Pilot-Scale Production of Sericin-Derived Oligopeptides (SDOs) from Yellow Silk Cocoons: Peptide Characterization and Specifications

Our previous research demonstrated the health benefits of sericin-derived oligopeptides (SDOs) from yellow silk cocoons, particularly their hypoglycemic and antihypertensive properties. This study aims to produce SDOs at a pilot scale, preparing them for large commercial production as a novel food ingredient, and investigates the impact of scale-up on their characteristics and specifications. We compared the productivity of SDOs generated from 25 L and 300 L batches via the hydrolysis of sericin using 5% Neutrase (E/S) at 50 °C for 4 h. The 300 L production scale outperformed the 25 L scale, achieving a hydrolysis degree (DH) of 8.63%, a solid recovery rate of 94.35%, and enhanced inhibitory actions for dipeptidyl peptidase IV (DPP-IV) and angiotensin-converting enzyme (ACE). The characterization of peptides was carried out in ultrafiltered SDOs. Peptides < 3 kDa demonstrated optimal enzyme inhibition and were then fractionated by size exclusion chromatography into nine distinct fractions. Of the nine fractions, F1, F8, and F9 had significant enzyme inhibitory activity. LC-MS/MS analysis revealed 32 unique peptide sequences, with YPDLPYH exhibiting significant dual inhibitory effects on both DPP-IV (IC₅₀ 1.35 mM) and ACE (IC₅₀ 18.10 μM). The maximum residue limit (MRL) for trace metals, pesticide residues, and microbiological contamination in SDOs complies with food regulations. SDOs exhibited stability at 4, 25, and 45 °C for six months, based on their physical characteristics and biological activity. Considering their investigated characteristics, SDOs could be manufactured at a pilot capacity and used as a functional food component in commercial applications designed to improve metabolic health.