CHAPTER 23 LIPIDS 23.1 INTRODCTION Lipids are compounds of biological origin that dissolve in pl nonopoler solvents Lipids are defined by the physical operation that we use to isolate them
CHAPTER 23 LIPIDS 23.1 INTRODCTION Lipids are compounds of biological origin that dissolve in nonopoler solvents. Lipids are defined by the physical operation that we use to isolate them
Lipids include a variety of structure types, For example H2C-O-C-R CH3 CH2OH HC-O-C-R O CH3 HC-0-C-R CH(CH3h A fat or oil Menthol Vitamin a (油或脂) (薄荷醇) (维生素A) H,C-0-C-R HRCI H HC-0-C—R CH, H H2C-O-P-OCH2CH2N+ CH3)3 lecithin Cholesterol (卵磷脂) (胆固醇
Lipids include a variety of structure types, For example H2C HC H2C O C R O C R' O C R'' O O O CH3 OH CH(CH3 ) 2 CH2OH CH3 CH3 CH3 CH3 A fat or oil (油或脂） Menthol (薄荷醇) Vitamin A (维生素 A） H2 C HC H2 C O C R O C R' O P OCH2 CH2N+( CH3 ) 3 O O O O - H H H 3 C H3 C H H H HO CH3 Cholesterol (胆固醇) lecithin (卵磷脂)
23.2 FATTYACIDS AND TRIACYLGLYCEROLS Triacylglycerols are the fats and oils of plant or animal origin. Oils: Triacylglycerols that are liquids at room temperature Fats: Triacylglycerols that are solids at room temperature Same triacylglycerols: all three acyl groups in triacylglycerols are the same mixed triacylglycerols: the acyl groups in triacylglycerols are different Hydrolysis of a fat or oil produced a mixture of fatty acias
23.2 FATTY ACIDS AND TRIACYLGLYCEROLS Triacylglycerols are the fats and oils of plant or animal origin. Oils: Triacylglycerols that are liquids at room temperature. Fats: Triacylglycerols that are solids at room temperature. Same triacylglycerols: all three acyl groups in triacylglycerols are the same. mixed triacylglycerols: the acyl groups in triacylglycerols are different. Hydrolysis of a fat or oil produced a mixture of fatty acids
H2C=O-C一R HOC-OH RCOOH HC-0-C-R' (1)OH/H,O, heat HC-OH RCOOH (2)H3O H2C-O-C-R H2C-OH RCOOH A fat or oil Glycerol Fatty acids (油或脂) (丙三醇) (脂肪酸) Most of fatty acids have unbrached chains and they have an even number of carbon atoms The double bonds in unsaturated fatty acids are all cis and not conjugated. Many naturally occurring fatty acids contain two or three double bonds. Triple bond rarely occur in fatty acids Saturated fatty acids have relatively high points and unsaturated fatty acids have relatively low points
H2 C HC H2 C O C R O C R' O C R'' O O O A fat or oil (油或脂） H2 C HC H2 C OH OH OH + RCOOH R'COOH R''COOH (1) OH- / H2 O, heat (2) H3O + Glycerol ( 丙三醇) Fatty acids (脂肪酸） Most of fatty acids have unbrached chains and they have an even number of carbon atoms. The double bonds in unsaturated fatty acids are all cis and not conjugated. Many naturally occurring fatty acids contain two or three double bonds. Triple bond rarely occur in fatty acids. Saturated fatty acids have relatively high points and unsaturated fatty acids have relatively low points
Triacylglycerols made up of large saturated fatty acids have high melting points and are solid in room temperature, vice versa 23.2A HYDROGENATION OF TRIACYLGLYCEROLS Solid commercial cooking fats are manufactured by partial hydrogenation of vegetable oils. Completed hydrogenation of the oil is very hard and brittle One commercial advantage of partial hydrogenation is to give the fat a longer shelf-life 23.2B BIOLOGICAL FUNCTION OF TRIACYLGLYCEROLS The primary function of triacylglycerols in animal is as an energy reserve
Triacylglycerols made up of large saturated fatty acids have high melting points and are solid in room temperature, vice versa. 23.2A HYDROGENATION OF TRIACYLGLYCEROLS Solid commercial cooking fats are manufactured by partial hydrogenation of vegetable oils. Completed hydrogenation of the oil is very hard and brittle. One commercial advantage of partial hydrogenation is to give the fat a longer shelf-life. 23.2B BIOLOGICAL FUNCTION OF TRIACYLGLYCEROLS The primary function of triacylglycerols in animal is as an energy reserve