CHANGES IN THE COMPOSITION OF FREE AMINO-ACIDS, ORGANIC-ACIDS AND LIPIDS DURING PROCESSING AND RIPENING OF HATAHATA-ZUSHI, A FERMENTED FISH PRODUCT OF SANDFISH (ARCTOSCOPUS-JAPONICUS) AND BOILED RICE

The changes in the compositions of certain chemical components during the processing of 'Hatahata-zushi', a Japanese fermented product of sandfish and boiled rice, were investigated. The pH, moisture and salt contents of the finished product were 4.1, 552 g kg(-1) and 41.0 g kg(-1), respectively on a salt-free dry weight basis. The concentrations of polyamines except histamine increased gradually during fermentation. The contents of free amino acid, especially glutamic acid, alanine, valine and leucine, increased during fermentation. Lactic acid and acetic acid contents increased markedly during fermentation. Total lipid content of the raw sample was relatively high, 385 g kg(-1) on a dry weight basis. During soaking in water, the contents of phosphatidylethanolamine (PE) and phosphatidylcholine (PC) markedly decreased, while that of free fatty acid increased. The decreases in PE and PC continued up to the end of fermentation. The triglyceride content decreased to a large extent during the early stage of fermentation period and thereafter remained almost unchanged. Lipid deterioration of 'Hatahata-zushi' seemed to be due mainly to hydrolysis of lipids by endogeneous and/or exogenous lipolytic enzyme systems.