Domain I: Principles of Dietetics Flashcards
Nutritive value of Fruits and Vegetables
- 75-93% water, carbohydrates (digestible and indigestible)
- Some minerals (calcium in oranges, greens), vitamins C, A, some B
Structure of Fruits and Vegetables
crispness (state of turgor) is due to the osmotic pressure of water-filled vacuoles
Fruits- chemical changes due to enzymes during ripening
Starch changed to sugar;
protopectin converted to pectin (ripe fruit) then converted to pectic acid (overripe fruit)
What gas accelerates ripening of fruit during storage?
Ethylene
At what temperature should frozen fruit be stored?
At or near 0F
At what temperature should dried fruit be stored?
Room temperature
Which fresh fruits are best stored at room temperature?
Avocados, bananas, pears, and tomatoes
What is the method for delaying apples aging through a controlled atmosphere?
Reduced oxygen
Climacteric fruits
Ripen post-harvest (peach, pear, banana, apple, tomato)
Non-climacteric fruits
Best when ripened before harvest (grapes, melon, citrus)
Chlorophyll
- green
- insoluble in water
What happens to chlorophyll in acid?
Turns olive green; pheophytin
What happens to chlorophyll in alkaline?
Turns bright green and mushy; chlorophyllin; hemicellulose broken down
Carotenoids
- yellow, orange
- insoluble in water
- little effect in acid or alkaline solution
Lycopenes
- type of carotenoid
- antioxidant
- phytochemical
Anthocyanins
- flavonoids
- red, blue, purple
- soluble in water
What happens to anthocyanins in acid?
turn bright red
What happens to anthocyanins in alkaline?
turn bluish
Anthoxanthins
- flavonoids
- colorless, white to yellow
- soluble in water
What happens to anthoxanthins in acid?
bleaching effect
What happens to anthoxanthins in alkalines?
turn yellow
What happens to anthoxanthins when cooked in an aluminum pan?
Turn yellow, flavones chelate aluminum
Preparation and processing of fruits and vegetables (raw)
- wash to remove dust and spray residues
- berries and mushrooms should be washed just before serving
How do you prevent the rapid darkening of fruits low in vitamin C when cut due to enzymatic action?
- dip in citrus juice,
- add sugar before freezing,
- heat to boiling
How much juice will one dozen oranges yield?
One quart
Preparation and processing of fruits and vegetables (cooked)
- softens cellulose
- increases keeping quality
- cooks starch
When sweetener is added to liquid of packing juice, what is the density of the syrup expressed as?
- % weight of sucrose
- measured in degrees Brix by a Brix hydrometer
- On label as extra light, light, heavy, extra heavy syrup
What is coulis?
Thin puree of fruit and vegetables, sugar, and water; used as a sauce
What is a compote?
fruit cooked (stewed) in syrup
Potatoes have phenolic compounds which cause color changes in raw, peeled, or bruised potatoes
- Green color under skin- due to chlorophyll that develops when potato is exposed to light during storage. May be accompanied by solanine, a natural toxicant
- Starch changes to sugar during storage (changes in taste, color, and texture) Old potatoes taste sweeter, cook to darker brown (Maillard reaction), and are softer in texture
Fruits and Vegetables
Cooking methods-boil
- small amount of a salted water for a short time, covered pan unless otherwise indicated
- Acidic vegetables that need more time to cook: use more water, no lid
Fruits and Vegetables
Cooking methods-steam
perforated container, covered, over boiling water
Fruits and Vegetables
Cooking methods-pressure cooking
retains color, flavor; cut small
Fruits and Vegetables
Cooking methods-stir-fry
use tender vegetables, high in moisture; don’t drain
Fruits and Vegetables
Cooking methods-frozen
shorter cooking time than fresh because blanching and freezing have made them tender
Fruits and Vegetables
Cooking methods-blanching
immersion in boiling water for a short time
Cauliflower preparation suggestions
cook for a short time, covered
Broccoli preparation suggestions in microwave
less time, same flavor, slightly better retention of color, better retention of vitamin C, no large difference in eating quality
Cabbage preparation suggestions
minimize the development of a strong flavor: cook for a short time, keep lid off initially to let acids escape, cook in large amount of water
Can sizes: #10
6/case
6 lbs 9 oz
13 cups
20-25 servingss
Can sizes: #3
12/case
46 ounces
5 3/4 cups
12-15 servings
Can sizes: #2 1/2
24/case
1 lb 13 oz
3 1/2 cups
6-8 servings
Can sizes: #2
24/case
1 lb 4 oz
2 1/2 cups
4-6 servings
Can sizes: 300
24/case
14-16 oz
1 3/4 cups
3-4 servings
Flavor of vegetables
- sugars in peas and corn
- glutamic acid found in young vegetables- used in form of salt (MSG)
- sulfur- onion, cabbage; when cut, enzymes and sulfur are mixed; cook Brussel sprouts uncovered with little water for best flavor
Flavor of fruits
- Due to acids, sugars, aromatic compounds
- tannins cause astringent feeling in mouth (unripe banana)
Grades USDA fruits and vegetables- based on
- quality
- firmness
- color
- maturity
- freedom from defects
- uniform size and shape
Grades USDA- canned fruits and vegetables
Grade A- desserts, salads (Fancy)
Grade B- processed (Choice)
Grade C- pudding, pie (Standard)
