Domain I: Principles of Dietetics: Food Science Flashcards
Fruits and vegetables are made up of ___-___% water, along with both digestible and indigestible carbohydrates, vitamins, and minerals
75-93%
Fruits and vegetables have crispness, or ____, which is due to the osmotic pressure of water-filled vacuoles
Turgor
During ripening, fruits and vegetables undergo chemical changes due to ____ which cause starch to change to sugar
Enzymes
During the ripening process, protopectin is coverted to ____ (ripe fruit) and then to ____ ____ (overripe fruit)
Pectin; pectic acid
____ gas accelerates ripening of fruits during storage
Ethylene
Aging is delayed in apples stores in controlled atmosphere, or reduced _____
Oxygen
The green pigment in fruits and vegetables is ____
Chlorophyll
Chlorophyll is _____ in water
Insoluble
Chlorophyll changes to an ____ green color when exposed to acid
Olive
The olive green color of vegetables that are exposed to acid is due to _____
Pheophytin
Chlorophyll changes to a ____ green color when exposed to alkaline substances
Bright
Texture of vegetables exposed to alkaline substance:
Mushy (due to hemicellulose breakdown)
The yellow/orange pigments in fruits and vegetables are ____
Carotenoids
Of all the pigments, carotenoids are least effected by changes in ____
pH
Carotenoids are ____ in water
Insoluble
Carotenoids are minimally effected by ____ and ____ substances
Acid, alkaline
One type of carotenoid are ____, which are antioxidants and phytochemicals
Lycopenes
What are examples of flavonoid pigments?
Anthocyanins, anthoxanthins. flavones
The pigments that provides red, blue, and purple color to fruits and vegetables are _____
Anthocyanins
Anthocyanins are ____ in water
Soluble
Anthocyanins are greatly impacted by ____
pH
Anthocyanins turn ____ in acid
Red
Anthocyanins turn ____ in alkaline substances
Purple
The types of flavonoid that are colorless, white, or yellow are ____ and ____
Anthoxanthins, flavones
Anthoxanthins and flavones are ____ in water
Soluble
Anthoxanthins and flavones become _____ in acid due to the bleaching effect
Colorless
Anthoxanthins and flavones become ____ in alkaline substances or when cooked in an aluminum pan because flavones chelate aluminum
Yellow
Berries and mushrooms should be ____ just before serving
Washed
Fruits low in vitamin ____ darken/oxidize rapidly when cut due to enzymatic action
C
To prevent oxidation, you can…
-Dip in citrus juice
-Add sugar before freezing
-Heat to boiling
One dozen oranges will produce ____ cups of juice
4 (1 qt)
Cooking vegetables and fruits softens ____, as well as increases keeping quality and cooks starch
Cellulose
When sweetener is added to liquid of packing juice, the density of the syrup is expressed as a percentage by weight of _____
Sucrose
Percent weight of sucrose is measures with a ___ hydrometer
Brix
____ is a thin puree of fruit or vegetable, sugar, and water used as a sauce
Coulix
A ____ is a fruit cooked/stewed in syrup
Compote
Potatoes have ____ compounds that cause color changes in raw, peeled, or bruised potatoes
Phenolic
A green color under the skin of potatoes is due to chlorophyll that develops when the potato is exposed to light during storage; this may be accompanied by ____, a natural toxicant
Solanine
Starch changes to ____ during storage of fruits and vegetables which causes changes in taste, color, and texture
Sugar
Old potatoes taste ____, cook to a darker brown (Maillard reaction) and are softer in texture
Sweeter
Acidic vegetables that need more time to boil require more ____ and should be cooked without a lid
Water
____ cooking retains the color and flavor of vegetables (need to cut small)
Pressure
Frozen vegetables have a ____ cook time due to blanching and freezing that have made them more tender
Shorter
To minimize development of a strong odor when cooking cabbage, cook for a short time, keep lid off initially to let ____ escape, and cook in large amounts of water
Acid
____ acid is found in young vegetables and is used in a form of salt (MSG)
Glutamic
_____ gives an odor to onions and cabbage
Sulfer
____ cause an astringent feeling in the mouth (unripe bananas)
Tannins
USDA grades of fruits and vegetables are based on…
-Quality
-Firmness
-Color
-Maturity
-Freedom from defects
-Uniform size and shape
Grades for canned fruits and vegetables:
-Grade A/Fancy (desserts, salads)
-Grade B/Choice (processed)
-Grade C/Standard (puddings, pies)
Grades for fresh produce:
-Fancy
-Extra #1
-#1
-Combination
-#2
Muscle of meat products is composed on bundles of fibers called _____ which are held together by different types of connective tissue
Myofibrils
____ is a structural part of the tendon that surrounds muscle
Collagen
In heat, collagen is hydrolyzed to ____ and becomes tender
Gelatin
Elastin is another type of connective tissue; it is ____ to heat so it changes very litter with cooking
Resistant
Elastin is found in _____ and ____ and has a yellow color
Ligaments and cartilage
The ____ describes the amount of fat cover on a carcass
Finish
Meat, fish, poultry, and meat alternatives are usually between ___-___% protein
16-23
Meat contains carbohydrates in the form of ____ in the liver and ____ in the blood
Glycogen, glucose
What vitamins and minerals exist in meat?
