1. Chapter 10 Notes Lipids
Lipids are organic compounds that are insoluble in water and have a greasy feel
There are three types of lipids in foods and the human body
1. Glycerides
2. Phospholipids
3. Sterols

2. Lipids
Lipids have two main parts, a glycerol molecule and a fatty acid
Glycerol has three hydroxyl groups that easily react with other compounds
Fatty acids are organic molecules that have a carbon chain with a carboxyl group at one end
All organic acids have a carboxyl group- COOH

3. Glycerides Glycerides are molecules that have a glycerol base
Monoglyceride- has one fatty acid attached at a hydroxyl group
Diglyceride- has two fatty acids attached at a hydroxyl group
Triglyceride- has three fatty acids attached at a hydroxyl group, contribute flavor, satiety, and tenderness to food

4. Glycerides
Essential Fatty Acids- These are fatty acids that are not produced by the body
Linoleic acid and linolenic acid are the only two essential fatty acids
They are found in most plant and fish oils

5. Phospholipids
Phospholipid- A glycerol base with two fatty acids and a phosphorus-containing acid attached.
The fatty acids are soluble in fats while the phosphorus-containing acid is soluble in water
They help keep foods like mayonnaise from separating

6. Sterols Sterols- complicated molecules derived or made from lipids
Examples include cholesterol, vitamin D, steriods

7. Saturated vs. Unsaturated Fats
Saturated- When fatty acids have the maximum number of hydrogen atoms
This means that there are no double bonds in the carbon chain structure
Unsaturated- When a fatty acid does not contain all the hydrogen atoms it could contain
This means that there is at least one double bond in the carbon chain

8. Saturated Fats
Examples- butyric acid in butter, stearic acid in beef fat, coconut oil, palm kernel oil, palm oil

9. Unsaturated Fats
Monounsaturated- Fatty acids that have one double bond in the carbon chain
Examples- olive oil, almonds, walnuts, canola oil, margarine
Polyunsaturated- Fatty acids that have two or more double bonds in the carbon chain
Examples- Safflower oil, sunflower oil, corn oil

10. Melting Point and Solidification Point of Fat
Melting Point- The temperature at which a lipid is completely liquid
Solidification Point- The temperature at which all lipids in a mixture are in a solid state (they have regained their original firmness)

11. Fats vs. Oils
Lipids that are solid at room temperature are called fats
Fats at room temperature are usually saturated
Lipids that are liquid at room temperature are called oils
Oils at room temperature are usually unsaturated

12. Hydrogenation
The process of adding hydrogen atoms to an unsaturated lipid to increase its saturation level
This process is used at a commercial level to make some oils into a solid (shortening) at room temperature
An example of a product made from hydrogenation is vegetable shortening

13. Rancidity
Rancidity is a form of food spoilage that causes unpleasant flavor and color changes in fats and results from the oxidation of fats
Unsaturated oils are more susceptible than saturated fats because their double bonds are weaker than single bonds
Antioxidants help prevent rancidity by reacting with oxygen before the lipids do

15. Functions of Lipids in the Body
1. Lipids are a concentrated source of energy and provide 9 Calories per gram
2. Cell production- Cell walls are made from lipids and proteins. Fatty tissue is deposited around vital organs to help protect them from injury
3.Temperature regulation- Lipids act as insulators and hold in body warmth
4. Transport of vitamins- vitamins that are fat-soluble need to combine with fat to be transported throughout the body