Lipids

Function of fat in food preparation

They give flavor and a mouthful that is associated with moistness Flavor, color, texture, tenderness, emulsification, heat transfer, control of crystallization, moistness in meat

Key Properties of fat: Plasticity

(the quality of being easily shaped or molded) -Most fats that appear to be solid at room temperature actually contain both solid fat crystals and liquid oil BC of the combination of liquid and solid, the fat can be molded or pressed into carious shapes without breaking EX. Shortening

Define rancidity and discuss the factors that encourage or discourage the development of rancidity and flavor reversion

-Definition: smelling or tasting unpleasant as a result of being old and stale -Release of free fatty acids does not produce undesirable odors and flavors in fats unless they are short-chain fatty acids, such as butyric acid and caprice acid - predominant in butter -Rancidity can be prevented or delayed by storage at refrigerator temperature with the exclusion of light, moisture and air

Structure

-Glycerol and fatty acids linked together -Monoglyceride: lipids consisting of one fatty acid to one of the hydroxyl groups of glycerol -Diglyceride: two fatty acids esterififed to glycerol -Triglyceride: three fate kids esterified to glycerol

Identify source of lard and discuss whit may be used in food preparation

-High saturated fat, lack of uniformity in production, flavor and potentially grainy texture -Definition: the fat rendered from the fatty tissues of the hog --Interesterification can be applied to improve plasticity and creaming qualities -Some lard samples have relatively low smoking temperatures and have not been commonly used for frying

Physical structure: Oils

-Liquid at room temp -Plant source -Usually more unsaturated

Identify hydrogenated fats and explain reasons fats are hydrogenated

-Saturated, monounsaturated, and polyunsaturated -Makes them solid at room temperatures, cheaper and less perishable substitute for butter

Physical Structure: Fats

-Solid at room temp -Animal source -Usually more saturated

Basic concepts of hydrogenated fats

-The process changes liquid oils into plastic shortenings or margarines -Hydrogenated shortenings are neutral in flavor, have a smoke point high enough to be used for frying and have good shortening power for baked goods -Hydrogenated fats RESIST oxidation, which results in undesirable rancid flavors and odors

Market forms: Butter

80% fat, made from cream

Market forms: Margarines

80% fat, made from vegetable oil

Functions: Emulsions (three parts)

1. Discontinuous phase: usually oil 2. Continuous phase: likely water based 3. Emulsifier: helps keep one phase dispersed in another -Emulsifying agent: lecithin (egg yolk), gelatins, protein

Market Forms: Lard and Oil

100% fat

Guidelines for Deep Fat Frying: Control time/temp

350-450 degrees F -Use a thermometer -Too high: burn food but undercooked inside -Too low: absorbs fat -Use clean lipid, heavy utensils and control surface area -Drain water and ice from surface

Why is smoking point a negative?

Acrolein: substance produced when fats are heated to excessive temperatures due to the breakdown of glycerol -Fire hazard: reaches flash point - catches on fire

Fat Replacers in baking

Pureed fruits or vegetables Yogurt Ricotta or cottage cheese Ground flax seed Mashed ripe banana

Guidelines for Deep Fat Frying: Use the proper lipid

Butter (smoke point is 260 F) Peanut, corn, and soybean (496 smoking point)

Describe butter

Butter contains approx. 80% butter fat, 18% water and milk solids Made from the fat of cream that is separated more or less completely from the other milk constants by agitation or churning

Fat Replacers

Carbohydrate based -Fibers, gums, pectin, cullose and starches -Bind with water and swell - give some of the texture and mouth feel of fat Protein Based -Whey or egg proteins -Used in meats and other products that need to be refrigerated or frozen

Clarified butter

Contains only the butter fat

Define winterized oil and discuss its use in food preparation

Definition: has a lower melting point and does not crystalize at a refrigerator temperatures process of removing the higher melting point parts of the oil -the cloudiness of these oils occurs because some of the triglyceride molecules in the oil have higher melting points than other molecules in the mixture and crystalize or become solid at the low refrigerated temperature

Describe methods of cooking that utilize fat: Frying

Dry heat cooking method Panfrying: shallow layer of fat is used -Good for meats, potatoes, veggies and eggs Deep fat frying: food is submerged in heated fat -Good for french fries, onion rings, breaded chicken tenders and nuggets Sauteeing: uses small amount of fat Temperature: -Too high: foods will be sark on outside before done on the inside -Too low: excessive fat is absorbed

Functions In cooking:

Emulsions Flavor Texture -Pastry: give flaky characteristics -Batter and dough: give soft, airy texture Non stick agent Transfer heat (deep fat frying)

Key properties of fat: Melting Point

Fat relatively has a high melting point, solid at room temperature: called fats -Oils: lower melting points and liquid at room temperature -Melting point is influenced by the type, form and length of fatty acids Ex. Long-chain fatty acids and saturated fats have higher melting points

Grade standards of butter

Grade AA, Grade A Butter must have at least 80% milk fat by federal law

Functions: Texture

Higher fat content in ice cream gives a smoother and creamier mouth feel Plasticity: ability of solid fat to hold its shape, but still be moldable -Butter is considered plastic at room temp, but not in the fridge -Aids in creating texture of pastries

Key properties of fat: Solubility

Insoluble in water, therefore do not mix readily with water-based food systems, greasy feel

What is the nutritional implications of a dietary fat intake?

