Application of a crude digestive proteases preparation to improve the ripening of marinated fillets from low‐technological value Baltic herring (Clupea harengus membras L.)

Abstract

BACKGROUNDDue to the climate change (reduced the oxygen content and food available in the waters) and overfishing, ever larger batches of the herring catch are classified as low‐value fish and used for feedstuff or canned food production. Fast and complete ripening of marinated fillets, especially from low‐value Baltic herring, poses a problem due to low muscle protease activity and changes in muscle tissue proteins.RESULTSFor the first time, a crude digestive proteases preparation (CDPP) was obtained from herring viscera using a two‐stage method consisting of ethanol extraction and then salt precipitation. CDPP had a reduced hemoglobin content, optimum activity at pH 7.5‐8.8 or 60‐120 g·kg‐1 NaCl. At pH 4‐5, it still exhibited 24‐68% of proteolytic activity. CDPP was used for 4‐24 h brining of fresh and frozen‐thawed fillets or injection of fresh fillets before marinating. CDPP‐brining increased especially cathepsin D and carboxypeptidase‐A activities, while decreased cathepsin B and L activities in the marinades. CDPP‐brining mitigated the negative effect of freezing‐thawing on mass‐yield, proteases activity, protein hydrolysis, texture profile, colour and sensory quality of the marinated fillets. CDPP‐injection proved to be the best method because it increased mass‐yield and ripeness of the marinated fillets to a greater extent than CDPP‐brining did. The marinades from the CDPP‐treated fillets had no bitter taste due to the presence of hemoglobin or chymotrypsin, and there were no results indicating lipid oxidation.CONCLUSIONThe application of CDPP in marinating technology proved to be a viable approach to enable using low‐value herring in food production, shorten marinating time, and improve the ripeness and sensory quality of meat.This article is protected by copyright. All rights reserved.