Endogenous Proteases in pH 7-OB Identified by LC–MS/MS
LC–MS/MS was also used to examine the endogenous proteases in pH 7-OB (Table 2), and 16 kinds of proteases were identified. Based on the LFQ intensities of all identified proteins, it was calculated that aspartic endopeptidases showed the highest relative abundance of 3.334‰, followed by tripeptidyl-peptidase 2 (0.486‰), serine carboxypeptidases (0.325%), metalloendopeptidase (0.173‰), and subtilisin-like proteases (0.134‰; serine endopeptidases). The other proteases showed extremely low relative abundances. In one previous study, it was reported that proteases in isolated sesame OBs could hydrolyze oleosins at pH 6.5 and 35 °C (Zhao et al., 2016), but no more information were available.