loading page

Novel strategy for the demulsification of isolated sesame oil bodies by endogenous proteases
  • Yeming Chen,
  • Huina Li
Yeming Chen
Author Profile

Abstract

Oleosins are mandatory to avoid coalescence of oil bodies (OBs), so commercial proteases are used to efficiently demulsify OBs into food oil. However, the commercial proteases and pH regulators (acid and alkali) greatly restrict this method in industry. In this study, aspartic endopeptidases, subtilisin-like proteases, metalloendopeptidase, and serine carboxypeptidases were identified in isolated sesame OBs by liquid chromatography tandem mass spectrometry (LC–MS/MS). Tricine–sodium dodecyl sulfate–polyacrylamide gel electrophoresis and protease inhibitor assay revealed that aspartic endopeptidases exerted high activity against oleosins in a pH range of 3−6 and a temperature range of 40−70 °C, while subtilisin-like proteases exhibited sharp optimum at pH 5. Metalloendopeptidase contributed to the low activity against oleosins at pH 7−9. Trichloroacetic acid–nitrogen soluble index and free amino acid analyses quantitatively revealed that the activity of serine carboxypeptidases was high at pH 3−5, and optimal at pH 4; the combined activity of aspartic endopeptidases and subtilisin-like proteases was optimal at pH 5. By incubating the isolated sesame OBs at pH 5 and 60 °C for 2 h, approximately 97% of total lipids were recovered as free oil. At last, LC−MS/MS analysis gave deep insight into the intrinsic proteins of sesame OBs: three kinds of oleosins with molecular weights around 17 kDa, and four kinds around 15 kDa; besides 27 kDa caleosin, four kinds of oil body-associated proteins and one kind of peroxygenase-like protein also around 27 kDa; in addition to 39 kDa steroleosin, 11-beta-hydroxysteroid dehydrogenase-like 6 also around 39 kDa.
03 Mar 2021Submitted to Journal of the American Oil Chemists' Society
03 Mar 2021Submission Checks Completed
03 Mar 2021Assigned to Editor
26 Mar 2021Reviewer(s) Assigned
09 May 2021Review(s) Completed, Editorial Evaluation Pending
09 May 2021Editorial Decision: Revise Major
24 Jun 20211st Revision Received
24 Jun 2021Assigned to Editor
24 Jun 2021Submission Checks Completed
25 Jun 2021Reviewer(s) Assigned
30 Jun 2021Review(s) Completed, Editorial Evaluation Pending
30 Jul 2021Editorial Decision: Revise Minor
01 Aug 20212nd Revision Received
01 Aug 2021Submission Checks Completed
01 Aug 2021Assigned to Editor
04 Aug 2021Review(s) Completed, Editorial Evaluation Pending
04 Aug 2021Editorial Decision: Revise Minor
07 Aug 20213rd Revision Received
09 Aug 2021Assigned to Editor
09 Aug 2021Submission Checks Completed
10 Aug 2021Editorial Decision: Accept
26 Aug 2021Published in Journal of the American Oil Chemists' Society. 10.1002/aocs.12531