NUTRITION 1401 baylor Final 2024

Structural components of eggs and purpose of each

1: Yolk- 30% of eggs weight, fat; red germinal disc

2: Albumen (water/protein)- 58% of eggs weight, Chalaze; anchor yolk to the middle. Vitelline Membrane: membrane around yolk

3: Shell Membrane- between the egg white and shell; protect cell from bacterial invasion

4: Air Cell- at the larger end of the egg

5: Shell- color indicates hen breed, pores for air exchange, cuticle seals pores

How egg structure changes with aging

Thinner albumen, larger egg size, thinner egg shell

Inspection and grading of eggs

Grading: optional, (AA and A) sold to consumers, Uses candling to observe appearance

Inspection: required

Candling, Haugh units

Used for grading of eggs. Hold the egg up to the light to view its contents.

Haugh units: freshness (AA, A) is determined by cracking the egg and viewing the height of the thick albumen

Egg substitutes/ value-added eggs

"lower cholesterol", ultrapasterized, higher sodium.

-changing hens diet for nutrients (omega 3, low cholesterol, vitamins up to 300%)

Nutritional content of an egg

7 g protein, 75 cal, 5g fat in yolk, 186 mg cholesteral

Functions of eggs in food

emulsifying, binding, foaming, color, interfering (block crystal formation), clarifying (make liquids clearer)

How to create a good egg foam

room temperature beaters and utensils, avoid pourous plastic.

Fluid increases volume, decrease stability

sugar: stabilizes, add at end

acid: whips easier

Effects of cooking eggs

keep temp low, and cook time short.

Eggs coagulate at 140F

Overcooking: sulfur in egg yolk combines with iron= green

Different egg preperations

Fresh eggs are harder to peel than older

-coddling: egg in simmering water until cooked

Egg storage

stays fresh for a month, store upside down. Do not wash

Characteristics of food that make it susceptible to spoilage

Biological Changes- microorganisms (bacteria, yeasts, molds)Chemical Changes- enzymes breaking down result in the formation of a new compoundPhysical changes- water drip, evaporation, separation

Goals of food preservation

1. keep food from rotting/being inedible

2. keep foods safe to eat

3. Keep food edible and appetizing

4. Maintain nutrition

Fermentation

Microorganisms (yeast, mold, bacteria) transform a raw material into an easily preserved formChemical reactions; 1. Acids are produced 2. Flavor changes

Canning

Canned foods are heated to ensure all microorganisms are destroyed and destroy enzymes that deteriorate food. - It Protects food from harmful microorganisms and natural spoilage

Why refrigeration slows food spoilage

Slows the growth of microrganisms and moisture loss. Limits the amount of oxygen avilible to a food.

Freezing

0 degrees F or below. It makes water unavailable to microorganisms. Bacteria inactive NOT killed, some parasites are killed

Problems;

1. Freezer burn

2. Cell rupturing-(Foods with high water content shouldn't be frozen/ Rapid freezing with liquid nitrogen within minutes)

3. Fluid Loss

4. Recrystallization

Dry heat v. moist heat on tenderness

Dry heat: roasting, broiling, grilling, frying on TENDER cuts to minimize shrinkage

Moist heat: braising, simmering, stewing, steaming on tougher cuts of meat (exercised muscles)

Safe preparation for poultry

-Don't wash prior to preparation, too risky for cross contamination

-Thaw in the fridge never on the counter

White v dark meat poultry

White: not overall lower in fat than lean meat UNTIL skin is removed

Dark: more myoglobin, juicier

Milk

Water- Primarily water

carbs- from lactose

fat- flavor, mouthfeel

protein- caesin (80%, and whey)

and minerals

Caesin v whey

Caesin: (80%) Not water soluble, dispersed in milk micelles. Can be precipitated by lowering pH with acid or certain enzymes

Whey: Watery portion removed from curd consisting of water, lactose, and whey proteins

Cheese making

1. Drain the whey portion

2. Remove moisture from remaining curd

-Cheese is produced by coagulating the milk with an acid or enzyme

Types of coagulation

By adding an enzyme or an acid, caesin coagulate

Aging cheese

Cheese flavor strengthens as it ages

-Curing: aging in controlled conditions of temp. and humidity

-Ripening: Chemical and physical changes over long time

What makes something a fruit v. a vegetable

Vegetable: Plant who's parts are used for food

Fruit: The edible part that develops from a flower, contains seeds. The mature ovaries of plants

(Drupes;pit) (Pomes;seed in center)

Plant cell structure

pectins;

cellulose;

lignin;

All part of the cell wall of plants

Chlorophyll

Makes photosynthesis possible

Low pH: gray-green,

High pH: bright green

anthocyanin

flavanoid; red cabbage

Low pH: red

High pH: purple/blue

anthoxanthin

flavanoid; potatoes

Low pH; white

High pH: yellow/white

Blanching

deactivates enzymes that affect color , flavor of plants

place plant in boiling water, then ice water

Pectins

polysaccharides that act as cement between plant cell walls, structure and firmness

