The Lipids: Triglycerides, Phospholipids, and Sterols I. The Ch emi st’ s Vie w of Fat ty Ac ids a nd Tr igl ycer ide s The class of nutrients known as lipids includes triglycerides (fats and oils ), hosholiids, and sterols. !ost are triglycerides with glycerol "ack"ones and three fatty acids attached. Fatty acids #ary in car"on chain lengths, degree of unsaturation, and num"er of dou"le "onds. $aturation affects the hysical characteristics of the fat and its storage roerties. Trans%fatty acids, which are altered, ha#e the same negati#e health effects as saturated fatty acids. A. Fatty Acids &. The 'ength of th e Ca r"on Chain a. 'ong%ch ain fa tty aci ds are f ound ri mari ly in mea t, fis h, and #eg eta"le oils. ". !edium% and short%chain fatty acids are found in dairy roducts. . The egre e of *nsat ur at ion a. Saturated fatty acids carry the ma+imum ossi"le num"er of hydrogen atoms. hen most of the fatty acids are saturated it is called a saturated fat. ". Unsaturated fatty acids lack hydrogen atoms and ha#e at least one dou"le "ond. The dou"le "ond is considered the point of unsaturation . &. Monounsaturated fatty acids lack two hydrogen atoms and ha#e one dou"le "ond. hen most of the fatty acids are monounsaturated it is called a monounsaturated fat . . Polyunsaturated fatty acids (PUFA) lack four or more hydrogen atoms and ha#e at least two or more dou"le "onds. hen most of the fatty acids are olyunsaturated it is called a polyunsaturated fat . a. Linoleic acid is an essential fatty acid. ". Linolenic acid isan essential fatty acid. -. The 'ocati on of ou"l e onds a. The omega num"er refers to the osition of the first dou"le "ond. ". An omega! fatty acid has the location of the dou"le "ond in the third osition. An e+amle is linolenic acid. c. An omega" fatty acid has the location of the dou"le "ond in the si+th osition. An e+amle is linoleic acid. . Triglycerides are liids with three fatty acids attached to a glycerol . C. egree of *nsaturation /e#isited &0e T/A 12 &. Firmness a. $at ura ted f ats are soli d at room te me rat ure. ". 3olyunsaturated fats are li4uid at room temerature. c. $horte r fatt y acid ch ains ar e soft er at ro om temerat ure than l onger chains. . $t a"ility a. $atura ted fat is mor e re sis tant t o o#idation.
