Food Science and Nutrition Composition Flashcards
Rd exam
What vitamins are found in F/V?
Vitamin A, B, C
Crispness of Vegetables (state of turgor) is due to what?
osmatic pressure of water-filled vacuoles
As F/V age, what increases?
hemicellulose and lignin
What is the limiting PRO in soybean?
methionine
What is the PRO concentrates in soybean?
> 70% PRO; >90% PRO isolates
Soybeans are used in what?
Textured Protein Products (TVP)
What accelerates the ripening process of fruit during storage?
Ethylene Gas
What is the fruit ripening process?
Protopectic–> pectin (ripen fruit) –> pectiv acid (overripened fruit)
Which F/V best ripen at room temperature?
Avocadoes, Bananas, Tomatoes, Pears
When an apple is stored in a controlled atmosphere (reduced oxygen), will the apple aging be increased or delayed?
Delayed
What F/V should be washed just before serving?
Berries and Mushrooms
Fruit with low vitamin C darken when cut because of what?
Enzymatic Actions
Prevented by acids
How do you prevent fruit from darken when cut?
- dipping the fruit in citrus juice
- adding sugar before freezing
- Heat to boil
What happens when F/V are cooked?
softens cellulose
cooks starch
What is the green pigment of F/V called? Is it soluble or insoluble in water?
Chlorophyll
insoluble in water
When green pigment is cooked in an acid (vinegar), this is called what? What color will appear?
Phenphytin
Olive Green
When green pigment is cooked in an alkaline (baking soda), what is this called? What color appears? What happens to the food item?
Chlorophyllin
Bright green
mushy, hemicellulose broken down
What is yellow/orange pigment color called?
Carotenoids
Are Carotenoids soluble or insoluble in water?
Insoluble in water
What happens when acid is added to a Carotenoids?What happens when alkaline is added?
Has little to no affect for both acid and alkaline
What is lyopenes?
Red pigment found in tomatoes and watermelons
Antioxidant
What are Flavinoids?
Are the soluble or insoluble in water?
Anthocyanins- red, blue, purple
Anthoxanthins or Flavones- white
Soluble in water
Anthocyanins when acid is added, what happened?
turns bright red
Anthocyanins when alkaline is added, what happened?
turns blue
Anthoxanthins or Flavones when acid is added
Anthoxanthins or Flavones when akaline is added
colorless turns yellow (onion cooked in almunmin pan)
What is glutaminic acid found in? What form is it used in?
Young vegetables
Used in forms of MSG salt
Sulfur is found in what vegetables?
cabbage and onions
What is the tip when cooking bussel sprouts?
best flavor, cook uncovered with little waste.
The flavor of fruit is due to?
acid, sugar, aromatic compounds
What is tannis?
Unripen fruit (banana), unpleasant taste
What is Grade A of F/V
What is Grade B of F/V
What is Grade C of F/V
A- desserts, salads (fancy)
B- processed (choice)
C- pudding, pies (standard)
How do potatoes get green color in skin?
Due to Chlorophyll because the potato is exposed to light during storage
What happens with old potatoes?
what natural toxicant can be included?
They are sweeter when cooked, darker in color due to Mallard Reaction, and have a softer texture (mushy)
Solarine
What are F/V graded by?
USDA
Cooking F/V: Boil
small amount of water with salt
cook with lid less not told to
Cooking F/V: Stream
perforated container, cooked over boiling water
Cooking F/V: Stir Fy
use tender vegetables, high in moisture, dont drain
Cooking F/V: Frozen
short time cooking because of blanching (soaking in boiling water)
Freezing makes vegetables tender
10 can
6/case; 13 cups; 6 lbs, 3 oz, serves 20-25 ppl
What is chalazae?
what anchors the yolk in an egg; holds yolk in center of egg
What vitamins are found in egg?
Vitamin A, D, and Riboflavin
With yolk, the more concentrated in white
The more PRO by weight
Grading of eggs are determined by?
candling- holding a bright light to the egg to see the content of the egg. placement of the white and yolk
How long can Grade A eggs be stored in the refrigerator to maintain freshness?
up to 6 months
How will a fresh egg appear in cold water? How does shell look?
Sinks to the bottom of cold water, has dull, tough shell
When an egg in coagulates,
it sets a custard
What is synersis (weeping)?
when liquid is released from a coagulated product.
This occurs when egg is cooked at a too high temp, too low temp, cooked for too long and forms a tough, watery product
Leavening: What happens when an acid is added to an egg?
acid stiffens the egg white form by tenderizing the PRO and allowing it to extend easily
What do egg whites do at room temp.?
They whip more quickly and yield a large volume due to lower surface tension.
What does sugar do to egg form?
It stabilizes the form.
What is emulisifcation?
When PRO in the egg forms a thin film around droplets of oil
Emulsifying: What is yolk?
A naturally occurring oil in water emulsion.
Why does egg yolk yield a stiffer, more stable emulsion than egg whites?
Because egg yolks have more PRO
What does lecithin help yolk to do?
