Novel strategy for the demulsification of isolated sesame oil bodies by endogenous proteases

Abstract

AbstractThis study aimed to develop a novel method to demulsify the isolated sesame oil bodies (OB) to recover oil by directly using the endogenous proteases in the isolated OB. In this study, it was found that the isolated sesame OB contained OB intrinsic proteins as well as extrinsic proteins. The OB intrinsic proteins at least included one 41 kDa steroleosin, two 39 kDa steroleosins, two 27 kDa caleosins, four 27 kDa oil body‐associated proteins, three 17 kDa oleosins, and four 15 kDa oleosins. As for the OB extrinsic proteins, the predominant ones were 11S globulins, followed by 2S albumins and 7S globulins. In addition, the OB extrinsic proteins contained sesame endogenous proteases, predominantly including aspartic endopeptidases, subtilisin‐like proteases, serine carboxypeptidases, and metalloendopeptidase. The results revealed that the combined activity of these endogenous proteases was optimal at pH 4–5 and 50–60°C. The oleosins were the most easily hydrolyzed by these proteases, followed by 11S and 7S globulins, and the 2S albumins had strong resistance to these proteases. By incubation at pH 5 and 60°C for 2 h, approximately 97% of total lipids in isolated sesame OB (78% of total lipids in sesame seeds) could be recovered as oil by centrifugation, whereas no oil could be obtained when the incubation time was 0 h. These results indicated that the endogenous protease‐induced degradation of oleosins was the key point for the efficient demulsification of isolated sesame OB.