fnu 232 chapter 7 and 8

get a hint

hint

lard is a

lard is a

pork- based fat

butter is a fat that comes from

cows

whipped spreads are half

the calories of margarine bc air has been added

types of fat include:

lard, butter, margarine, whipped spread

margarine is made from

vegetable oil that's been hydrogenated

hydrogenation

adding hydrogen to break double bonds

winterizing

salad oils are chilled to 45 degrees F and then filtered to remove any crystals that have formed

cold storage retards

hydrolytic rancidity

how does cold storage extend shelf life?

it slows down enzymes

what develops in cold temps?

fat crystals

butter, margarine, and lard can be affected by volatile flavor absorption, which means it

loses taste and may take on taste of other foods

what texture qualities are important when determining palatability?

tenderness and flakiness

plasticity

ability of a fat to be spread easily into quite thin films

surface area

ability to cover a large area (oil)

what are ways to preserve oil?

covering, patting dry foods, decreasing time in heat, straining the oil

what are the two types of frying?

shallow frying and deep- fat frying

fats are used to enhance palatibility by modifying ___________, __________, and ______________ by promoting tenderness

texture, color, flavor

how long can shortening and salad oils usually be stored at room temperature without becoming rancid?

weeks

the melting point of fats is determined by the

number of carbon atoms and the amount of unsaturation in the fatty acids

what happens to fats and oils for the commercial market?

they are rendered or extracted from their animal or plant sources, after which they are refined and sometimes hydrogenated to convert some oils into solid fats

what is done to achieve desired mix of fats and oils to achieve a fat that is stable?

blending and tempering

what is the most desirable fat crystal?

B'

polyunsaturated fatty acids do what better than saturated fatty acids?

spread

what does extended heating of fat do when frying?

causes the glycerol molecule to split from the fatty acids causing the oil to breakdown and smoke

why does rancidity develop?

result of oxidation of hydrolysis during extended storage of fats

monoglycerides and fatty acids with at least 1 double bond will help

block water from gluten by collecting at the interface btwn. the fat and the water

Fatty acids polymerize as heating continues, causing

increased viscosity of the oil (smoke point drops)

what are principles of preparations of salads?

freshness, cleanliness, and quality of ingredients and careful preparation

what are the two types of salads?

tossed (mixed) and composed (unmixed)

salads can provide a _________________, or a ________________.

main meal, side dish

satiety value

ability to satisfy hunger

what are the 4 aspects of a salad?

appropriate plate/bowl, use of a lettuce cup or other liner, main body of the salad, possible use of garnish

what are complementary aspects used in salads?

herbs and spices

what are the two main textures in salads?

crisp vs. soft

types of salads

fruit, vegetable, gelatin, high- protein

how to remove dirt and sand from vegetables?

cold water bath, rub dirt off with rag

examples of protolytic enzymes

papain in papaya, bromelain in pineapple, actinidin in kiwi

discontinuous phase

(dispersed)- droplets in an emulsion

continuous phase

liquid surrounding the suspended droplets in an emulsion

temporary emulsion

emulsion that separates very quickly into 2 layers

semipermanent emulsion

viscous emulsion containing an emulsifying agent that rarely separates into 2 layers (remain intact for a few days)

what is an example of an emulsifying agent?

egg yolk (contains lecithin)

what is an example of a permanent emulsion?

mayo (oil in water)

cooked salad dressings require only

30 % oil or more which reduces the cost and calories

what is the main thickening agent in cooked salad dressing?

starch and egg protein

cooked salad dressings must be brought to

160 degrees F

most salad dressings contain

an oil, an acidic liquid, and seasonings

emulsion

colloidal dispersion of 2 immiscible liquids, with 1 type of liquid being dispersed as droplets in the other type of liquid

salad dressings usually have droplets of oil ( ____________ phase) suspended in water ( __________________ phase)

discontinuous, continuous

emulsions are classified on the basic or their stability or tendency to

separate in 2 distinct layers: oil layer floating on water layer

dressings for salads usually are emulsions of

oil and vinegar, plus optional ingredients to alter viscosity and flavor

three main types of greens

spinach, Bibb or leaf lettuce, iceberg lettuce

why are gelatin salads popular?

thy can/ should be prepared a day in advance of a meal and still be of excellent quality, they are ideal for holidays when prep. time is limited

garnishes

intended to accent color and flavor in a meal (not a main feature); quite small

what do greens require to give the desired crispness?

high concentration of water in their cells

why is it important to remove most of the water before putting greens in salad?

bc the dressing will be diluted by the moisture and will reduce the vibrant flavors

the pressure of water within the cell exerts pressure against the walls, helping to _________________________. The greater the amount of water in the cell, the greater is the ____________________________. This pressure creates _______________, which is a state of tension in the walls.

