processing times; not as affected by fermentation time and temperature
In what setting is the continuous bread making method of mixing yeast dough used?
commercial
What happens when baking at high altitudes?
decreased pressure causes gas to expand faster, steam forms earlier; expansion may be excessive before heat of oven has coagulated the protein and gelatinized the starch enough to stabilize the structure
How should you correct when baking at high altitudes?
- decrease amount of baking powder
- increase the amount of liquid
starch is composed of ___ and ___ molecules
amylose and amylopectin
___ is responsible for gelation in cooled, cooked pastes
amylose
amylose is responsible for ___ in cooled, cooked starch pastes
gelation
___ starches have only amylopectin
waxy (corn, rice, sorghum)
Waxy starches have only ___
amylopectin
what are examples of waxy starches?
corn, rice, and sorghum
is amylopectin gelling or non-gelling?
non-gelling
Are waxy starches stable to freezing and thawing or not?
yes, they are stable
waxy starches are used in what types of food
frozen
what type of starch is used most often?
corn
list the thickening ability of the following starched in order of effectiveness: waxy sorghum, waxy rice, potato, waxy corn, wheat, tapioca
- potato
- waxy corn
- waxy rice
- waxy sorghum
- tapioca
- wheat
why is wheat flour even less effective tha pure wheat starch?
because of the protein content
What is the most effective starch to use as a thickener?
potato; can use the least amount
___ starches are more effective thickening agents in starch pastes than their standard counterparts
waxy
waxy starches are more or less effective thickening agents in starch pastes than their standard counterparts?
more
___ and ___ flour have more starch and less gluten so they thicken better
pastry and cake
pastry and cake flour have more ___ and less ___ so they thicken better
starch; gluten
what is gelatinization?
the swelling that occurs when starch is heated in water close to the boiling point; heat dissociates the bonds so that water moves in and swells granules; friction is created causing the paste to thicken
What is the role of sugar in starch pastes?
1) competes with starch for the water needed for gelatinization
2) increases translucency, reduces viscosity and gel strength
what happens to a starch paste if too much sugar is added?
the consistency is thin; the water used to dissolve excess sugar and is no longer available for the gelatinization of the starch- this decreases the swelling of the starch granules
why is an acid added when cooking of starch paste is complete?
acid breaks down the starch and will give a runny product if added any sooner (ex. if lemon juice is added to lemon meringue pie before cooking is complete the filling will be runny)
what is retrogradation?
after a starch paste has been cooled or chilled, it may become less soluble and recrystallizes to form a solid or rigid gel; it reverts back to insoluble form on freezing or aging; the hydrogen bonds holding the gel together break and reform in an orderly crystalline fashion; recrystallization=retrogradation
retrogradation occurs in what starches?
those with a high proportion of amylose
when does a starch paste retrograde?
on freezing or aging
Why does a starch paste have a grittytexture after retrogradation?
hydrogen bonds holding the gel together break and reform in an orderly crystalline fashion
What is the texture of something that has retrograded?
gritty
does retrogradation increase or decrease the quality of food?
decrease; it is undesirable
What can be done to allow something that has retrograded to move into a gel again?
heat breaks the 4 bonds holding the amylose together and allows it to move into a gel again
How can frozen products be prepared to avoid retrogradation?
prepare them with a starch or flour from a waxy cereal (waxy corn, sorghum, or rice)
Why is retrogradation greatly accelerated by freezing?
when a starch gel is thawed, water is lost because it is unable to rebind to the fragile spongy mass
What is chemical modification of a starch?
modification by acids and enzymes to change viscosity and ability to gel
What is physical modification of a starch?
starch is pre-gelatinized and dehydrated so that it is porous and no heating is needed; used in instant pudding
what is used to stabilize heated gravies?
waxy maize; modified cornstarch
How are starches prepared?
with dry heat, with moist heat, in white sauces
What is happens when dry heat is applied to starch?
