The influence of intestinal proteinases on ripening of salted herring

摘要

In the present study the possible action of proteolytic enzymes was investigated by analysing enzymatic activities in fillets and brine of salted herring. The formation of low-molecular weight nitrogen compounds was larger in fillet from sugar-salted ungutted herring compared to sugar-salted gutted herring during cold storage. General proteolytic activity in brine and fillet from ungutted herring was also higher compared to gutted herring. Trypsin- and elastase-like activity were not detected in brine or fillet from ungutted herring using sensitive synthetic substrates. A weak increase in chymotrypsin-like activity was observed in brine but not in fillet from ungutted herring. Addition of bovine trypsin to brine of ungutted herring resulted in a activation of chymotrypsin-like activity and activation of elastase-like activity, indicating that these enzymes are present as inactive precursors. No activities of these enzymes were observed in fillet or brine from gutted herring.