Acids in fruits

tartaric- grades

malic- apples

citric acids- in tomatoes and citrus

provide tartness

decreases as they ripen

<5

Phenolic compounds

browning and bruising that occurs with ripeness

tannins

in unripe fruit, makes it bitter and astringent mouthfeel

phytochemicals

nonnutritive component in plants considered to have health benefits

-suppluments

Grading of F&V

difficult because quickly changing

fruit juice labeling

juice 100%

juice drink no less 50%

nectar

ade

drink not less than 10%

Fruits after heating

Loses solutes and cells can freely pick up liquid

cell membrane and pectin breaks down, cellulose degrades

Goals with F&V preperation

-minimal nutrient loss

-little water

-little cuts, leave skin on

-only cook to doneness

Ethylene gas

a hormones tomatoes produce to ripen and turn red. tomatoes

Goal of F&V storage

to slow respiration and moisture loss

-crisper drawer, plastic bags with holes

How to limit enzymatic browning

blanching, reduce pH/temp, cover with water

Danger zone

40F-140F where bacteria can grow and cause foodborne illness

Proper thawing

maintain foods below 41

refrigeration

under cold water

in microwave, if immediately cooking

Subjective v Objective food evaluation

Subjective: Personal preference on sensory evaluation

Objective: based on measurable data and chemical properties

Using senses to evaluate food

First is sight

taste is most influentia; factor

Dissacharides and monosaccharides in food

di: sucrose maltose lactose

mono: glucose fructose galactose (6C)

ribose (5)

Complete v Incomplete protein

Complete: all 9 essential AA

Dry heat v. moist heat cooking

Dry heat can reach higher temp. oven can go up to 500F.

glass pans cook quicker, decrease 25 degrees

Moist: softens and tenderizes

Conduction

The direct transfer of heat from one substance to another that it is contacting

Convection

transfer of heat by moving air or liquid currents through and around food

Radiation

Transfer of heat energy in form of waves of particles moving outward from their source

Part of cereal grain

Husk: protective outer layer, not consumed

Bran covering: fiber

endosperm: starch, 83% of grain

Germ: fat, makes it spoil

caryopsis:

Flour

fine powder from crushed endosperm

Gluetn

structure and elasticity,

Which grains are gluten free

quinoa, rice, milet, buckwheat, sorghum

Enrichment

replenishes nutrients lost during processing. adding vitamin B and iron back into wheat

fortification

adding additional nutrients that weren't there prior

biological leaveners

yeast and bacteria; CO2 produced

chemical leaveners

baking soda or baking powder

physical leaveners

air and steam

quick breads v yeast breads

quick: made with leavening agents that allow immediete baking

yeast: must be kneaded before baking

Proofing

the yeast produces CO2, dough doubles in size

gel formation

occurs before gelation, amylose gels, semi-solid paste as gel cools

retrogredation

amylose and amylopectin molecules realign/retrograde as starch cools

dextrinization

break down of starch molecules to smaller with dry heat. sweeter

Sucrose

60% of sugar

glucose and fructose

invert sugar: hydrolyzed into sucrose+fructose

from sugar cane and beets

lactose

extracted from whey

least sweet disaccharide

aids in browning

filler in pharmaceutical products

maltose

malt sugar

flavor and coloring in beer

fructose

sweetest

45% and up is HFCS

causes stickiness and overbrowning in cooking

sugar alcohols and nonnutritive sweeteners

alcohol counterparts of carbs

provide sweetness with minimal calories

better for teeth

much sweeter than sucrose by weight

why is corn syrup used

cheap and super sweet

functions of fats in food

energy, flavor, texture, mouthfeel

shortening power, heat transfer, emulsions

satiety

Condition of being too full or too satisfied

hydrogenation

The process of converting unsaturated fats to saturated fats by adding hydrogen

-allows oil to be heated at higher temps without smoking

unrefined oil

stronger, nutty flavors

flavors will stand out; stir fry

refined oil

mild taste and smell, higher smoke point. high heat cooking

salad dressing

types of cakes

shortened, unshortened (foam), chiffon (fat and egg white)

functions of ingredients in cakes

fat- limits gluten formation

sugar- holds in moisture

eggs- emulsifier and structure

milk- steam for leavening, baking soda reaction

why are cookies crisp

more fat and sugar, lower moisture

high fat so little gluten formation

laminated v unlaminated

unlaminated- fat is cut into mixture

laminated- fat folded in, flakier

flakiness v tenderness

flaky- fat distributed through the flour

tender- fat coats the flour to prevent gluten development

inspection v grading

inspection- required to determine safety

grading- volumtary