- color change occurs (toast browns)
- in gravy, starch is heated without water and the temp rises rapidly degrading the starch, the starch molecules then break into fragments called dextrins (dextrinization)
What do starch granules do in cold water?
form a suspension; they DO NOT dissolve
What happens when moist heat is applies to starch?
when heated, molecules swell, thicken, become translucent due to gelatinization
What happens when starch is not mixed well enough with the cold liquid or is added directly to hot liquids?
lumps form which decreases thickening; granules on the outside swell as they take up water; those on the inside remain dry, decreasing thickening
How can lumps be prevented when applying moist heat to starches?
mix starch with fat, cold liquid or sugar
What affects the stability of swollen starch granules in a paste?
- heat
- acid
- agitation
How are white sauces made?
- melt fat, add flour
- remove from heat, add liquid at 170-180° F; add salt
- add an acid when cooking is complete
What is a roux?
half fat, half flour
How can you get a clear, shiny, translucent white sauce?
use cornstarch as a thickener
What is a grainy and starchy tasting produce due to when cooking a white sauce?
uncooked flour
what is an example of a thick white sauce?
souffle
How do you prepare crystalline candies?
- heat sugar and liquid to dissolve; heat further
2. crystallize under conditions that produce small crystals which have a smooth, creamy feeling
How can crystal size be controlled?
- acid (cream of tartar, vinegar)
- fat (chocolate, milk)
- protein (milk, egg whites, gelatin)
- other
What are means of controlling crystal size other than acid, fat, and protein?
- dissolve all sugar
- allow no dust particles to remain on surface during cooling
- cool until viscous before agitation
- continuous agitation
What are the ingredients of candies?
sugar, water, corn syrup or cream of tartar
What is the product like when making candies? How does this change during the process? with further beating?
viscous, shiny, and smooth at the start of the process; then becomes creamy, dull, and lighter in color; with further beating cools and stiffens rapidly
What are the two types of candies?
crystalline sugar and non-crystalline suga
What is crystalline sugar?
has a fixed orderly pattern of molecules or atoms
What is an example of large crystalline crystals?
rock candy
What is an example of small crystalline crystals?
fondant or fudge
Why is fudge creamier than other crystalline candies?
it has more substance that interfere with crystallization
Describe non-crystalline candies.
amorphous, glasslike
How is crystallization prevented in non-crystalline sugar candies?
by adding interfering substances (fat, milk) or by increasing the concentration of sugar
What can be added to retard crystallization thus increasing viscosity and chewiness?
corn syrup
give examples of the following non-crystalline candies:
a. hard candies
b. brittles
c. chewy candy
d. gummy candy
a. hard candies: sourballs, butterscotch
b. brittles: peanut brittle
c. chewy candy: taffy, caramel
d. gummy candy: marshmallows, jellies, gumdrops
What is overrun?
the increase in volume from freezing and whipping
How is overrun determined?
by weight; shouldx be 70-80%
Overrun in ice cream should be ___%
70-80%
What makes ice cream smooth and how?
homogenization; makes it easier to beat in air during freezing
What is essential to keep ice crystals small and to incorporate air when making ice cream?
agitation
Why is agitation essential when making ice cream?
it keep ice crystals small and incorporates air
when making ice cream, what type of water should you hydrate gelatin in?
cold water, then heat
when making ice cream ___ interferes with crystal formation, making crystal small and smooth
fat
What is the product if not enough fat is added when making ice cream?
a grainy ice cream with large crystals
If your ice cream is grainy, how can you produce a smoother ice cream?
increase the fat (use whipping cream v half and half or heavy cream instead of light cream)
Aside from fat, what are other things that interfere with crystallization when making ice cream?
egg, gelatin, nonfat milk solids also interfere with crystal formation
what is mellorine?
imitation ice cream; butterfat is replaced by hydrogenated vegetable oil
what is the nutritive value of gelatin?
4 calories per gram; it is an incomplete protein
why is gelatin considered an incomplete protein?
no tryptophan, low in methionine and lysine
what are properties and uses for gelatin?
