Food Science Flashcards
When should berries and mushrooms be washed?
Just before serving
What accelerates ripening of fruits during storage?
Ethylene gas
What is the green pigment in fruits/vegetables?
Chlorophyll
Chlorophyll turns to _ when in an acid.
Pheophytin
Chlorophyll turns to _ when in an alkaline solution.
Chorophyllin
Yellow and orange pigments are also known as _.
Carotenoids
What is the effect of carotenoids in an acid/alkaline solution?
Little effect.
What are lycopenes?
Pigments responsible for the red colors in fruits such as tomatoes, watermelon, apricots.
What is the function of lycopenes?
Antioxidants/phytochemicals.
What happens to onions when they are cooked in an aluminum pan?
They turn yellow.
Describe the grading of canned fruits and vegetables.
Grade A - desserts/salads (fancy)
Grade B - processed (choice)
Grade C - puddings/pies (standard)
Describe the grading of fresh produce.
Fancy, Extra #1, #1, Combination, #2
Who grades fruits and vegetables?
USDA
Describe the cooking time for frozen vegetables.
Shorter cooking time than fresh because blanching and freezing have made them tender.
Describe the cooking process of cabbage.
cook for a short period of time in a large quantity of water of with the lid off to let acids escape/minimize strong flavor
How many cups are in a #10 can?
13 cups (20-25 servings)
What is the structural part of tendons that surrounds the muscle?
Collagen
What happens to collagen when it is in heat?
It is hydrolyzed to gelatin and becomes tender.
What is the component of meat found in ligaments/cartilage that is resistant to heat?
Elastin
Pork is a good source of _.
Thiamin
Canning fish with bones, oysters, or shrimp raises the content of what mineral?
Calcium
What causes the green color of meat?
Further myoglobin breakdown/oxidation
How does vacuum packing increase the storage life of meat?
It is anaerobic so bacteria cannot grow
Describe USDA inspection and grading of meat.
Inspection/grading is mandatory at slaughter and says that the meat is fit for human consumption.
List the grades of meats in order from best to worst.
Prime, choice, select, standard.
What is meat grading based on?
Maturity of the animal, marbling of fat, color, and texture
What determines the method of cooking meat?
The cut of the meat
What is the safe minimum internal temperatures for pork, beef, veal, lamb, steaks, roast, and fish.
145 F
What is the safe minimum internal temperature for cooking ground beef, ground veal, or ground lamb?
160 F
What is the safe minimum internal cooking temperature for turkey, chicken, and duck?
165 F
What is the effect of adding nitrites to meats?
Inhibits botulism (turns meat pink).
After roasting, what is carry over cooking?
When meat is removed from the oven, internal meat temperatures rise 15-25 F and continues to cook the meat for ~10 minutes.
Describe braising.
A moist-heat cooking method. Flour meat, brown, cover, and simmer in liquid.
Describe acceptable fresh fish.
Bright red gills, bright shiny skin, firm when touched.
Describe the nutrient contents of egg yolk compared to egg whites.
More concentrated than white, more protein, fats, minerals, and vitamins.
How are eggs graded?
By candling - passing an egg in front of bright light to view contents.
List the grading of eggs.
AA, A, B
What temperature coagulates protein and sets custard?
62-70 C
What helps to stiffen an egg white foam and how?
An acid - it tenderizes the protein and allows it to extend more easily.
Why do egg whites at room temperature whip better?
Lower surface tension.
What might happen when you make a custard with dehydrated eggs?
The custard may be grayer, less yellow, have an eggy flavor, and be watery
What differences may be seen when cooking with egg substitutes?
Color and flavor differences
What is cultured buttermilk?
Skimmed/partly skimmed milk with added lactic acid.
When using buttermilk in place of regular milk, what needs to also be changed?
Increase the baking soda.
What is sweet acidophilus milk and how does it effect lactose?
Skim milk plus acidophilus bacteria - reduces lactose.
What happens to whey protein when milk is heated?
Whey protein is precipitated out on bottom of pan or surface of milk.
