Effects Of Linoleic Acid On Advanced Glycation End Products In Food Model Systems

In recent years, advanced glycation end products (AGEs) are found to exist in commonly consumed foods, especially in fat diet. Many clinical researches showed that food-derived AGEs were potentially hazardous to human health. But, more researches were limited to a single intermediate contribution to the final product generation. In order to explore generating process of AGEs in fat diet, unsaturated linoleic acid was looked as target in this research, combining the changes of six intermediate in glycosylation, the effect of unsaturated linoleic acid on theAGEs in food processing was investigated.Two microemulsion systems were established, one included linoleic acid (LA), D-Glccose (D-Glc) and L-lysine (L-Lys) and other included LA, D-Glc and BSA. Intermediate products including glyoxal, malondialdehyde and fructosamine were detected by UV spectrophotometry. The pentose and fluorescence AGEs were determined by the fluorescence spectrophotometry. One of the end product-carboxymethyl lysine (CML) was detected by high performance liquid chromatography (HPLC) and reactive radicals were analysed by ESR spectroscopy in different temperentrere and pH. The changing structure of BSA and carbonyl group were detected by UV spectrophotometry. The amount of thiol was detected by Ellmans colorimetry, glycosylation product crosslinking was detected by Gel electrophoresis. Then the relevance of these products was compared in order to elucidate the effect of linoleic acid on the reaction pathway.The ratio of the lysine reaction system that containing fat is:Span-800.328 g, Tween-20 2.913 g, n-butyl alcohol 1.21 mL, LA 0.25 g, D-Glc 1.48 g and L-Lys 0.36 g. This microe-mulsion system can keep clear and demulsification for 40 h in 60 ℃. When the content of water is 65%, the conductivity changing, it instructs a O/W microemulsion system.In system of LA, D-Glc and L-Lys, LA can effectively participate in the glycosylation reaction. When react for 15h, the amount of GO in lysine system containing fat over 1.5 times the non-fat one, LA can promote the generation of GO significantly. The amount of fructose-mine in non-fat lysine system over 2 times the fat one, LA can reduce the generation of fructosamine significantly. When react for 30h, the amount of fl-AGEs in non-fat lysine system over 84%containing fat one, LA can reduce the generation of fl-AGEs significantly. But the effect of LA to pentosidine CML and malondialdehyde formation is not obvious. LA can change the signal strength of free radical significantly. A large number of free radicals generating from LA oxidation is the main source.In system of LA, D-Glc and BSA, LA can promote the hydrolysis of BSA, accelerate the change of the secondary structure, and promote the generation of the carbonyl significantly. When react for 40h, in the lipoprotein system, the grayscale value of the first strips of the electrophesis photo over 75%the non-lipoprotein system, and in the non-lipoprotein system, the grayscale value of the second strips of the electrophesis photo over 73%the lipoprotein system, LA can increase the crosslinking of the glycosylation products significantly. The content of the CML in lipoprotein system over 3.55 times the non-lipoprotein one, LA can promote the generation of the CML significantly. The content of the pentosidine in the lipo-protein system over 24%the non-lipoprotein one, LA can promote the generation of the pentosidine significantly. When react for 20h, the amount of fl-AGEs in the lipoprotein system over 49.2%the non-fat one, LA can ncrease the generation of fl-AGEs. But the influence in protein hydrolysis is not obvious.We may safely draw the conclusion, LA can promote the formation of oxidation products effectively, accelerate glycosylation reaction which is because of the oxidation, alter protein structure. Thus LA can accelerate the generation of the formation of advanced glycosylation end product which from oxidation.