hold them in an extended position, push against the cell walls, turgor

what does loss of water from the cells do?

reduces the tension, cells begin to collapse, greens lose their crispness and begin to droop

what are two factors controlled to reduce amount of water required to achieve saturation?

volume and temperature of air

cold air will become saturated with a __________ amount of moisture, warm air will cause ________________________ of water from greens before becoming saturated.

small, considerable loss

where should greens be stored?

very small (chilled) area

how can dressing being added cause a cell to lose its turgor?

result of unfavorable osmotic pressure that develops when the greens are in contact with the dressing and its salts for a period of time. water will be drawn from the cells into the dressing in a vain attempt to equalize the concentration of both sides of the semi- permeable cell walls

why can't fresh or frozen pineapple, fresh papayas, and kiwis be used in gelatin salads?

enzymes in them react with gelatin proteins

gel

solid forms the continuous phase and a liquid is the discontinuous phase

sol

discontinuous phase is a solid and continuous phase is a liquid

gelatin _____ is broken down and a _____ is created that can only be served as a soup

gel, sol

gelatin salads need to be _______________ before serving

unmolded, (should be done at least half an hour before serving)

in temporary emulsions, the physical act of ________________ breaks oil phase into small droplets, but droplets _______________ with each other and quickly from oil layer when allowed to stand even briefly

shaking, coalesce

permanent emulsions are stabilized by an

emulsifying agent (usually egg yolk)

an emulsifying agent is capable of

forming a protective coating around the spherical surface of each oil droplet, which blocks coalescence, thus preventing oil in one droplet from directly touching the oil in another droplet

lecithin

compound attracted to both oil and water; aids emulsion formation by forming a thin protective coating around the oil droplets

permanent emulsions can be broken by

adding too much oil, freezing, or by storage in a very warm place

two types of animal fats

lard and butter

fats are composed of

glycerol and fatty acids (usually 3) in each molecule

lipids

including fats, oils, and some other organic compounds containing carbon and hydrogen and only a very small amount of oxygen

the tendency of lard to become rancid can be retarted significantly by

storing lard in the refrigerator

milk is churned until the

original oil in water emulsion in milk breaks and butter, a water in oil emulsion forms

although a considerable amount of water is removed from butter, the end product still contains about

16%, a distinct contrast to lard which has no water

ghee

very carefully clarified butter from which the water and milk solids have been removed by heating and filtering

oils from plants are ____________ to change them into spreadable solid fats

hydrogenated

hydrogenation of the unsaturated fatty acids causes

some trans fats to from

trans fatty acid

form of fatty acid sometimes created when hydrogen is added to a double bond in an unsaturated fatty acid

why are soft margarines in tubs?

they contain such a high proportion of polyunsaturated fatty acids that they won't remain in the form of a molded stick at room temp.

both butter and margarine can be whipped. what does whipping do?

adds air and increases the volume of these spreads, contains half as many calories

the key component to making some butter- like soft spreads is either a phytosterol or stanol ester which are

plant compounds occurring naturally in some plant oils that can help reduce LDL and total cholesterol levels

shortenings don't become rancid as readily as lard, which makes it possible to

store them at a cool room temperature

oils from plant sources are generally high in

polyunsaturated fatty acids, although olive and palm oils are rather low

what contributes to oils stability at high temps?

the absence of water

what do all oil types contain?

an emulsifier (lecithin) and a propellant

glycerol

alcohol containing 3 carbon atoms and 3 hydroxyl groups

fatty acid

organic acid containing between 4 and 26 carbon atoms; combines with glycerol to from a fat

fats containing fatty acids with _____ or more carbon atoms will be ________ at room temp. than those with short chains bc of the difference in ____________ of the fatty acids

16, firmer, melting point

each carbon atom within the fatty acid chain is capable of holding _____ hydrogen atoms. when this ends, the fatty acid is _______________, which means it can't hold any more hydrogen.

2, saturated

adjacent carbon atoms will each have only ____ hydrogen atom, creating a double bond or an ________________________.

1, unsaturated fatty acid

many plant oils contain molecules of fat that have fatty acids containing ___ or ____ double bonds, which means ____________________.

2,3, polyunsaturated

what does an increase in amount of unsaturation do?

lowers the melting point temperature

the configuration at a double bond that causes the chain to continue in its linear fashion is a

trans form

the cis form is the

arrangement causing a change in the direction of the molecule at the double bond

cis form causes the melting point to be __________________________ than the fatty acid in the trans form

significantly lower

rearranged lard

lard that has been processed to remove the fatty acids from the glycerol and then to reunite the molecule in a somewhat different configuration to achieve a product that tends to form B' crystals