Why are there fats in our diets?
They provide energy, they store energy, insulation, protection, transport fat-soluble vitamins. Help satisfy hunger and make food taste good.
What are lipids?
There are three types of lipids: Triglycerides, Phospholipids, and sterols (cheolesterol). They are not ready to dissolve in water. They are a fat which is solid and oil that is liquid also are macronutrients that provide energy. 9kcal 1gm
A compound that can suspend fat in water by isolating individual fat droplets, using a shell of water molecules or substances to prevent the fat from coalescing. Example. Salad dressing- oil and water separate but when agitated (shaking the bottle) the contenants in the bottle emulsify with the fatty acid with the oil in the center surrounded by a water shell.
What is a fatty acid?
Fatty acids are found in our food (triglycerides). Saturated fatty acids are in solid form. Unsaturated fatty acids are in liquid form.
What are essential fatty acids and their functions?
- Omega-3 fatty acids (alpha-linolenic acid) an 18 carbon, 3 double bonds.
- Omega-6 fatty acids (linoleic acid)an 18 carbon, 2 double bonds- body can only make the db after the 9th carbon from the omega end
- Immune function, vision, cell membrane, and production of hormone-like compounds
What are triglycerides?
The most common forms of fats and oils. The fatty acid attaches to the glycerol.
Glyerol + 3 Fatty Acids turns to Triglycerie + 3 h2O
Where are phospholipids found, what are there functions and in what foods?
- Located- cell membranes, the body, synthesized as needed, are similar to TG's but phosphate is on 3rd glycerol carbon
- Function- Bile acid, lecithins, improves food products
- Foods- wheat germ, peanuts, yolks, soy beans, organ meat
What are sterols?
multi-ringed structure, no glycerol backbone, cholesterol is a sterols, waxy substance, found only in animal foods, and like other lipid, they do not readily dissolve in water
What is cholesterol?
It is produced by the liver, found only in animal products, essential to cell membrane, it forms important hormones: estrogen, testosterone, vitamin D and it a precursor to bile acids.
Sources of fats?
- Animal based: Butter, Lard, Tallow, Fish oil
- Plant based: Oils- seeds, olives, Products made from oils- margarine, spread, Avocado, Nuts and nut butters
What are fat substitutes?
- Water- diet margarine and spreads
- Starch derivatives- Z-trim, modified food starch
- Fiber cellulose-maltrin, stellar, oatrim
- Dairy-Lo- Protein globules
- Olestra or Olean (links FA to sucrose)- not digested, FDA approved, fat-soluble vitamin issue
Rancidity- what is it and how do you control it?
- it is decomposed oils, it is the breakdown of the C=C bonds by UV light and or O2, it has an unpleasant odor and flavor, PUFA more susceptible, it has a limited shelf life.
- control it by hydrogenation, addition of antioxidants- vitamin E, butlated hydroxyanisol (BHA) and butylated hydroxytolune(BHT), ascorbic acid, other preservatives
What is hydrogenation?
It is the process used to solidify an oil. It is the addition of an H to the C=C db that makes PUFA FA more SFA. It increases the shelf life. Helps in the formation of trans fatty acids (shape is simiar to the SFA)