Unit: LIPIDS Oxidation and Trans Fats

Warm-Up - Answer In your notebooks: 1.What are the 3 classes of lipids in the body? 2.Name 2 reasons we need fats in the body:

Answers: 1. What are the 3 classes of lipid in the body? ○ Triglycerides (95% of all lipids in the body) ○ Phospholipids (includes Lecithin) ○ Sterols (includes Cholesterol 2. Name 2 reasons we need fats in the body: ○ Energy stores ○ Muscle fuel ○ Emergency reserve ○ Padding ○ Insulation ○ Cell membranes ○ Raw materials

Objectives Today we will… ○ Describe ways lipid oxidation can be controlled in food. ○ Examine trans fats. ○ Activity- Track the Trans Fats

Oxidation ○ What is Oxidation? ○ The interaction of a compound with oxygen. ○ Where can it occur in fatty acids? ○ At the unsaturated points in the fatty acids. ○ What happens when oxidation occurs in foods made with oil? ○ Oxidation makes food become rancid and taste “off” ○ Can oxidation be prevented? ○ Yes! With proper food storage.

Stopping oxidation in foods ○ KEEP OUT OXYGEN! ○ Cooking oils should be stored in air tight containers or refrigerated. ○ Addition of preservatives. ○ Hydrogenation of unsaturated fats. ○ Points of unsaturation are weak and vulnerable to attack by oxygen.. ○ How to prevent oxidation of avocados video: Click image

Chemical Preservatives ○ An alternative to hydrogenation is to add chemical preservatives that will compete for oxygen and protect the oil. ○ These additives are called antioxidants – they react with oxygen before it can do damage.

Hydrogenation ○ Hydrogenation is… ○ The process of adding hydrogen to unsaturated fatty acids to make fat more solid and resistant to the chemical change of oxidation. ○ The hydrogenation of a fat makes it stay fresher longer and also changes the physical appearance. ○ Video: Hydrogenation of margarine… Click image

The downside of hydrogenation ○ Yes…hydrogenation makes oils harder, smoother, have a higher smoking point, and resist oxidation but…. The downside of hydrogenation is that: ○ Hydrogenated oils lose their unsaturated characteristics and health benefits. ○ It not only affects the oil but also vitamins such as vitamin K, by decreasing their activity in the body.

Ahhhh!!!! Trans Fats ○ Trans fatty acids – fatty acids with unusual shapes that can arise when hydrogens are added to the unsaturated fatty acids of polyunsaturated oils (hydrogenation) ○ During hydrogenation some of the UFA end up changing shape instead of becoming saturated. OOPS! ○ This change in shape changes their effect on health. ○ Eating trans fats raises LDL and lowers HDL. It may also increase inflammation HEART DISEASE. Cis Trans

Where are trans fats found? ○ In the US, most are from commercially fried foods: donuts, fried chicken, baked goods, chips, cookies, crackers, cakes, frosting and other commercially prepared or packaged foods. ○ Some trans fats occur in small amounts naturally, mostly in dairy products. ○ How to spot trans fats video: Click image

Activity #1 ○ Butter Alternatives Taste Test ○ Please clear your tables and wait for instructions.

Activity #2- Track the Trans Fats ○ Compare each food label and indicate how many grams of grams of trans fat each contain, if they contain hydrogenated oils, and determine which is the better food choice. ○ Turn in to the Mrs. Scherr’s basket when complete. Do for homework if unable to finish and turn in next time.

What have learned today? ○ We describe ways lipid oxidation can be controlled in food. ○ Keeping out oxygen ○ Chemical preservatives ○ hydrogenation ○ Examine trans fats. ○ What they are and how they effect our health ○ How to spot trans fats on food labels.