Grades USDA- fresh produce
Fancy, Extra #1, #1, Combination, #2
Myofibrils
bundles of fibers muscle is composed of
Sheet of connective tissue holding muscle fibers in bundles
- collagen
- elastin
Collagen
structural part of tendon that surrounds muscle; in heat- hydrolyzed to gelatin, becomes tender
Elastin
resistant to heat, little change in cooking
Sheet of connective tissue holding muscle fibers in bundles
- collagen
- elastin
Meat, poultry, fish-fat structure
deposited around organs, muscles, in muscles (marbling); finish-amount of fat cover on carcass
Meat, poultry, fish-shape of bone
identifies cut: round bone-leg, T-bone- back and ribs
Nutritive value of meat, poultry, fish, meat alternative
- 16-23% protein
- carbohydrate- glycogen in liver, glucose in blood
- vitamins, minerals- thiamin, niacin, riboflavin, iron, copper, trace minerals (pork is a good source of thiamin)
- calcium content is high in fish canned with bones, oysters, shrimp
Pigments in meat
Myoglobin + oxygen -> red -> brown -> green
(green colors are due to further myoglobin breakdown)
Post-mortem changes and aging
- hold in cold storage to age and ripen- about 10 days
- aging increases tenderness
- change in muscle protein brought about by enzymes which increase the water-holding capacity of the muscle
- acid (vinegar) and salt also increase tenderness by increasing water-holding capacity of muscle
- physical activity of animal will NOT increase tenderness
Anaerobic (Sous vide)- meat storage
vacuum-packing meat in an oxygen-impermeable film, stored unfrozen at 0C; extends storage life of meat
MAP (modified atmosphere packaging) -meat storage
prolongs shelf life; air (oxygen) is removed and replaced with gasses (carbon dioxide, nitrogen); prevents deterioration by slowing respiration
Meat inspection- USDA
mandatory; done at slaughter
shown with round purple stamp “USDA Inspected and Passed”
Wholesome Meat Act of 1967
assures consumer that the animal was healthy at the time of slaughter and the meat is fit for human consumption (assures wholesomeness)
Meat grading- USDA
- indicates quality
- appears on shield
- states federally graded by Agricultural Marketing Service of the USDA
- Grades: prime, choice, select, standard (determined at slaughter)
- Based on maturity of animal, marbling of fat, color and texture of lean
- standard grades have the least marbling; prime the most
Meat specifications
- Uses a numbering system for order wholesale cuts
- IMPS-Institutional Meat Purchasing Specifications
- NAMP- National Association of Meat Purveyors
Cooking principles (meat)
- 325F for roasting
- high temperatures increase shrinkage, toughen
- a slow-cooked roast yields less waste
- insert meat thermometer BEFORE cooking
Safe minimum internal temperatures
145F pork, beef, veal, steaks, roast, fish
160F ground beef, ground veal, ground lamb
165F turkey, chicken, duck
Physical and chemical changes- meat protein
coagulates
Physical and chemical changes- meat collagen
hydrolyzed to gelatin and softens; tough cuts need to be cooked well done because they have more collagen which needs more time to soften
Physical and chemical changes- meat surface browning
due to breakdown of pigments
Physical and chemical changes- meat interior color during cooking
heat changes interior from red to pink to brown to gray; heat denatures globin; iron is oxidized
Physical and chemical changes- meat dehydration
heat to 160F before dehydrating (beef jerky)
Physical and chemical changes- cured meat
pink from nitrites (inhibit botulism)
Tempering meat
allows to cook more evenly
Methods of cooking- dry heat
no water involved, for tender cuts near backbone (loin, sirloin)
frying, broiling, roasting, grilling
Methods of cooking- frying
desirable for fat used to have high smoke point >400F
Do not fry tough cuts of meat (bottom round)
Smoke point
temperature to which fat can be heated before puffs of smoke occur
Smoke point-decreasing order
Safflower (513), soybean, canola, corn, palm, peanut, sunflower, sesame, olive (375), lard (375), shortening (365-370), butter (350)
Monoglycerides (shortening) have lower smoke points
Rancidity
the uptake of oxygen in an unsaturated fatty acid
healthiest plant oils are all highly unsaturated (olive oil has more MUS; less susceptible to rancidity than soybean oil which has more PUS)
Methods of cooking- broiling
form of radiated heat
Methods of cooking- roasting
when meat is removed from oven, “carry-over-cooking” occurs for about 10 minutes; internal meat temperature will rise 15-25F
allow roast to stand 30 minutes before carving
Methods of cooking- grilling
form of dry heat cooking
Methods of cooking- moist heat
water involved, less tender cuts with more connective tissue (bottom round, chuck roast)
braising, simmer, steam, stewing
Methods of cooking- braising
flour meat, brown, cover, and simmer in liquid; in oven or range-top
Methods of cooking- simmer
heat in water to 170-185F with appearance of bubbles
Methods of cooking- steam
heat over, not in, water
Methods of cooking- stewing
add water or other liquid during cooking
Proteolytic enzyme (papain)
tenderizes meat (blend of papaya and salt)
Meat alternative: soybeans
- methionine is the limiting amino acid
- protein concentrates: >70% protein; protein isolates >90% protein
- used in textured protein products (TVP); mixed with ground meats-extends the number of servings, lowering costs; soy protein adds juiciness because of water content
- edamame (soybean pod), tofu (coagulated soy protein), miso (paste of soy and grains), tempeh (aged soybean and grain), natto (fermented soybeans)
Fish cookery
- use dry or moist heat
- more perishable than meat so store at lower temperatures
- fresh fish should have bright red gills and bright, shiny skin
Surimi
purified and frozen minced fish with a preservative, used in analogs, may have egg white or starch added to create desired structure
histamine toxicity
linked to inadequate refrigeration of tuna, mackerel, mahimahi
Eggs-structure
- porous shell- exchanges moisture and gasses; covered with bloom that prevents excessive loss and protects contents
- color of shell is unrelated to food value or quality
- inner membrane contracts leaving air space in large end
- air space becomes larger with age
- high proportion of thick white is indicator of good quality
- yolk is surrounded by vitelline membrane, chalazae are yolk anchors
Egg-nutritive value
- 80 calories, 6 grams protein, 5 grams, fat, vitamins A, D, riboflavin
- yolk is more concentrated than white (more protein, fat, minerals, and vitamins by weight)
- fat is present in an emulsified form (egg yolk=naturally occurring oil in water emulsion)
- color of yolk depends on amount and type of pigment in hen’s diet
Egg-grades
AA, A, B
thickness of white, location and condition of yolk
viewed by candling (pass an egg in front of bright light to view contents)
Egg-grades do NOT include
color of shell, nor size of egg
Egg size
based on weight per dozen
Egg freshness
raw eggs can be stored in refrigerator at 40-45F for 3-5 weeks
Grade A eggs can be maintained for 6 months in cold storage
A fresh egg will sink to bottom in pan of cold water and has dull, rough shell
Egg coagulation
- protein coagulates at 62-70C (sets a custard)
- used to bind, gives firmness, stability, coats food, browns, clarifies liquids
Syneresis (weeping)
liquid released from a coagulated product
occurs when cooked at too high a temperature, or too low a temperature for too long a time; creates a tough, watery product
Egg-leavening
depends on amount of air beaten in an retained
1. when an egg foam is heated, air expands, egg white stretches and protein coagulates
2. acid stiffens egg white foam by tenderizing protein allowing it to stretch more easily (egg white foams compared by measuring specific gravity)
3. egg whites at room temperature have lower surface tension-whip more easily and yield larger volume
4. Sugar stabilizes egg white foam
Egg-emulsification
- lecithin helps yolk act as an emulsifier
- lipoproteins stabilize the emulsion by interacting at the surface of the oil droplets to form a layer
- mayonnaise-food emulsion stabilized by egg yolk
Methods of cooking egg-water preparation
- poaching or coddling-use high quality egg, appearance is important
- vinegar and salt improve shape by hastening coagulation
- surfaces of yolks turn green when overcooked or allowed to cool slowly due to iron from yolk and sulfur from whole egg combining to form ferrous sulfide
Methods of cooking egg-dried heat
- overcooking toughens
- undercooking results in excessive shrinkage when removed from oven
Methods of cooking egg- custards
- larger the % sag, the more tender the gel (objective measure of quality)
- custards made from dehydrated eggs, may be grayer and less yellow, have an eggy flavor, and be watery
Egg processing-frozen
- remove from shell first; can be frozen whole or in parts
- 10% salt or sugar (by weight of the yolks) are added as stabilizers
Egg processing-dried
- can be vacuum-packed in nitrogen gas
- dried fortified: 70% white, 30% yolk
- baker’s special eggs: sucrose added to improve foaming ability
Egg substitutes
- lower in fat, calories, cholesterol; often higher in sodium than fresh eggs
- when cooking with egg substitutes, there will be color (added carotenoid) and flavor differences
When eggs are held in the refrigerator too long:
- deterioration affects appearance and use
- loss of carbon dioxide makes eggs more alkaline
- whites become watery, yolks flatten
- odors are absorbed
Milk composition and nutritive value
- 87% water, 3.7% fat, 4.9% carbohydrate (lactose)
- 3.5% protein (complete, HBV); 80% casein (precipitated at pH 4.6 forms soft curd); whey is liquid that drains from curd (lactose, lactalbumin, lactoglobulin, water soluble vitamins, minerals)
- good source of calcium, phosphorous, riboflavin, vitamins A, D
- low in iron and vitamin C
Pasteurization
- destroys pathogenic bacteria
- 145F for 30 minutes or 160F for 15 seconds
- UHT (ultra high temperature) aseptically packaged milk can be stored without refrigeration if unopened
Types of milk: homogenized
high pressure breaks fat globules to 1/5 regular size; film of protein surrounds each globule
Types of milk: vitamin D milk
feed the cow vitamin D, irradiating the milk, or adding vitamin
Types of milk: 2%, low fat, skim
2% milk has 1.5-2.25% fat
low fat milk has .5%-2% fat
skim milk <.5% fat