It is associated with increased cholesterol levels and therefore a greater risk of heart disease

What is the emulsifier in egg yolk?

Lecithin

What are the essential fatty acids?

Linoleic and linolenic -human bodies don't produce these so they must be consumed

Ghee butter

Made by simmering butter until the water is cooked off and milk solids begin to brown

Cultured butter

Made from cream cultured with bacteria -Has more pronounced flavor

Sweet or clarified butter

May be clarified by melting the butter and removing the milk solid and water components

Function: Transfers heat - melting point

Melting temperatue range depending on mixture of fatty acids -longer fatty acid chains, greater the melting point

Functions: Emulsions: - Types of emulsions

Oil-in-water: droplets of oil are dispersed in water ex: milk, mayonnaise, gravies, salad dressing Water-in-oil: water is dispersed in oil ex: butter or margarine

Fat Spoilage: Rancidity

Rancidity: deterioration of fat bc by uptake of oxygen or water -Hydrolysis: compound splits in contact with water -Oxidation: oxygen replaces hydrogen -Prevent: store in a cool, dry place

Chemical structure: saturated, monounsaturated, polyunsaturated

Saturated:no double bond Monounsaturated: one double bond -MUFA: olive, canola, and peanut -PUFA: safflower, flaxseed, walnut Polyunsaturated: less than one double bond

How did the two fat substitutes compares to the margarine containing brownies in appearance, texture, and flavor?

The brownies with applesauce looked very aerated on top (lots of little holes) and it looked like it would be dry, but had a moderate chocolate flavor and were gooey and moist. The brownies with baby food prunes looking very moist and well cooked. They had a stronger flavor and you could definitely make out the prune flavor, they were also very soft and gooey.

Fat Spoilage Prevention

Store in a cool, dark place Keep tightly covered Add antioxidant: protects the fat Remove germ of grgains

Which of the fat substitutes used in lab produced the best product? Why?

The best fat substitute were the black beans in the brownies. The flavor and texture were very desirable. It was a very strong, chocolate flavor and they were most and soft.

Define the terms below and give an example of a food product Temporary vs permanent emulsion

Temporary: if oil and water are shaken together, it forms an emulsion but on standing they separate ex. French and italian dressings Permanent: can be held or stored without separation of the 2 liquids, require an emulsifying agent or stabilizer ex. mayonnaise

Functions: Emulsions - Two types of emulsifying agents

Temporary: least stable (salad dressing) Permanent: mayonnaise

Key properties of fat: Flavor

The ability of fats to take up or dissolve certain aromatic flavor substances is frequently used in food preparation Ex. butter, bacon fat, olive oil, sesame seed oil

What were the textual differences between the oil and shortening in the blueberry muffins?

The oil blueberry muffin was light on the outside in appearance and had a little bit of crunch outside but very soft and moist on the inside. The shortening muffins were more dark on the outside and had a fairly crunchy outside, the inside was soft but not as moist.

Function: Transfers heat - smoking point

The temperature at which smoke comes from the surface of the fat Will lower as a result of: -high moisture foods -suspended matter -greater surface area of fat exposed to air

Salted or unsalted butter

Unsalted in cooking offers the advantage of control seasoning of dish and more desirable when baking

Basic overview of the processing of oils

Vegetable oils are obtained from fruits, seeds, and nuts Soy and palm are the source of nearly 2/3 of the worlds vegetable oil PROCESS: oil most often is removed from oil-containing seed fruits or nuts by pressing in batches or a continuous expeller press -Hexane is the most common solvent used and is evaporated from the oil

Were there differences in flavor between the oil and shortening in the blueberry muffins?

Yes, the oil muffins only had a slightly moderate blueberry flavor, whereas the shortening muffins had a strong blueberry flavor

Emulsion of butter

about 18% water being dispirited in about 80% fat and a small amount of protein acting as the emulsifier

Market Forms: Shortening

plant oils that have been hydrolyzed to make more solid -Hydrogenation: addition of hydrogen to an unsaturated fatty acid to reduce the unsaturation and raise the melting point