1

2 Notes: What are lipids?  A family of chemical compounds that are a main component in every living cell.  They are organic and have carbon chains with attached hydrogen atoms and a carboxyl group at one end. FAT CELL

3 Notes: 3 types of Lipids  1) Phospholipids-used as emulsifyers  2) Sterols-bile acids and certain hormones (found in both plants and animal foods, but cholesterol is only found in animal foods)  3) Triglycerides-largest group (fats/oils)  Chapter 16 - Text p. 239

4  1) Phospholipids: dissolve in both fat and water. Used as emulsifiers that mix fats with water products like mayonnaise. (Components of cell membranes)

5  2) Sterols: include bile acids, and certain hormones that carry out vital functions. Both plants and animals foods have sterols, but the most well known,-cholesterol is only found in animal food sources -cholesterol is used for digesting fat and making vitamin D, making some hormones, and building cells. Our bodies make all the cholesterol we need but we still get it animal foods. Cholesterol is a complex molecule its formula is: C 27 H 45 OH

6  3) Triglycerides (“fat”): the largest class of lipids which includes all of the fats and oils we typically eat.  -stored as adipose tissue: pockets of fat storing adipose cells  Figure: 16-1

7 Notes: Forms of fat  Animal sources  Butter  Lard  Eating different types of fat can have different effects on the body.  Plant sources  Margarine  Oils  Shortening

8 Notes: Fat per day  30 % of your calorie intake or less intake or less Fat= 9 calorie per gram (sugar was 4 calories per gram)

9  Women 19-49yrs 65 gms 16 tsp  Men gms 22 tsp  gms 15  1 tsp = 4-5 g fat

10 Notes: What is a Carboxyl group -COOH ?

11 Notes: Structure of Triglycerides  Fats are made from glycerol and fatty acids.  Each glycerol is attached to 3 fatty acids.  They contain carbon, hydrogen and oxygen

12 triglyceride

13 Notes: Fatty Acids  These are the organic acids in triglycerides  They have a carbon chain with attached hydrogen atoms and a carboxyl group (-COOH) at one end. (Figure 16-2)  The simplest fatty acid has a two carbon chain (acetic acid p. 241 fig. 16-3)  3 react with glycerol to from a “triglyceride” (Figure 16-4 p. 241)

14 Notes: Essential Fatty Acids (EFA’s)  Are those the body must get through food as we cannot make them.  They are linoleic and linolenic fatty acids  Are needed for normal growth and development.  Found in: veggies, grains, nuts, seeds, and soybeans

15 Notes: Fatty Acids and Bonding  FA’s carbon atoms are joined in covalent bonds that are either single bonds or double bonds.  These bonds help to distinguish between saturated and unsaturated fats.  Text p , figure 16-5

16 Notes: Saturated fats  Animal sources  Fatty acids are saturated-hold all the hydrogen atoms they can.  Solid at room temperature  We make our own.

17 Sources  Animal products

18 Notes: Unsaturated fats  Missing hydrogen bonds so single bonds cannot form, instead, a double bond forms  2 carbon atoms missing a hydrogen bond join together  Can be monounsaturated or polyunsaturated.  Liquids at room temperature  Question: Is their a mistake in this diagram?

19 Again Mistakes in diagram?  Monounsaturated - lacks 2 hydrogen- has one double bond  Polyunsaturated- lacks more than 2 hydrogen- 2 or more double bonds

20 MOnounsaturatedMOnounsaturated monounsaturated Saturated

21 Notes: Cis vs. Trans Fatty Acids  Unsaturated fatty acids are “kinked” at the double bonds between carbon atoms.  If the hydrogen atoms are missing from the same side of the double bonded carbon atoms this is called the cis configuration.  If the hydrogen atoms are missing from opposite sides of the double bonded carbon atoms this is called the trans configuration.

22 Notes: Properties of triglycerides  9 calories per gram  Only slightly soluble in water  The have phase differences (liquid vs. solid)  Fats melt at different temperatures  Solidification point- temperature at which a melted fat regains its original firmness.

23 Notes: Fats in Food  Provide essential fatty acids  Transport fat soluble Vitamins A D E K  Sensory appeal  Tenderize  Aeration  Influence emulsions  Add flavour  Rancid as fats oxidize

24 Make foods taste better

25 Notes: Commercial use and cooking with fats  Commercially: (2 groups) A) animal fatsB) plant oils A) animal fatsB) plant oils  Plant oils undergo hydrogenation a process that adds hydrogen to unsaturated fat breaking some double bonds replacing them with single ones. Example: Vegetable shortening (solid)

26 Hydrogenated Vegetable oil  The process of adding hydrogen to unsaturated fatty acids  Good- Makes them resistant to oxidation- go rancid more slowly  Good- makes them more stable  Bad- makes them more saturated

27 Notes: Trans fatty acids  Occur when hydrogenation is done the unsaturated fats become saturated  Hardened margarines

28 Smoking point  The point at which a fat begins to give off smoke when heated.  High- peanut, canola  Low- butter

29 Olestra- artificial fat  Remains undigested  Passes through the digestive tract intact  Had too many bad side effects

30 Notes: Use of fats in the body  1. Energy  2. Fat storage – for later use  3. Shock absorbers for the vital organs  4. Satiety value – makes us feel full longer  5. fats are converted to other compounds- hormones, bile, Vitamin D

31 6. Insulates – a fat blanket under the skin

32 Notes:Cholesterol  Used to make bile  Causes build up of plaque in the arteries  Found in animal sources  Cause cardiovascular disease  2 types: LDL and HDL (travel in lipoproteins) (travel in lipoproteins) Figure 16-9 Figure 16-9

33 LDL cholesterol [ bad]  Carries cholesterol to to the body tissues to deposit there  When elevated forecast heart and artery disease  Oxidation of LDL causes damage to arteries

34 HDL cholesterol [good]  HDL cholesterol- carries cholesterol away from tissue

35 Antioxidants  Slows oxidation of LDL  Vitamin C, Vitamin E, selenium are antioxidants

36 Why exercise?  Develops higher HDL  Circulation improves  Larger volume of blood pumped each heart beat, reducing heart’s workload  Overall leaner body- reducing risk

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38 Omega-6 Fatty acids  Omega-6 fatty acids belong to a group of "good" fats called polyunsaturated fatty acids.  Help with immune system  Relax Good dietary sources of omega-3 fatty acids

39 Sources of fat in average diet  Fresh meat = 8.5 %  Processed meat = 11%  Poultry =2.5  Meat alternatives =7%  Milk =6%  Milk products = 18%  Veg and Fruit =2%  Baked goods=9.5%  Fats and oils=31%