1. FUNCTIONS of LIPIDS
Principles of Food Science, Glencoe, Janet Ward.
Chapter 10, pages
Presentation prepared by Alice F. Mullis February 2011

2. FUNCTIONS OF LIPIDS 1. 4. ENHANCE FLAVOR TRANSFER HEAT 2. 5. TENDERIZE
LUBRICATE
Principles of Food Science, Glencoe, Janet Ward.
Chapter 10, pages 3. 6.
LIQUIDS in EMULSIONS
AERATE

3. “When You’re HOT You’re HOT” 1971 hit song by Jerry Reed
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.
Principles of Food Science, Glencoe, Janet Ward.
Chapter 10, page 226.
"When You're Hot, You're Hot" is a 1971 crossover single written and recorded by Jerry Reed. The song was his most successful on the country charts peaking at number one for five weeks.
“When You’re HOT You’re HOT” 1971 hit song by Jerry Reed

4. 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.
Principles of Food Science, Glencoe, Janet Ward.
Chapter 10, pages

5. 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.
Principles of Food Science, Glencoe, Janet Ward.
Chapter 10, pages

6. 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.
Principles of Food Science, Glencoe, Janet Ward.
Chapter 10, pages

7. 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.
Principles of Food Science, Glencoe, Janet Ward.
Chapter 10, page
The purpose of “creaming the sugar and butter” in a cake recipe is to aerate the fat. The creaming process requires a fat that is softened but not melted when beating. The reason it does not need to melted is that higher temperatures (65 to 70 degrees is ideal) the fat in the butter becomes too liquid and will not support the trapped air cells.

8. 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.
Principles of Food Science, Glencoe, Janet Ward.
Chapter 10, page
The extra volume in whipped products is due to trapped air.
Whipped products can help lower fat in the diet because you appear to be using the same amount of butter on your food but are actually using less. (spreading butter on toast or corn on the cob)

9. 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.
Principles of Food Science, Glencoe, Janet Ward.
Chapter 10, pages

10. 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.
Principles of Food Science, Glencoe, Janet Ward.
Chapter 10, page 229.

11. 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:
Principles of Food Science, Glencoe, Janet Ward.
Chapter 10, page
Whipped butter is a type of butter that has been whipped to mix in normal air or nitrogen gas. The point of whipped butter is to create something that spreads more easily, even after it has been slightly chilled. Many companies also create whipped butter as a way of increasing the volume of the substance without actually adding more butterfat. By law in the United States whipped butter has to contain at least 25% butterfat.

12. 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.
Principles of Food Science, Glencoe, Janet Ward.
Chapter 10, page 229.
Mayonnaise is a stable emulsion of oil, egg yolk and either vinegar or lemon juice, with many options for embellishment with other herbs and spices.
Mayonnaise can be made by hand with a mortar and pestle, whisk or fork, or with the aid of an electric mixer, or an electric blender. Mayonnaise is made by slowly adding oil to an egg yolk, while whisking vigorously to disperse the oil. The oil and the water in yolks form a base of the emulsion, while the lecithin from the yolks is the emulsifier that stabilizes it. Additionally, a bit of a mustard may also be added to sharpen its taste, and further stabilize the emulsion. Mustard contains small amounts of lecithin. It is a process that requires watching; if the liquid starts to separate and look like pack-ice, or curd, it simply requires starting again with an egg yolk, whisk it, slowly add the curd while whisking, and it will emulsify to be mayonnaise.

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