FUNCTIONS of LIPIDS FUNCTIONS of LIPIDS Presentation prepared by Alice F. Mullis February 2011

FUNCTIONS OF LIPIDS TRANSFER HEAT TENDERIZE AERATE ENHANCE FLAVOR LUBRICATE LIQUIDS in EMULSIONS

LIPIDS TRANSFER HEAT Fats are an excellent heat medium. Transfer heat from cooking utensils to food quickly, evenly and at very high temperatures. Temperature will continue to increase as heat is added; heat cannot be added indefinitely. “When You’re HOT You’re HOT” 1971 hit song by Jerry Reed

LIPIDS & SMOKING POINT Every lipid has a temperature point when the fatty acids begin to break apart and produce smoke…..called the “smoking point”. Fatty acids combine with oxygen and form new compounds that have strong and unpleasant odors. Once the oil begins to smoke, breakdown has occurred and the oil should be discarded.

LIPIDS & FLASH POINT The flash point is the temperature at which lipids will burn and form a flame. Heated oil should be monitored at all times or a grease fire may occur.

LIPIDS as Tenderizers Fats are used to tenderize baked products. Fat shortens long strands of protein in flour used in baked goods. (“shortening”) Solid fats coat flour particles, making the dough slippery thus preventing long strands from forming.

LIPIDS as AERATERS Aeration is the addition of air into a batter. Saturated fats allow tiny air pockets to form when batters are sufficiently beaten. Often cake recipe directions call for fat and sugar to be “creamed” together.

LIPIDS as AERATERS Whipped margarines and butter products are made more spreadable by adding air. Unwhipped butter or margarine is packaged with 4 sticks per container. Whipped butter or margarine is packaged with 6 sticks per container. Extra volume in whipped product is due to trapped air.

LIPIDS as AERATERS 1 stick of whipped butter is not the same as 1 stick of butter. Whipped butter would not make a good substitute for butter in a recipe because its proportions are not the same.

ENHANCE FLAVORS Lipids provide a lot of flavor to food: - Spreading butter on bread - Bacon Fat added to vegetables - Cook onions, garlic, celery, peppers in fat as first step in food preparation Lipids dissolve and disperse flavor compounds in foods such as vegetables or salad dressings. Exception to the rule – Cottonseed Oil is used to make potato chips because it is most flavorless of the oils.

LIPIDS as LUBRICANTS Marbling makes meat easier to chew (small flecks of fat distributed throughout meat). Greasy texture gives a slick feel to mouth and tongue causing food to seem moister. Butter, margarine and mayonnaise are popular spreads for breads and rolls; make foods seem moist and not soggy. Frequently asked questions about butter:

LIPIDS & EMULSIONS Lipids are usually one of the two liquids in an emulsion (a mixture that contains a lipid and a water- based liquid). Examples are mayonnaise, butter, milk and bottled salad dressings.

RESOURCES Principles of Food Science, Glencoe, Janet Ward. Chapter 10, pages