Fats and Oils n Structure u u Triglyceride

Fats and Oils n Structure u u Triglyceride— 3 fatty acids attached to a glycerol backbone Various fatty acids within the TG

Fats and Oils n Types Solid fats t Straight chain fatty acids t Saturated or trans fatty acids t Fat crystals suspended in oil u Liquid fats (oils) t Contain kinked chain fatty acids t Mono- or polyunsaturated fatty acids t No fat crystals u

Fats and Oils n Melting temperature is directly proportional to degree of saturation u u saturation (less double bonds) = higher melting point saturation (more double bonds) = lower melting point

Fats and Oils n Essential fatty acids Linolenic and Linoleic acids u Excellent source of vitamin E t Combats rancidity (free radical scavenger) t Varies in amounts by: • Type of plant used for pressing • Refining process t Preserved by storing in cool, dark place t Degraded by overheating u

Fats and Oils n Influences on texture (mouth-feel) and flavor Types of fatty acids present and their corresponding chain lengths u Degree of saturation (thus melting temp. ) u Degree of refinement (flavor components removed) u

Fats and Oils n Smokepoint Involves chemical degradation of glycerol molecule u Induced by overheating u Breaks down into acrolein t Irritating to eyes and nose u

Fats and Oils n Reduction of smoke point by avoiding: u Prolonged or repeated heating of fat u Collected food particles u Exposure of fat to air t Oxidation occurs t Deep fryers are better than shallow pans u Presence of emulsifiers in fats u Use of iron and/or copper pans which contributes to oxidative rancidity

Fats and Oils n Shelf life of fat can be extended: Frying below smokepoint u Cooling quickly u n Fat absorption leads to greasy products: u Oil is not hot enough (too far below smokepoint) u Cold foods u Too much food added at once

Fats and Oils n Ingredients that increase fat absorption of food Sugar u Leavening u Aqueous liquid u Fat u n Crispiness (favorable attribute) Dehydrating outer portion of food u Exchanging fat for lost moisture u

Fats and Oils n n Fat in cheese u Butterfat u Highly saturated Types of cheese and relative fat content u Dessert cheese (comparable to butter fat) u Hard cheese (1/3 fat by weight) u Low fat cheese (about 7% fat by weight) t Fat replacers • Water • Vegetable gums

Fats and Oils n Other types u u Cheese spread (Velveeta, which uses emulsifier to aid in ease of melting) Cream cheese (soft cheese) t More water than cheddar t Fat free cream cheese utilizes: