Domain 1- Food Science Flashcards
What affects the crispness/texture of fruits and vegetables?
Osmotic pressure within the water filled vacuoles
Water content of vegetable replaced by concentrated salt solution
Diffusion
Used to speed up ripening process of fruits during storage
Ethylene gas
Why should berries and mushrooms be washed JUST before eating?
Because they absorb water and will turn to mush if washed too much in advance
What type of solution prevents enzymatic oxidation (aka browning)?
Acidic solution
Green fruit and vegetable pigments
Acid reaction= chlorophyll –> pheophytin (olive green)
Alkaline reaction= chlorophyll–> chlorophyllin (bright green)
Yellow/Orange fruit and veg pigments
Carotenoids - doesnt change color in acidic or alkaline solutions
Reddish fruit and veg pigments
Lycopene - antioxidant
Red, blue, purple Fruit and veg pigments
Flavonoids – anthocyanins
White fruit and veg pigments
Flavanoids- anxothanthins or flavones
- acid solution –> colorless
- alkaline solution –> yellow
- ex: onions may turn yellow when cooked in aluminum pan
Fruit and vegetables grading
-done by USDA
Grade A: fancy; desserts, salads
Grade B: choice; processed
Grade C: standard; puddings, pies
Fresh produce grading
Fancy Extra #1 #1 Combination #2
10 can = ___ cups?
13 cups, 20-25 servings
What happens to the final product when old potatoes are used in cooking?
It’s sweet, mushy, and cooks a darker brown
-Starch changes to sugar during storage –> higher sugar content causes maillard reaction = browner color
Cooking time for frozen veg is _______ shorter than for fresh veg because _____
- Shorter
- b/c freezing makes them more tender
Blanching
Immersing in boiling then cold water
Preparation for cauliflower
cook for short time covered
Prep for broccoli
microwave –> less time and same flaor
-retains color and vit c better
prep for cabbage
cook for short time, keep lid off initially and cook in large amount of water to prevent strong flavor
Structured part of tendon that surrounds muscle; hydrolyzed to gelatin and becomes tender when heated
Collagen
A protein found in ligaments and cartilage; yellow; resistant to heat and changes little during cooking
Elastin
Amount of fat cover on the carcas is called the _____
Finish
What identifies the cut of a meat?
The shape of the bone
-i.e. round bone = the leg; t-bone= back and ribs
Good source of thiamin (a meat)
Pork
Fish canned with bones
higher calcium content
Main contributor to meat pigment
Myoglobin
myoglobin + O2 –> Red –> oxidation of myglobin –> brown –> further oxidation of myoglobin –> greenish color
Increasing water holding capacity of Meats
INCREASES Tenderness
-i.e. aging meats, acids (vinegar), and salt increased tenderness by increasing water holding capacity of the muscle
Vacuum packaged Meats (“sous vide”)
Anaerobic
Extends shelf life
What does the “USDA Inspected & Passed” symbol mean?
Assures wholesomeness and that animal was healthy at time of slaughter
Meat Grading
indicates quality; based on maturity of animal, marbeling of fat, color, texture
Types of meat grades
Prime (MOST marbeling) –> choice –> Select –> standard (Least marbeling)
What determines the cooking method of meats
the cut of the meat
What should the smoke point be for frying meats?
400 degrees F
Roasting meats SLOWLY results in ____ waste
LESS waste
What happens to collagen when it is cooked and why do “tough” cuts of meat need to cook longer?
Collagen hydrolyzed to gelatin
-“tough” cuts have more collagen and take longer to be softened
Pinkness from nitrites on meats and prevention of botulism
cured meats
Important internal temps:
145 F =
160 F =
165 F =
145= meat and fish 160= ground meats 165= poultry
Dry heat cooking methods for which type of cuts of meat?
Most tender= least used muscles from backbone and loin (*Pork chops come from the loin)
-Roasting
Moist heat method of cooking for which type of cuts of meat?
- Least tender = most used muscles from flank and brisket
- Bottom round cuts should be cooked in water for several hours
When meat is removed from oven and cooking continues to occur and internal temp rises
“Carry over” cooking
Naturally occuring oil in water emulsion; more concentrated portion and more protein by weight
Egg YOLK
Done by “candling” - Grades AA, A, B – thickness of white, location, and condition of yolk
Egg grading
Process Passing an egg in front of a bright light to view its contents and grade the egg
“Candling”
Egg protein coagulates at what temperature?
169-184 degrees F
-can get a custard
When egg is coked at too high a temp or too low a temp for too long –> protein coagulates and liquid is released –> results in tough, watery egg
syneresis
aka “weeping”
Why does adding acid (i.e cream of tartar) stiffen egg white foam?
It tenderizes the protein and allows it to extend more easily
Why do egg whites at room temp whip more quickly and yield a larger volume?
Due to lower surface tension
What causes the surface of the egg to turn green when overcooked?
Ferrous Sulfide –> iron from yolk combines with sulfur from whole egg
Made from dehydrated eggs; the larger the % sag the more the ______ will bend in
custard
Lower in calories and fat and cholesterol; different color and flavor when used in cooking
egg substitute
Eggs lose CO2 when stored in the fridge for too long making them more….?