It helps yolk act as an emulsifier
Lipoproteins stabilize emuluization by?
interacting at the surface of the oil droplets to form a layer.
Mayonnaise is a food emulzier because?
it is stabilized by egg yolk
Water preparation of an egg is what?
Poaching and Coddling.
What does salt and vinegar do to an egg?
improves the shape by hastening (speeding up) coagulation.
Surface of an egg turns green when?
The egg is overcooked, when the yolk cools too slowly. and this is due to ferrous sulfide
What is ferrous sulfide?
combination of iron from yolk and sulfur from whole egg
How can an egg be cooked?
Dry Heat, Custard, Water preparation
Dry Heat: What happens when the egg is undercooked and overcooked?
Overcooked- egg is tough
Undercooked- excessive shrinkage when removed from the oven
Custard: When there is a large % sag
more tender the gel will be.
When a custard is overcooked?
custard will not sag, will crack open with pressure
Egg Substitutes
Lower in calories, fat, and cholesterol
Higher in sodium
What happens when egg substitutes are used in cooking?
The flavor and color of the food items will be different
When eggs are stored in the refrigerator for too long, what happens?
appearance and usage deteriorates lose of carbon dioxide, egg becomes from alkanoic lose water white becomes watery yolk flattens odors can be absorbed
What structural parts make up meat?
collagen and elastin
what is collagen
structural part of the tendon that surrounds the muscle.
What happens when collagen is heated?
hydrolyzed to gelatin, becomes tender (soft)
What is elastin? what happens when heat is added?
Found in ligament, cartilage
resistant to heat, no change when cooked
Yellow color
What is finish?
amount of fat around the carcass
What determines the cut of the meat?
Shape of the bone
Protein content in meat?
16-23%
What vitamins and minerals are found in meat?
thiamin, niacin, riboflavin, iron, cooper, trace mineral
Pork is a good source of what?
thiamin
What is the difference between fish and meat?
Fish: lower calories, more moisture, less fat, high PRO
What fish are high in Ca+
Fish with bones, oysters, shrimp
What happens when TVP is added to ground meat?
yields more servings, lower cost
What is myoglobin?
contributor or meat color
What is the myoglobin process
myoglobin + oxygen = red-brown-green
green- further myoglobin reaction
When meat ages,
tenderness is increased
Change in PRO due to enzymes that increase water-holding capability
what does acid and salt do to meat?
increase tenderness by increasing the water-holding capability
What is sous vide? What is it used for?
vacuum-packed meat
anaerobic
extends storage life of meat
What is MAP
Modified Atmosphere Packing
air is removed and replaced by carbon dioxide or nitrogen
Is inspection of meat mandantory?
yes
Who grades meat? When is this done?
USDA, at slaughtering
What is the Wholesome Meat Act
Act that assures consumers that meat was healthy when slaughter and meat is fine for human consumption
What are grades of meat?
Prime, Choice, Select, Standard (PCSS)
Prime cuts have what?
more marbling
Standard cuts have what?
less marbling
How is the cooking method determined for meat?
By the cut of the meat
Most tender meat
Medium tender
Less tender meat
less muscles used (lion, backbone)
meat is at the shoulder (chuck)
more muscles used (flank, brisket)
What temperature do you roast meat?
325 F
When meat is cooked at high temperatures, what happens?
meat shrinks, meat is tougher
slow cooked roast does what
yield less waste
When do you insert a thermometer in meat?
Before cooking
What temperature should ground beef, ground veal, ground lamb be cooked at?
160 F
What temperature should beef, pork, veal, lamb, roast, fish be cooked at?
145 F
What temperature should chicken, turkey, poultry be cooked at?
165 F
What happens when meat is cooked?
Protein is coagulated
Collagen is hydrolyzed to gelatin (softens up)
Tough meats need to be cooked well done because?
They have more collagen which needs more time to be soften up
Why does meat surface turn brown? What is the process of internal color change or meat?
Due to pigment breakdown
Heat changes internal color for red-pink-brown-gray
Cured meat is pink due to
nitrates
this prevents bolisium
What are cooking methods for meat:
Dry Heat and Moist Heat
What are examples of dry heat?
Frying, Broiling, Roasting
What are examples of moist heat?
braising, simmer, steam, stewing
Frying
> 400 F, high smoke point is desired property of fat
How does carry-over cooking occur when roasting meat?
When meat is removed from the oven, carry-over cooking occurs and the internal temperature of the meat increases (15-25 F)
When do you use dry heat?
For tender cuts of meat
When do you use moist heat?
For less tender cuts or meat, more tough meats meats with more connective tissues
What does proteolytic enzyme do? What is an example?
Tenderizes meat
Ex: Papaya and Salt
Fish can be cooked using
dry heat or moist heat
Fresh fish should look like what?
bright red gills, bright shiny skin
What PRO are milk made up of?
Casin and Whey
What is Casin?
What is Whey?
Casin- 80% of milk, precipitates with an acid, forms soft curb
Whey- liquid that drains form curd of clotted milk
How is cultured buttermilk made up of?