-Thiamin
-Niacin
-Riboflavin
-Iron
-Copper
-Trace minerals
Pork is an especially good source of ____
Thiamin
____ content is high in fish canned with bones, oysters, and shrimp
Calcium
The main contributor to meat color is _____
Myoglobin
Myoglobin, when exposed to oxygen, changes to what colors?
Red, brown, green
When myoglobin turns green, it is due to further myoglobin _____
Breakdown
Aging meat increases ____ due to a change in muscle protein brought about my enzymes which increase the water-holding capacity of the muscle
Tenderness
Vacuum-packing meat in an oxygen-impermeable filmed, stored unfrozen at 0 degrees C (32 degrees F) is ____ ____ ___, which extends the storage life of meat
Anaerobic sous vide
____ _____ packaging prolongs shelf life by removing oxygen and replacing it with carbon dioxide and nitrogen
Modified atmospheric
Modified atmospheric packaging prevents deterioration by slowing _____
Respiration
____ is mandatory for meat products, while grading is voluntary
Inspection
The ____ ____ Act of 1967 assures consumers that that the animal was healthy at the time of slaughter and the meat is fit for human consumption (indicated with a purple stamp that says “USDA inspected and passed”)
Wholesome Meat
Grading indicates _____ of meat; the grade appears on a sheild
Quality
Meat is federally graded by the ____ ____ ____ of the USDA
Agricultural Marketing Service
Grades for meat (determined at slaughter):
-Prime (most marbling)
-Choice
-Select
-Standard (least marbling)
Grading of meat is based on…
-Maturity of animal
-Marbling of fat
-Color
-Texture
Meat ____ refers to a numbering system for ordering wholesale cuts (IMPS, NAMP)
Specifications
When roasting meat, cook at a temperature of ____ degrees as high temperatures increase shrinkage and toughen meat (low temperatures yields less waste)
325
Safe minimum internal temperature for pork, beef, veal, lamb, steaks, roast, and fish:
145 degrees
Safe minimum internal temperature for ground beef, ground veal, ground lamb, etc:
160 degrees
Safe minimum internal temperature for turkey, chicken, and duck:
165 degrees
Physical and chemical changes to meat as it cooks:
-Protein coagulates
-Collagen is hydrolyzed to gelatin and softens
-Surface browns due to breakdown of pigments
-Heat changes interior from red to pink to brown to grey
Color of meat changes during cooking because heat denatures ____, and then iron is oxidized
Globin
Cured meats are pink from nitrites, which inhibit _____
Botulism
For jerky, heat meat to ____ degrees before dehydration, and heat poultry to ____ before dehydration
160; 165
Use ____ heat methods (such as frying, broiling, roasting, or grilling) to cook tender cuts of meat near the backbone such as the loin or sirloin
Dry
A desirable property of fat used in frying is a high smoke point, typically above ____ degrees
400
Fats, in order from highest smoke point to lowest:
-Safflower (513)
-Soybean
-Canola
-Corn
-Palm
-Peanut
-Sunflower
-Sesame
-Olive (375)
-Lard (375)
-Shortening (365-370)
-Butter (350)
Monoglycerides (shortening) have ____ smoke points
Low
It is best not to fry ____ cuts of meats like bottom round
Tougher
____ involves the uptake of oxygen in an unsaturated fatty acid
Rancidity
The healthiest plant oils are all highly _____, meaning they are susceptible to rancidity
Unsaturated
Olive oil has more _____ fatty acids, which makes it less susceptible to rancidity than soybean oil which has more _____ fatty acids
Monounsaturated; polyunsaturated
Broiling is a form of ____ heat
Radiated
When meat is removed from the oven, “carry-over cooking” will occur for about ten minutes; internal temperature will rise ___-___ degrees F
15-25
For best results, allow roast to stand ____ minutes before carving
30
____ heat cooking methods are best suited for less tender cuts of meat with more connective tissue (bottom round, chuck, brisket)
Moist
____ is a moist heat cooking method that involves added flour to the meat, browning, a simmering in liquids in an over or range-top
Braising
____ is a moist cooking method that requires heating in water 170-185 degrees with the appearance of bubbles
Simmering
____ is a moist cooking method that requires heating over, not in, water
Steaming
____ is a moist cooking method that requires adding water or other liquids during cooking
Stewing
A proteolytic enzyme called ____ tenderizes meat (made from a blend of papaya and salt)
Papain
In soybeans, _____ is the limiting amino acid, meaning that it limits the rate of protein synthesis
Methionine
In soybean protein concentrate, there is over ____% protein; in soy protein isolates, there is over ____%
70; 90
Soybeans are used to make ____ ____ products; this can be mixed with ground meats to extend the number of servings while lowering costs, and also can add juiciness due to its water content
Textured protein
Forms of soy:
-Edamame (soybean pod)
-Tofu (coagulated soy protein)
-Miso (soy paste)
-Tempeh (aged soybean and grain)
-Natto (fermented soybean)
Since fish is more perishable than meat, store at a ____ temperature
Lower
Fresh fish with head attached should have bright ____ gills and bright, shiny skin (if gills are grey and dull, reject it)
Red
_____ toxicity is linked to inadequate refrigeration of tuna, mackerel, and mahi-mahi
Histamine
Eggs have a porous shell that allows for the exchange of moisture and gas; it is covered in ____ that prevents excessive loss and protects the contents
Bloom
The color of the shell is unrelated to food ____ or ____
Value or quality
The inner membrane of the egg contracts, leaving air space in the large end; this air space becomes ____ over time
Larger
An indicator of a good-quality egg is a high proportion of ____ ____
Thick white
Yolk is surrounded by _____ membrane
Vitelline
____ are what anchors the yolk to the white
Chalazae
Egg yolk is a naturally occurring ____ in an emulsion with water
Oil
Nutritive value of an egg:
-80 kcal
-6 g protein
-5 g fat
-Vitamin A, D, riboflavin
The yolk is more ____ than the white and has more protein (by weight), fat, minerals, and vitamins (% composition of protein: egg white 11%; egg yolk 17.5%)
Concentrated
The color of the egg yolk depends on the amount and type of ____ in the hen’s diet
Pigment
What are the three possible grades of an egg?