Types of milk: concentrated
evaporated milk (60% water removed, at least 7.9% milk-fat, brown color due to caramelization of lactose during canning),
sweetened condensed milk (evaporated milk, add 15-18% sucrose or glucose),
dried whole milk (26% fat, does not keep well),
dried skim milk (<1.5% fat, condense skim milk, dry by spraying into heated vacuum chamber)
Types of milk: fermented
cultured buttermilk: add lactic acid bacteria to skimmed or partly skimmed milk, recipe= 1T vinegar or lemon juice, or 1 3/4 tsp cream of tartar + enough milk to make 1 cup, when using buttermilk in place of regular milk increase baking soda
sweet acidophilus milk: skim milk + Lactobacillus acidophilus bacteria to reduce lactose
Types of milk: fermented
cultured buttermilk: add lactic acid bacteria to skimmed or partly skimmed milk, recipe= 1T vinegar or lemon juice, or 1 3/4 tsp cream of tartar + enough milk to make 1 cup, when using buttermilk in place of regular milk increase baking soda
sweet acidophilus milk: skim milk + Lactobacillus acidophilus bacteria to reduce lactose
kefir: fermented by Lactobacillus kefir which reduces lactose
Types of milk: low lactose-Lactaid
treated with lactase in processing or add enzyme to regular milk and hold in the refrigerator
Types of milk: yogurt
coagulated product, fermentation of milk sugars by lactic acid bacteria
Types of milk: filled milk
skim milk, vegetable fat (coconut oil), water, illegal in some states
Types of milk: imitation milk
resembles milk but contains neither milk fat nore other important dairy ingredients
made from casein derivatives or soybean protein and vegetable oils
When milk is heated, whey protein:
precipitates out on bottom of pan or on surface of milk
To prevent a film from forming when heating milk
cover or beat the milk to produce foam
To prevent milk from coating sides of pan
heat over water
To prevent curdling
add acid slowly and agitate, acid precipitates casein
Butter vs margarine fat percentage
butter- 80% milk fat; margarine- 80% vegetable oil or animal fat
Hydrolytic rancidity
Uptake of water leads to flavor changes in butter (saturated fat)
Oxidative rancidity
Uptake of oxygen at a double bond in an unsaturated fat
Cream % fat
heavy or thick >36%
medium 30-36%
whipped cream 35%
light or thin 18-30%
sour cream >18%
half and half no less than 10.5%
Cheese production
warm milk, add lactic acid bacteria, add enzyme rennet to coagulate casein forming th curd, separate curd from whey
Cheese types
- uncured-refrigerate immediately (cottage cheese, cream cheese)
- cured- additional whey removed, salt added, ripened
- % moisture content high to low: cottage (79), cream, mozzarella (45-55), camembert, bleu, Swiss, cheddar, parmesan (31)
- processed- blend of several natural cheeses + emulsifier, fat will not separate out, high moisture content (41-50%)
To prevent stringy, curdled-looking cheese products
cook for short time at moderate temperatures
Flour, grains, and cereals: structure
starchy endosperm rich in protein, outer layer of hull, and bran
scutellum in germ has most thiamin
Flour, grains, and cereals: nutritional value
75% starch; partially complete protein; 2% fat-found in germ
vitamin E (in germ), thiamin, riboflavin, phosphorous
Flour, grains, and cereals: milling
air classification is a separation method that improves baking qualities by separating large flour particles from fine particles
Flour, grains, and cereals: processing of hot, ready to cook cereal
- farina-inner portion of wheat kernel
- quick-cooking cereals have disodium phosphate added: makes cereal alkaline so particles swell faster, avoid on low sodium diets
- enzyme treated for quicker cooking means the proteins have been split to lessen cooking time
Wheat flours: graham, whole wheat
entire grain, use freshly ground, spoils quickly due to fat in germ
Wheat flour: bread (hard wheat)
strong gluten; 11.8% protein
Wheat flour: all-purpose
blend of hard and soft, less gluten, 10.5% protein
Wheat flour: pastry (soft wheat)
weaker gluten, 7.9% protein
Wheat flour: cake (soft wheat)
least and weakest gluten, 7.5% protein
Wheat flour: enriched
thiamin, riboflavin, niacin, iron, folic acid
Wheat flour: instant blending, agglomerated, instantized
no pre-sifting needed
Wheat flour: self-rising
baking powder, flour, and salt
Alimentary pastes
- durum wheat-high in gluten: after bran and germ removed, starch is ground to make semolina flour, products are flexible after cooking
- noodles- contain egg yolk or egg solids
Rice cookery
- vitamins are lost when cooked in excess water or when water is drained off
- cook in an amount of water that will be absorbed during cooking (for 1 cup rice-use 2 cups water)
Functional properties of gluten (flour) in baked goods
elastic properties, forms framework, holds in leavening agent, made from gliadin and glutenin through process of hydration and mixing
strength of flour refers to capacity to retain leavening
Color due to carotenoids in baked flour mixtures
- natural agents cause oxidation during storage and turn flour from creamy yellow to white
- if an oxidizing agent is added-labeled “Bleached”
What happens to baked goods when you add bran and how do you compensate?