Skim milk or part skim milk + lactic acid
When you are using buttermilk instead of regular milk in a recipe, what should you do?
increase baking soda
Sweet acidophilus milk has what?
less lactose (make up of skim milk + acidophilus bacteria)
What happens when you cook milk?
Whey PRO precipates out of the bottom of the pan or surface of milk
Acid precipitates what?
casin in milk
Butter is made up of?
Margarine is made up of?
Butter- 80% milk fat
Margarine- 80% animal fat or vegetable oil
When butter is overcooked, what happens?
It becomes rancid, takes up oxygen and releases oxygen
Creams with the most fat include:
Heavy or thick- > 36%
Medium 30-36%
Whipping Cream- 35%
Cheese is made of ?
warm milk + lactic acid bacteria
When rennet is added to cheese,
Casein coagulates, forms curd
separate curd from the whey (liquid)
Why is processed cheese better to cook with?
because it has an emulsifier added (called disodium phosphate)
How do you want to cook cheese products?
short amount of time at a moderate temperature
Quick-cooking cereal contains what?
disodium phosphate, makes cereal alkaline which allows the particles to swell and cook faster
What two food items have disodium phoshate added?
Processed Cheese and Quick Cereals
What is graham/whole wheat flour?
entire grain
Bread flour content
strong gluten
more PRO of flour (11.8%)
All-purpose flour content
blend of soft and hard wheat, less gluten
Cake flour content
least and weaken gluten
less PRO in flour (7.5%)
What is the difference between bread flour and cake flour?
Bread flour has MORE PRO in flour, LESS starch
Cake flour has LESS PRO in flour, MORE starch
What is flour enriched with?
Thiamin, Niacin, Riboflavin, Iron, Folic Acid
What does self-raising flour consist of?
salt, flour, baking power
Why is durum wheat used to make pasta?
high in gluten, which allows the product to be flexible after cooking
What are the cookery rules when cooking rice?
used the amount of water that will be absorbed during cooking
vitamins are lost when you cook rice in large amounts of water or when the water is drained out
What are the main factors of baking?
Flour, liquid, leavening agent, salt, egg, fat, sugar
What are the properties of flour when baking?
gluten from flour gives elastic properties to baking goods.
made from gliadin and glutenin through the process of hydration and mixing
How is flour strength determined by?
capability to retain leavening which depends on the gluten quality
Bread flour is strong b/c more PRO
Cake flour is weak b/c less PRO
What happens when bran is added to flour? How do you compensate?
Bran + Flour= decrease the volume of the product
increase liquid and flour to compensate
What does liquid do when baking?
it hydrates gluten
starts the action of chemical leavening agents
dissolves salt and water
gelatinizes starch
What are the properties of leavening agents when baking?
to create steam, air, and carbon dioxide
Baking Powder is a mixture of what?
baking soda + dry acid + cornstarch
What happens when baking power becomes old?
becomes more alkaline, causes baked good to loss thiamin
What does salt do in baking
adds flavor, keeps yeast from sticking
What does an egg do in baking
stabilizes product
retains leavening agent
distributes shorten by emulsification
adds flavor and color
What does fat do in baking
coagulating gluten particles
adds tenderness
What does sugar do in baking
tenderizes product (hygroscopic) soften gluten and prevents gluten development by absorbing the water that gluten would need for development
What happens when you use too much sugar when baking
coarse cells, thick walls, shiny crust, crumbly product
The basic ingredients of quick bread are:
egg and flour
When you overmix a batter, what happens?
loss carbon dioxide
overdevelopment of gluten
tunneling from the top to bottom
tough, heavy product
Rich cake consist of
increase egg, fat, sugar
Too much sugar in cake
more time needed to cook so gluten is coagulated
volume of the cake increases
gluten become weaken and snaps
cake falls in the center
Cake: what happens when you have a yellow cake as an end result
caused by alkinane batter (too much baking soda added)
When a cake falls, what is this caused by?
too much sugar, fat, baking soda,
over temperature too low
inadequate mixing
Pasty consist of what 4 ingredients
liquid, fat, salt, flour
When substituting butter for lard, what should you do?
use more butter
lard= 100% fat butter= 80% fat
How do you achieve a tender crust?
using oils, soft fats, or fat cuts that are cut into small pieces
Flaky crust is achieved by?
the fat in coarse particles
fat melts
forms a hole when steam collects and pushes upward against surface
Yeast Dough: continuous bread making method
used in commercial baking
Yeast Dough: straight dough method
used to make bread
What is proofing time?
final rising of the dough
use strong flour, high PRO (bread flour) for sponge method
What to do when baking in high altitudes
decrease amount of baking power, increase amount of liquid
Starch is made up of:
amylose and amylopectin molecules
Starch: amylose does what
responsible for gelatin in cooked, cooled pastes
What are thickening agents
potato (high)- waxy corn-waxy rice-waxy sorghum-tapioca, wheat
Pastry and Cake Flour will thicken more when thickening agent is added because
they contain more starch, less gluten
Gelatinization
swelling that occurs when starch is heated in water close to the boiling point
What has sugar and water do during gelatinization?
they compete with one another
