COMPARATIVE ANTIOXIDANT ACTIVITY OF MAILLARD-DAMAGED AND OXIDIZED LIPID-DAMAGED BOVINE SERUM-ALBUMIN

The antioxidative activity of nonenzymatically browned proteins produc ed by reaction with both carbohydrates and oxidized lipids was studied to compare the effect of formation of Maillard reaction products (MRP ) and oxidized lipid/amino acid reaction products (OLAARP) in the stab ilities of foods during processing and storage. Bovine serum albumin ( BSA) was incubated at 80 degrees C for 24 h in the absence (control, C O) or in the presence of 10 mM glucose (GL), fructose (FR), ribose (RI ), methyl linoleate hydroperoxides (KP), and secondary products produc ed in the oxidation of methyl linoleate (SP). The modified proteins (C OBSA, GLBSA, FRBSA, RIBSA, HPBSA, and SPBSB) were isolated, characteri zed by amino acid analysis, and tested for antioxidative activity (at 100 ppm) in soybean oil using the thiobarbituric acid-reactive substan ces (TEARS) assay. All of them significantly (p<0.05) decreased TEARS formation and exhibited the following order of effectiveness: COBSA < GLBSA < FRBSA approximate to HPBSA < SPBSA < RIBSA < BHT. No big diffe rences among antioxidative properties of OLAARP- and MRP-containing pr oteins were observed under the assayed conditions. Therefore, both Mai llard and oxidized lipid/protein reactions may be contributing analogo usly to increase the stability of foods during processing and storage.