Quality Changes and Processing of Fermented Red Snow Crab Chionoecetes japonicus Sauce using Aspergillus kawachii koji

This study investigated changes in the quality of fermented red snow crab Chionoecetes japonicus sauce with or without Aspergillus kawachii koji and added salt. Samples were divided into four groups depending on whether koji was added and the amount of salt: RC15, 15% added salt, no koji; RC20, 20% added salt, no koji; RK15, 15% salt plus 10% koji; and RK20, 20% salt plus 10% koji. The samples were fermented at 20±2°C for 4 months. During the fermentation period, the moisture contents of the four types of sauce decreased while the crude ash and protein contents increased. The pH of the RK groups decreased and was lower than in the RC groups. The acidity of the RK groups increased and was higher than in the RC groups. Both the total nitrogen (TN) and amino nitrogen (AN) levels increased continuously and were higher in the RK groups than in the RC groups. The volatile basic nitrogen (VBN) content increased rapidly and was higher in the RC groups than in the RK groups. The color did not differ significantly among the four groups. The viable cell counts in the four groups increased and no coliforms were detected. The total free amino acid and glutamic acid contents were highest in the RK15 group and the main amino acids in RK15 were aspartic acid, glutamic acid, alanine, leucine, phenylalanine, and lysine. Overall acceptance was significantly higher for the RK groups than the RC groups and RK15 ranked highest among the four sauces. These results suggest that Aspergillus kawachii koji is beneficial for processing fish sauce made using red snow crab.