Impact of thermal processing on physicochemical properties of silk moth pupae (Bombyx mori) flour and in-vitro gastrointestinal proteolysis in adults and seniors

Elimination of insects' appearance by processing may increase their consumer acceptance in the western world. This study elucidates the outcomes of cooking and baking in presence and absence of fructose on silk worm pupae (Bombyx mori) flour (SWF). Elemental analyses of SWF reveal it is rich in lipids, protein and minerals like calcium. ζ-potential analyses revealed charge reversal at pH values below pH = 4. Particle size analyses showed heat-induced Maillard glycation significantly (p <.05) accentuated reduction in mean volume weighed (d4,3) diameters. In vitro gastrointestinal digestion of SWF and processed SWF showed different breakdown patterns evident in SDS-PAGE and LC-MS/MS analyses. Interestingly, baking with fructose significantly (α < 0.01) diminished the number of peptides liberated by pepsinolysis. Moreover, cooking or baking in the presence of fructose induced a reduction of bioaccessible peptides that are homologous to arthropoda phylum bioactive peptides (>70% homology), such as antimicrobial and Acyl-Co-A binding peptides. Predictive software (PeptideRanker) analysis showed a decrease in the total number of potentially novel bioactive peptides (bioactivity probability >80%) in baked SWF with fructose. Comparison of SWF and processed SWF proteolytic breakdown in adults and seniors highlighted seniors may be less apt to digest SWF products, yet, 14 potentially novel bioactive peptides were uniquely liberated in the elderly gut. Overall, this study shows process-related Maillard glycation may interfere with SWF potential to generate bioactive peptides during digestion in adults and seniors.