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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
