《食品化学 Food Chemistry》课程教学课件（讲稿，英文版）Food Lipids.pdf_大学文库

Food Lipids

Lipids z “Lipids consist of a board group of compounds that are generally soluble in organic solvents but only sparingly soluble in water.” “.Glycerol esters of fatty acids, which make up 99% of the lipids of plant and animal origin have traditionally been called fats and oils” Nawar, “Lipids” Food Chemistry, Fennema Ed. 1996

Lipids are non-polar (hydrophobic) compounds, soluble in organic solvents. Fatty acids consist of a hydrocarbon chain with a carboxylic acid at one end. CH 3(CH 2 ) n-COONon-polar polar

docosanoic behenic 22:0 340.5 eicosanoic arachidic 20:0 312.5 octadecanoic stearic 18:0 284.4 margaric 17:0 270.4 (daturic) heptadecanoic hexadecanoic palmitic 16:0 256.4 tetradecanoic myristic 14:0 228.4 dodecanoic lauric 12:0 200.3 decanoic capric 10:0 172.3 nonanoic pelargonic 9:0 158.2 octanoic caprylic 8:0 144.2 hexanoic caproic 6:0 116.1 pentanoic valeric 5:0 butanoic butyric 4:0 88.1 Molecular wt. Shorthand designation Systematic name Trivial name Saturated Fatty Acids

310.5 338.6 20:1(n-9) 22:1(n-9) gondoic erucic cis-11-eicosenoic cis-13-docosenoic vaccenic 18:1(n-7) 282.4 (asclepic) cis-11-octadecenoic tr-9-octadecenoic elaidic tr18:1(n-9) 282.4 cis-9-octadecenoic oleic 18:1(n-9) 282.4 cis-9-hexadecenoic palmitoleic 16:1(n-7) 254.4 cis-9-tetradecenoic myristoleic 14:1(n-5) 226.4 Shorthand Molecular wt. designation Systematic name Trivial name Mono-Unsaturated Fatty Acids

6,9,12,15-octadecatetraenoic stearidonic 18:4(n-3) 276.4 9,12,15-octadecatrienoic α-linolenic 18:3(n-3) 278.4 4,7,10,13,16,19-docosahexaenoic DHA 22:6(n-3) 328.6 5,8,11,14,17-eicosapentaenoic EPA 20:5(n-3) 302.5 5,8,11,14-eicosatetraenoic arachidonic 20:4(n-6) 304.5 6,9,12-octadecatrienoic γ-linolenic 18:3(n-6) 278.4 9,12-octadecadienoic linoleic 18:2(n-6) 280.4 Molecular wt. Shorthand designation Systematic name Trivial name Poly-Unsaturated Fatty Acids

Lipids Storage (neutral) Membrane (polar) TAG PL GL H2C HC H2C O O O C(CH2)14CH3 C(CH2)7CH=CH(CH2)7CH3 P O O O O- O X CH HC H2C N H O C(CH2)22CH3 X O HO CH=CH(CH2)12CH3 H2C HC H2C (CH2)14CH3 (CH2)7CH=CH(CH 2)7CH3 (CH2)16CH3 OC OC OC O O O

Phospholipids z Pi is in turn esterified to OH of a polar head group (X): e.g., serine, choline, ethanolamine, glycerol, or inositol. z The 2 fatty acids tend to be non-identical. They may differ in length and/or the presence/absence of double bonds. O P O O− O H2C CH H2C R1 C O O O C O R2 X glycerophospholipid

Name of Net charge glycerophospholipid Name of X Formula of X (at pH 7) Phosphatidic acid -H -1 Phosphatidylethanolamine Ethanolamine 一CH-CH2-NH3 0 Phosphatidylcholine Choline -CHz-CH2-N(CH3)s 0 Phosphatidylserine Serine -CHzCH-NHs -1 c00 Phosphatidylglycerol Glycerol -CHzCH-CHzOH OH H O-P Phosphatidylinositol myo-Inositol 4.5- 4,5-bisphosphate bisphosphate OH HO 0-® Cardiolipin Phosphatidyl- CH 2 glycerol CHOH O H

Sphingolipids z Sphingolipids are derivatives of the lipid sphingosine, which has a long hydrocarbon tail, and a polar domain that includes an amino group. z The amino group of sphingosine can form an amide bond with a fatty acid carboxyl, to yield a ceramide. H2C H C OH CH N+ CH C CH2 CH3 H H3 OH ( )12 sphingosine H2C H C OH CH NH CH C CH2 CH3 H OH ( )12 C R O ceramide