- decreases volume of end product
- increase flour and liquid to compensate
Functional properties of liquid in baked goods
hydrates gluten and starts its development
starts action of chemical leavening agent
dissolve salt, sugar; gelatinizes starch
Functional properties of leavening agent (steam) in baked goods
expand the hollow shell formed by flour and egg
hot oven is required to raise liquid to boiling quickly
popovers, creampuffs
Functional properties of leavening agent (air) in baked goods
air expands when heated before proteins coagulate and retain it
to incorporate air: beat, sift, fold, cream
angel cake, sponge cake
Functional properties of leavening agent (carbon dioxide) in baked goods
from action of yeast on sugar yielding carbon dioxide and alcohol
from action of acid (sour milk, cream of tartar, molasses) on baking soda (sodium bicarbonate)
baking powder (mixture of baking soda, dry acid, and cornstarch) provides both the acid and alkali needed for reaction; old baking powder is more alkaline causing loss of thiamin in baked goods
deeper brown crust: alkaline solution (baking soda) and solid sugar
Functional properties of salt in baked goods
adds lavor, keeps yeast from sticking
Functional properties of egg in baked goods
provides stability, retains leavening agent, distributes shortening by emulsification, introduces air, adds color and flavor
Functional properties of fat in baked goods
adds tenderness by coating gluten particles
Functional properties of sugar in baked goods
hygroscopic-tenderizes; softens gluten and prevents gluten development by absorbing some of the water gluten needs
too much sugar results in coarse cells, thick walls, a shiny crust and a crumbly product
most of sugar in honey is glucose and fructose
when substituting Sweet and Low for sugar in a recipe, use half as much
Methods of mixing
- use bowl with sloping sides and 1/2 full
- beat: over and over to smooth and incorporate air
- cream: work one or more foods until soft and creamy (cream fat into sugar)
- cut-in: distributes fat into dry ingredients
- fold: use in foams; a down, across, up, across the top motion, rotate bowl
- knead: used in dough; push, pull, turn
- stir: circular or figure 8 motion to blend
- whip: beat rapidly to incorporate air to form a foam
Quick breads, examples
muffins, biscuits, popovers
Quick breads, basic ingredients
egg and flour
Muffin mixing method
- sift dry ingredients; make well in center
- blend liquids and add all at once to dry ingredients
- mix just enough to dampen
Excess mixing of muffins results in:
- loss of carbon dioxide, overdeveloped gluten
- tunnels from top to bottom, tough, heavy produce
Characteristics of a good muffin
round, pebbled top, symmetrical shape, no long, narrow tunnels
Cakes-method of mixing
cream fat with sugar, add egg, add sifted dry ingredients in portions, alternating with portions of milk
Cakes-types
shortened cake (comparatively large amount of fat; uses chemical leavening)
foam cake (uses air as leavening)
Types of shortened cake
- layer cake (baking powder)
- pound cake (air and steam)
- rich cake (increased fat, sugar, egg; increases keeping quality)
- gold cake (egg yolks)
- white cake (egg whites)
- yellow cake (whole egg)
Types of foam cake
- angel cake (egg white foam)
- sponge cake (yolk foam and white foam)
- chiffon cake (liquid yolks, egg white foam, baking powder, oil)
Crumb structure depends on:
ingredients, procedure used, pan shape and size, baking temperature, time elapsed before baking
Cake-alterations in the amount of sugar
the more sugar, the more time is needed to reach the elevated coagulation temperature of the gluten
As sugar increases, the volume of cake increases up to the point where volume is so great, and gluten so weak, that the gluten strands snap and the cake falls in the center
gummy, crystalline appearance
What causes a cake to yellow?
alkaline batter (excess soda)
What causes a cake to have a fallen center?