- changes liquid into an elastic solid
- acts as a foaming agent (ex marshmallows)
- keeps sugar and ice crystals small in candy and ice cream
how does gelatin keep sugar and ice crystals small in candy and ice cream?
interferes with the union of small crystals to make larger ones
describe the process of gel formation
1 T gelatin will gel 1 pint liquid; mix with cold water to soften; add hot water to disperse
1 T gelatin will gel how much liquid?
1 pint
what adjustments should be made when making a large gelatin mold, when gel is standing at room temperature for a long time, when acid content is high, or when making a whip?
increase gelatin or decrease liquid
when making a gel when should you increase the gelatin or decrease the liquid?
- when making a large gelatin mold
- when gel is standing at room temperature for a long time
- when acid content is high
- when making a whip
what is bromelin?
an enzyme in fresh or frozen pineapple that breaks down protein and prevents gelation
what enzyme in fresh or frozen pineapple breaks down protein and prevents gelation
bromelin
where is bromelin found?
in fresh or frozen pineapple
brew coffee at ___°F for the best flavor
185-203°F
What happens when coffee is brewed above 185-203°F?
tannin is extracted and coffee is bitter
what is a percolator?
single container, covered basket with stem, gives stronger and bitter coffee; water is hotter and repeatedly passes through the grounds
What is a dripolator?
three separate compartments; add boiling water to top and let drip through; brief contact with the grounds; free of bitterness
what does vacuum brewed mean?
higher temps than recommended
What does the process of making decaffeinated coffee use?
methylene chloride
who regulates the composition of food?
national nutrient data bank, usda
who controls food additives?
FDA
list additives that are emulsifiers
- monoglycerides
- diglycerides
- lecithin
- disodium phosphate
What is the function of the additive glycerol monostearate?
humectant (retains moisture) and increases the firmness of foods
what is a humectant
it retains moisture
list additives that are stabilizers
- carrageenan
- pectin
- cellulose
- gelatin
- vegetable proteins
what is the function of the additive sodium stearate?
anti-caking agent
what is the function of nitrates as an additive?
fixes color, inhibits the spores of clostridium botulinum
what is the function of the additive proprionate?
preservative; mold inhibitor
what is the purpose of the additive ascorbic acid?
enhanced appearance by preventing browning
what are functional foods?
foods that provide more benefits than the basic nutritional benefits
what is meant by convention functional foods?
they are not modified through enrichment, fortification, or enhancement
what are examples of conventional functional foods?
- grape juice and red wine has resveratrol which reduces platelet aggregation
- omega 3 fatty acids in faty fish reduce TG levels
- tomatoes have lycopene which may reduce prostate cancer risk
what is meant by modified functional foods?
they are altered through enrichment, fortification, or enhancement
what are examples of modified functional foods?
- fermented dairy products have probiotics which support GI health
- fortified margarines contain plant sterols and stanol esters which reduce total and LDL cholesterol
- calcium fortified orange juice, iodized salt, folate-enriched breads
what is an example of a medical functional food
PKU formulas free of phenylalanine
what is an example of a functional food for special dietary use
gluten-free, weight loss foods
what are phytochemicals?
biologically active, naturally occurring chemical compounds in plant foods, act as natural defense for the plant
what are some sources of phytochemicals?
fruits, vegetables, legumes, whole grains, nuts, seeds, herbs, spices
what are possible benefits of phytochemicals?
- prevention or treatment of chronic diseases like cancer or heart disease
- may detoxify drugs, toxins, carcinogens, mutagens
- may act as blocking agents, preventing active carcinogen from reaching target tissue-may reduce risk of CHD by protecting LDL cholesterol from oxidation, reducing synthesis or absorption of cholesterol
What are examples of phytochemicals?
- thiols - cruciferous vegetables (sulfur) - detoxification of carcinogens
- soy foods - isoflavones - lower elevated cholesterol
what are some general categories of phytochemicals?
terpenes, carotenoids, lycopene, limonoids, phenols, flavonoids, isoflavones, phytoestrogens, thiols, indols, lignans
what is food synergy?
the additive influence of foods and constituents which, when eaten, have a bneficial effect on health