Alkaline
80% of milk protein, precipitated at 4.6 pH; soft curd
Casein
liquid that drains from curd of clotted milk; milk protein
whey
Milk with 60% water removed; must not have < 7.9% milk fat; caramelization of lactose in canning yields brown color
evaporated milk
concentrated whole milke with glucose or sucrose added
sweetened condensed milk
fermented milk lactic acid bacteria added; increase baking soda when using this type in place of regular milk
cultured buttermilk
What happens to milk when it is heated?
Whey protein precipitates out
butter & margarine % fat ?
80%
Butter (milk fat)
Margarine (vegetable oil or animal fat)
3 Highest fat creams
- heavy cream 2. medium cream 3. whipped cream
Added to processed cheese to prevent fat separation and to add smoothness so it is better for cooking
disodium phosphate emulsifier
Why is disodium phosphate added to quick cooking cereals?
Makes cereal alkaline so particles swell faster and cook quicker
*Avoid on low Na diet
Wheat flours with most to least protein
- Bread flour = MOST protein; hard wheat, strong gluten
- All-purpose Flour: hard & soft wheat
- Pastry flour: soft wheat
- Cake flour: LEAST protein; soft wheat, weak gluten
What type of flour should be used when making pies?
Pastry Flour
If no pastry flour, then cake flour, if no cake flour then all-purpose flour
What does inadequate flour do to a pie crust?
Makes it moist the day after cooking
Alimentary paste –> macaroni product to which eggs have been added
Noodles
When cooking, use amount of water that will be absorbed during cooking to prevent loss of vitamins
Rice
Adding ______ to a flour mixture decreases volume
Bran
-Add more flour and water to provide more gluten and improve the structure
Created by steam, air, or CO2
Leavening
Baking soda + Dry acid + Corn starch
Baking powder
Old baking soda becomes more ______ and causes a loss of thiamin in baked goods
Alkaline
Modifies texture of product by tenderizing -> absorbs some of the water that gluten needs for development
hygroscopic (property of sugar)
Too much sugar results in what type of product?
shiny crust, crumbly, crunchy crust; moist, compact texture; may cause cake to fall in
Leavened with steam, air, chemical leavening agents, NOT yeast; basic ingredients are eggs and flour
Quick breads
What does excess mixing of quick breads result in?
Loss of CO2, overdeveloped gluten, and tunnels
Yellowy colored angel food cake is due to what?
No cream of tartar
Lard and vegetable oil are what % fat?
Butter and margarine are what % fat?
100% and 80%
-When substituting butter for lard, need to use MORE due to decreased fat content
Property of baked goods enhanced by using oil or fat cut into very small pieces
tenderness
Property of baked goods due to leaving fat in larger, course pieces
Flakiness
What types of baked flour mixtures absorb the most fat when fried?
BATTER –> high sugar high fat batters
i.e. pour batter (waffles) and drop batter (muffins)
Final rising of the dough in the pan
Proofing
Amylose (gelling) and amylopectin (non-gelling)
starches
MOST effective and LEAST effective starch thickener
Potato starch = MOST effective
Wheat starch = LEAST effective
Undesireable staling of starch products; gritty texture;occurs in products with a lot of amylose; i.e. separation of gravy
retrogradation
White sauce
Roux: half fat, half flour
-use cornstarch NOT flour as a thickener to get a clear, shiny, sauce
Used to stabilize frozen gravies and prevent separation when thawing
modified starch
The increase in volume when the recipe is agitated during the freezing process; measured by weight
Overrun
Making a frozen dessert with whipping cream instead of 1/2 and 1/2 will result in a ______ product
Smoother
Immitation ice cream; butterfat replaced by hydrogenated vegetable oil
Mellorine
Incomplete protein low in methionine, lysine, and has NO tryptophan; changes a liquid into a solid
Gelatin
An enzyme in fresh/frozen pineapple that breaks down protein and prevents gelation
Bromelin
Food additive that Prevents oil and water from separating; monoglycerides, diglycerides, lecithin, disodium phosphate
emulsifiers
Food additive that Acts as a humectant –> retains water and increases firmness of foods
glycerol monostearate
food additive that Inhibits spores of clostridium botulinum
Nitrites
Food additive that inhibits mold
proprionate
Food additive that enhances appearance by preventing browning
Ascorbic acid
A functional food that has plant sterol and stanol esters that reduce total and LDL cholesterol
Fortified margarine
A functional food that has reservatrol which can decrease platelet aggregation
Grape juice and red wine
A functional food that is found in fatty fish and lowers TG levels
Omega-3 Fatty acids
A functional food that contains probiotics that support GI health
fermented dairy products
A functional food that contains lycopene and can decrease the risk of prostate cancer
Tomatoes
Example of a phytochemical
Cruciferous vegetables –> contain thiols and sulfur which are involved in the detoxification of carcinogens
CHO in order of decreasing sweetness
Fructose –> sucrose –> glucose –> sorbitol