excess sugar, excess fat, excess baking powder
What causes a cake to have a tough, dry crumb?
too much flour or egg, too much mixing, too little fat or sugar, over-baking
What causes a cake to have a coarse texture?
too much baking powder or sugar, oven temp too low
What causes a cake to have poor volume?
too little baking powder, improper level of sugar or fat
Cookies
modified shortened cake; higher in fat, lower in sugar and liquid
Pastry
flour, fat, liquid, salt
Substituting butter for lard in pastry
lard and oil are each 100% fat; butter and margarine only 80% fat
when substituting butter for lard, need to use more
Pastry, mixing method
cut fat into flour and salt, add liquid
avoid over-handling
bake at 425-250F for 10-15 minutes
How do you increase tenderness in pastry?
enhance by using oil, soft fats, or fat cut into very small pieces
How do increase flakiness in pastry?
leave fat in coarse particles (fat pieces melt and leave a hole where steam collects)
How do you bake meringue on top of lemon pie?
spread meringue on warm to hot filling, bake at 425F 4-5 min
Liquid to flour ratios of: pour batter, drop batter, soft dough, stiff dough (and examples)
pour batter 1:1, waffles
drop batter 1:2, muffins
soft dough 1:3, bread
stiff dough 1:4, pie crust
What type of batter absorbs the most fat when deep fried?
high fat, high sugar
What types of flour absorb less fat during frying?
all-purpose and bread flours absorb less fat than cake flour
Yeast dough
- use high protein flour (low protein flour causes crumbly products)
- yeast ferments sugar releasing carbon dioxide
Straight dough method-yeast dough
all ingredients are added before dough is allowed to rise
Sponge method-yeast dough
combine liquid and part of flour and allow to ferment for several hours; add other ingredients and knead
proofing time is shortened
Continuous baking method-yeast dough
reduces processing time, not as affected by fermentation time and temperature
commercial process that substitutes intense mechanical energy to a large degree for traditional bulk fermentation
Baking at high altitudes
- steam forms earlier
- decrease amount of baking powder, increase amount of liquid
- longer cooking time required (boiling temperature drops 1F for every 500 foot rise)
Two types of starch molecules
amylose and amylopectin
Amylose
responsible for gelation of cooled, cooked pasta
not branched
Amylopectin
branched: 1,4 and 1,6 alpha glucosidic linkages
waxy starches (corn, rice, sorghum)
non-gelling: stable to freezing and thawing, used in frozen foods (corn starch used most often)
Thickening ability of starches in order of effectiveness (most to least)
potato, waxy corn, waxy rice, waxy sorghum, tapioca, wheat starch, wheat flour
(wheat flour less effective than wheat starch because of protein content; more protein=less effective)
Gelatinization
the swelling that occurs when starch is heated in water close to boiling point.
Heat dissociates bonds, water moves in and swells granules.
Friction is created causing paste to thicken
Role of sugar in gelatinization
- competes with starch for water
- increase translucency, reduces viscosity and gel strength
- if too much sugar is used, consistency is thin
Acid effect on gelatinization
breaks down starch producing runny product
if necessary, add when cooking is complete
Retrogradation
starches revert to insoluble form on freezing or ageing, hydrogen bonds holding gel together break causing gritty texture
stale bread, separation of when gravy thaws
more common with higher proportion of amylose
Modified starch
chemical modification: by acids and enzymes to change viscosity and ability to gel
physical modification: pre-gelatinized starch used in instant pudding
used to stabilize frozen gravies, waxy maize, modified cornstarch
Starch uses in food preparation-dry heat
starch molecules break into fragments called dextrins-dextrinization
color change occurs (browning of toast)
Starch uses in food preparation-moist heat
- starch granule in cold water don not dissolve, form a suspension
- to prevent lumps, mix starch with fat, cold water, or sugar
- heat, acid, and agitation will affect the stability of swollen starch granules in a paste
White Sauce
- melt fat, add flour (roux-half fat, half flour)
- remove from heat, add liquid at 170-180F; add salt
- add an acid when cooking is complete
- to get a clear, shiny, translucent sauce, use cornstarch as thickener
- if product is starchy tasting and grainy-due to uncooked flour
- souffle is an example of a thick white sauce
Crystallization in food preparation-preparation of crystalline candies
heat sugar and liquid to dissolve. heat further. crystallize under conditions that produce small crystals which have a smooth, creamy feeling
How to control crystal size-crystal inhibitors
(keep crystals small and smooth)
1. Acid-cream of tartar, vinegar
-sugar and acid combine to promote inversion (hydrolysis) of sucrose
-end products are equal amount glucose and fructose (invert sugar)
2. fat-chocolate, milk
3. protein-milk, egg whites, gelatin
Candies-ingredients
sugar, water, corn syrup or cream of tartar
Candies-progression of look and texture
viscous, shiny and smooth at start of process then becomes creamy, dull, lighter in color. With further beating, cools and stiffens rapidly