-AA
-A
-B
_____ is a technique of grading eggs that judges the thickness of white, and the location and condition of the yolk
Candling
Grading of an egg does not include the _____ of the shell nor the ____ of the egg
Color; size
Size of an egg is based on weight per ____
Dozen
Raw eggs can be stored in the fridge at ___-___ degrees for 3-5 weeks
40-45
Grade A eggs can be maintained for ____ months in cold storage (29-32 degrees)
6
Old eggs will ____ due to increased air space
Float
Egg protein coagulates at ___-___ degrees and sets as a custard
62-70
Coagulated egg protein is used to…
-Bind
-Give firmness
-Give stability
-Coat food
-Add brownness
-Clarify liquids
____, or weeping, is the process of liquids being released from a coagulated product
Syneresis
Syneresis occurs when eggs are…
-Cooked at too high a temperature
-Cooked at too low a temperature for too long of a time
Syneresis creates a ____, watery product
Tough
The ____ property of eggs depends on the amount of air beaten in and retained; it happens when an egg foam is heated, air expands, egg whites stretch, and protein coagulates
Leavening
An _____ stiffens an egg white foam by tenderizing the protein and allowing it to extend more easily
Acid
Egg white foams are compared by measuring ____ ____, which measures the relative density of a substance in relation to that of water
Relative gravity
Specific gravity is calculated by dividing the weight of a given volume by the weight of the same volume in ___
Water
Egg white at room temperature whip more quickly and yield a larger volume due to ____ surface tension
Lower
Sugar can also ___ egg white foam
Stabilize
The protein in an egg forms a thin film around droplets of oil which stabilizes _____
Emulsions
Egg yolk yields a stiffer, more ____ emulsion than egg white because it has more protein by weight
Stable
_____ helps yolk act as an emulsifier
Lecithin
_____ stabilize the emulsion by interacting at the surface of the oil droplets to form a layer
Lipoproteins
____ is a food emulsion stabilized by egg yolk
Mayonnaise
When poaching or coddling an egg, use a ____ quality egg as appearance in important
High
___ and ___ improves shape of eggs cooked in water by hastening coagulation
Vinegar and salt
Surfaces of yolk turn green when overcooked or allowed to cool slowly due to the combination of iron from the yolk and sulfur from the whole eggs which creates ____ _____
Ferrous sulfide
When cooking eggs with ____ heat, overcooking toughens the egg
Dry
When cooking eggs with dry heat, undercooking results in excessive ____ when removed from the oven
Shrinkage
In custards, the greater the percent ____, the more tender the gel (objective measure of the quality of a custard)
Sag
Custards made from ____ eggs may be grayer and less yellow, have an eggy flavor, and be watery
Dehydrated
Eggs can be ____ as long as the shell is removed first (can be whole or in parts)
Frozen
10% ___ or ____ (by weight of yolks) is added to frozen eggs as a stabilizer
Salt or sugar
Eggs can be dried by being vacuum packed in ____ gas
Nitrogen
Dried, fortified eggs are ____% white, and ____% yolk
70, 30
Baker’s special eggs have added ____ for added foaming ability
Sucrose
Egg substitutes tend to be higher in ____
Sodium
Deterioration of egg substitutes affects ____ and use
Appearance
Egg substitutes are lower in…
-Fat
-Calories
-Cholesterol
When cooking with egg substitutes, there will be color added in the form of _____, and flavor differences compared to fresh eggs
Carotenoids
Effects of keeping eggs in the fridge too long:
-Loss of carbon dioxide makes eggs more alkaline
-Whites become watery and yolk flatten
-Odors are absorbed
Milk is made up of ___% water, ____% fat, and ____% carbohydrates (lactose)
87; 3.7; 4.9
