Protein–peptide nutritional material prepared from surimi wash‐water using immobilized chymotrypsin–trypsin

Background: In the production process of surimi, large quantities of wastewater are produced. Thus it would be interesting to develop an efficient protocol for the recovery of protein from hairtail surimi wash-water.; Results: A technique involving the use of immobilized chymotrypsin-trypsin (I-CT) was developed, providing a practical method for the preparation of protein-peptide nutritional material (PPNM). Under optimized reaction conditions, the recovery rate of nitrogen of surimi wash-water was measured as 98.3 ± 2.9%. Nutritional evaluation of the protein-peptide fraction demonstrated that it contained all essential amino acids (EAA) for humans, accounting for 44.1% of the total amino acid (TAA) content, which was determined to be 78.2 g per 100 g dry matter. The essential amino acid index (EAAI) and biological value (BV) were 101.7 (>95) and 76.7 respectively. A wide range of volatile flavor compounds (>50), including aldehydes, ketones, alcohols, hydrocarbons and heterocyclic compounds, were identified in PPNM by gas chromatography/mass spectrometry (GC/MS) analysis.; Conclusion: An efficient and practical protocol for the recovery of protein from hairtail surimi wash-water has been developed. The PPNM prepared in this work could be used as a nutraceutical and as an ingredient of functional foods. © 2016 Society of Chemical Industry.; © 2016 Society of Chemical Industry.