Candies-types
- crystalline sugar-fixed orderly pattern of molecules or atoms (large crystals-rock candy; small-fondant, fudge)
- non-crystalline sugar- amorphous, glasslike (crystallization prevented with interfering substances or increased sugar concentration; hard candies, brittles, chewy candy, gummy candies)
Ice cream-overrun
increase in volume from freezing and whipping
determined by weight; should be 70-80%
Ice cream-homogenization
makes ice cream smooth by making it easier to beat in air during freezing
Ice cream-agitation
is essential to keep ice crystals small and to incorporate air
Process for making ice cream
hydrate gelatin in cold water then heat
Ice cream- crystal inhibitors
- fat- not adding enough fat produces a grainy texture, increase fat to produce smoother ice cream (heavy cream instead of light cream)
- egg
- gelatin
- nonfat milk solids
Mellorine
imitation ice cream; butterfat replaced by hydrogenated vegetable oil
Gelatin-nutritive value
4 calories/gram; incomplete protein-no tryptophan, low in methionine and lysine
Gelatin-properties and uses
- changes liquid into elastic solid
- acts as a foaming agent in marshmallows
- keeps sugar and ice crystals small in candy and ice cream by interfering with the union of small crystals to make large ones
Gelatin-gel formation
1 T gelatin will gel 1 pint liquid, mix with cold water to soften, add hot water to disperse
Increase gelatin or decrease liquid when:
- making a large mold
- it will stand at room temperature for a long time
- acid content is high
- making a whip
Enzymes that prevent gelation
bromelain (pineapple) and papain (papaya)
What temperature is best for brewing coffee
185-203F; higher temperature-tannin is extracted and coffee is bitter
Percolator
single container, covered basket with stem; gives stronger and bitter coffee; water is hotter and repeatedly passes through grounds
Dripolator
three separate compartments; add boiling water to top and let drip through; brief contact with ground; free of bitterness
Vacuum brewed
higher temps than recommended
Decaffeinated coffee
process uses methylene chloride
Food additives
FDA controls
emulsifiers, sorbitol, stabilizers/thickeners, anti-caking, nitrites, mold inhibitor, antioxidants, flavor enhancer
Examples of emulsifiers
- monoglycerides
- diglycerides
- lecithin
- disodium phoosphate
Reasons for adding sorbitol
humectant (retains moisture)
sweetener
bulking agent
limits mold
Examples of stabilizers/thickeners
pectin
cellulose
gelatin
gum
agar
carrageenan-prevents chocolate from sedimenting in fat free milk
Examples of anti-caking
Calcium silicate
mannitol
Reasons for adding nitrites
fixes color
inhibits spores of clostridium botulinum
Examples of mold inhibitors
propionate
sodium benzoate (soda)
Examples of antioxidant additives
propyl gallate
BHA
BHT
ascorbic acid
alpha tocopherol (natural)
Examples of flavor enhancer additives
MSG-monosodium glutamate (provides umami, savory taste)
Qualitative sensory evaluation of food
uses organoleptic measurements (sense organs) to test color, odor, taste, texture
Analytical sensory evaluation of food
difference or discrimination tests
-paired comparison test- two samples side by side to compare specific quality
-triangle- three samples, determine which two are identical, tests differences between new and old products
-ranking or scaling- classify differences in color, taste; rank in order of preference
Affective sensory evaluation of food
determine preference, acceptance, or opinions of a product
-hedonic rating-scale; facial hedonic-smiling faces
-paired preference-compares two samples for preferences of a specific attribute
-ranking test-extension of paired preference; additional samples
Flavor profile method of sensory food evaluation
trained panel
analyze and record aromas and flavor in great detail
Pentrometer
tenderness firmness; baked custards (objective measure)
Viscosimeter
objective measure of viscosity on an incline plane or rotational basis
Line-spread test
objective measure of viscosity on a flat surface
Specific gravity
objective comparison of lightness of products (egg white foams); ratio of the density of a food to that of water
GMO
scientific techniques used to produce specific desired traits in plants, animals, or microorganisms through the use of genetic knowledge
GMO crops
corn, soybeans, canola, papaya
GMO results include:
plants more resistant to disease, insects, weeds
plants that require less water
extended shelf life
improved efficiency of food production
Food synergy
the additive influence of foods and constituents which, when eaten, have a beneficial effect on health
Probiotics
live microbial food ingredients that benefit health (kefir, acidophilus milk, yogurt)
promote healthy microbial balance in intestine, may stimulate activity of immune cells and reduce gut inflammation
Prebiotics
nondigestible food ingredients that support growth of probiotics
1. fibers (FOS, soluble dietary fiber, found in onions, garlic, asparagus)
2. inulin (fructose polymer)
Functional foods
provide more functions than the basic nutritional benefits
1. conventional (whole) foods
2. modified: fortified, enriched, enhanced
