Analysis of Glycerides in Lard and Non-volatile Polar Components from Oxidized Lard by Reverse Phase High Performance Liquid Chromatography and Atmospheric Pressure Chemical Ionization Mass Spectrometry

The glycerides in lard, and the polar non-volatiles in oxidized lard prepared by controlled oxidation were analyzed by reverse phase high performance liquid chromatography and atmosphere pressure chemical ionization mass spectrometry(RP-HPLC-APCI-MS) after solid phase extraction(SPE). Thirty-three glycerides including seven diglycerides and twentysix triglycerides were identified from the lard, which were dominated by 1-palmitoyl-2-linoleoyl-3-oleoyl-glycerol(16.13%), 1,3-di-oleoyl-2-linoleoyl-glycerol(15.25%) 1,3-di-oleoyl-2-palmitoyl-glycerol(12.96%), and 1-oleoyl-2,3-di-linoleoylglycerol(8.05%), according to percentages of peak areas in the total ion chromatogram. Five diglycerides and twenty-two mono-hydroperoxides derived from ten triglycerides were identified from the oxidized lard, where the mono-hydroperoxides from 1-stearoyl-2-linoleoyl-3-oleoyl-glycerol(18.44%), 1-palmitoyl-2-linoleoyl-3-oleoyl-glycerol(16.03%), 1,3-di-oleoyl-2-palmitoyl-glycerol(9.42%), 1,3-di-oleoyl-2-linoleoyl-glycerol(8.71%), trioleic(7.63%) and 1-palmitoyl-2,3-linoleoylglycerol(7.53%) were predominant. These results showed that fat control oxidation was a mild oxidation process, since only the oxidized products of mono-hydroperoxides of triglycerides were found from the oxidized lard.