What does adding an acid to milk do?
Precipitate casein.
What causes butter to turn rancid?
Taking up oxygen and releasing hydrogen.
What are the components of butter vs margarine?
Butter is 80% milk fat, margarine is 80% vegetable oil or animal fat.
List the creams with the most fat.
Heavy/thick cream, medium, whipped cream
What is the purpose of adding disodium phosphate to cheese?
It emulsified the cheese so that the fat does not seperate out during cooking.
What is the purpose of adding disodium phosphate to quick-cooking cereals?
Makes the cereal alkaline so the particles swell faster.
What is the ratio of rice to water when cooking rice?
1:2
Which type of flour has the most protein?
Bread flour
Which type of flour has the least protein?
Cake flour.
What needs to be compensated when adding bran to a product?
Increase flour and liquid because bran is heavy and decreases volume of end product.
What happens as baking powder ages?
It becomes more alkaline causing loss of thiamin in baked goods
What does it mean when someone says sugar is hygroscopic?
Sugar modifies texture by tenderizing (it absorbs water)
Describe leavening with quick breads.
Leavened with stem, air, chemical leavening agents; basic ingredients are egg and flour.
What happens when you mix a quick bread excessively?
Carbon dioxide is lost, gluten is overdeveloped, there are tunnels from top to bottom, and you have a tough/heavy product.
What is a rich cake?
Increased fat, sugar, egg
What causes yellowing in cakes?
An alkaline batter (excess soda)
What causes a fallen center in cakes?
Excess sugar, excess dat, excess baking powder, inadequate mixing, oven temperature too low, open door during early baking.
What causes a tough, dry crumb in cakes?
too much flour or egg, too much mixing, too little fat of sugar, overbaking
What causes course texture in cakes?
Too much baking powder or sugar, oven temperature too low, inadequate mixing.
What causes poor volume in cakes?
Too little baking powder, improper level of sugar or fat.
What are the main components of pastry?
Flour, fat, liquid, and salt.
What do you need to do when substituting butter for lard?
Use more - butter is only 80% fat
What increases tenderness in pie crusts?
Using oil, soft fats, or fat cut into very small pieces
What increases flakiness in pastries?
Leaving fat in coarse particles
What is the sponge method of making dough?
Combining liquid with yeast and part of flour and allow this batter to ferment for several hours - add sugar, salt, fat, and rest of flour - knead
What happens to proofing time when you do the sponge method and what needs to be changed in the recipe?
Shortened, use a stronger flour that is higher in protein
What happens to process time when using the continuous bread-making method?
Reduces process time
Which starch is the most effective at thickening? the least?
Potato - most, wheat - least
What is a roux?
Half fat, half flour
When making ice cream, what is overrun and the %?
The increase in volume from freezing and whipping, should be 70-80%
How can you produce smoother ice cream?
Increase fat
What is bromelin?
An enzyme in fresh or frozen pineapple that breaks down protein and prevents gelation
What is the best temperature to brew coffee?
185-203 F
Name some additives that act as an emulsifier.
Monoglycerides, diglycerides, lecithin, disodium phosphate
What does the additive glycerol monostearate do?
Humectant (retains water to increase firmness
What do nitrites do?
Fixes color, inhibits spores of clostridium botulism
What does proprionate do?
Acts as a preservative, inhibits mold
What does ascorbic acid do as a food additive?
Enhances appearance by preventing browning
What are functional foods?
Provide more benefit than the basic nutritional benefits
Name the functional food effect of fortified margarines
Contain sterols and stanol esters that reduct LDL and total cholesterol
Name the functional food effect of grape juice and red wine
contain resveratrol which reduces platelet aggregation
Name the functional food effect of fatty fish
contain omega-3s that reduce TG levels
Name the functional food effect of fermented dairy products
contain probiotics that support GI health
Name the functional food effect of tomatoes
Contain lycopene which may reduce prostate cancer risk
What is food synergy?
the additive influence of foods and constituents which have a beneficial effect on health