3. medical foods: PKU formulas
4. special dietary use: gluten-free, weight loss foods
Phytochemicals
biologically active, naturally occurring chemical components in plant foods, act as natural defense for plants
Sources of phytochemicals
fruits, vegetables, legumes, whole grains, nuts, seeds, herbs, and spices
Possible benefits of phytochemicals
- prevention or treatment of chronic diseases
- may detoxify drugs, toxins, carcinogens, mutagens
- may act as blocking agents, preventing active carcinogen from reaching target
- may reduce risk CHD by protecting LDL cholesterol from oxidation, reducing synthesis or absorption of cholesterol
Examples of phytochemicals
- Indoles: cruciferous vegetables (sulfur)-detoxification of carcinogens
- Isoflavones: anthoxanthin in soybeans- lower elevated cholesterol
- categories: terpenes, carotenoids, lycopene, phenols, flavonoids, phytoestrogens, thiols, lignans (flaxseed)
USDA National Nutrient Database for Standard Reference
major source of food composition
FNDDS Food and Nutrient Database for Dietary Studies
use to analyze data from dietary studies
FDA Total Diet Study Database
Data on foods, minerals, chemicals
Dietary supplements database
NIH
Labeling and packaging claims
Nutrition Labeling and Education Act
FDA
label must identify: form, weight, name and address of manufacturer, ingredients in decreasing order of predominance, size of serving
Label regulations
low cholesterol= <20 mg of cholesterol/serving
low calories= no more than 40 calories/serving
calorie free= <5 calories/serving
low fat= 3g or less/serving
fat free= <0.5 g/serving
very low sodium= no more than 35 mg/serving
low sodium= no more than 140 mg/serving
low sat fat= 1g or less/serving
lean= <10g fat, <4g sat fat, <95mg cholesterol
extra lean= <5g fat, <2g sat fat, <95mg cholesterol
free= no amount, or trivial amount
lite, light= 1/3 fewer calories or 50% less fat
gluten-free= <20ppm
organic= minimum of 95% organic ingredients
Label regulations
low cholesterol= <20 mg of cholesterol/serving
low calories= no more than 40 calories/serving
calorie free= <5 calories/serving
low fat= 3g or less/serving
fat free= <0.5 g/serving
very low sodium= no more than 35 mg/serving
low sodium= no more than 140 mg/serving
low sat fat= 1g or less/serving
lean= <10g fat, <4g sat fat, <95mg cholesterol
extra lean= <5g fat, <2g sat fat, <95mg cholesterol
free= no amount, or trivial amount
lite, light= 1/3 fewer calories or 50% less fat
gluten-free= <20ppm
organic= minimum of 95% organic ingredients
%DV
% of the daily value for each nutrient a serving of the food provides, based on a 2000 calorie intake.
Includes DRV (daily reference value) and RDI (reference daily intake)
New food labels
DVs for vitamin D, potassium, calcium, iron; total sugar and added sugars; single serving packages reflect values as one serving
Food additive that does not have GRAS status
sucralose
Packaging claims
Health claims: based on authoritative statements from a scientific body of the US Government or the National Academy of Sciences
Qualified health claims
emerging evidence of a relationship, but not conclusive; requires a disclaimer
Structure function claims
may be used without FDA permission
Ineffective communication can result in incorrect diagnoses and noncompliance with treatment. Consider the following:
- Assume differences until similarities are proven
2.Emphasize description rather than interpretation or evaluation. Focus on getting a complete description of what is wanted rather than making judgments on how something was said. - Avoid stereotyping
How do cultural communication styles differ?
- Rate, pitch and volume of the voice
- Eye contact: direct gaze or avert eyes as a sign of respect
- Expression restrained, emotional, focused
- Speech: slow and soft, loud and fast
- Greetings: handshake firm, mild
Spatial relationships vary among cultures and among individuals, what are the zones?
- Intimate zone: <18” very close friends, business handshakes
- Personal zone: 18”-4’ giving instructions, working closely
- Social zone: 4-12’ most business interactions
- Public zone: >12’ very formal interaction
When working with clients with limited English:
use common terms
avoid slang, acronyms, and shorthand
use short, simple sentences
Pedagogy
art and science of teaching children
teachers are authority figures
Andragogy
adults are mutual partners in learning, more problem-centered than subject-centered, motivation is more internal than external, self-directed learner
Social Economic status effect on learning style
Middle and upper adults: goal-oriented; consider activities they can’t relate to as a waste of time
Lower income adults: interests focus on costs and traditional food habits; oriented toward present and towards solving current problems
Very Poor: short term planners
Age groups learning styles
Adolescents: relate to their interests; consider peer pressure and attitudes toward authority
Elderly: decreased attention span; audience participation to maintain interest; control questions to stay on topic; prefer written material
SMART objectives
specific, measurable, attainable, relevant, time bound
Consonance
the fit between the program and the expected outcomes based on the objectives