Changes in taste substances during fermentation of fish sauce and the correlation with protease activity

Abstract

Anchovy sauce shows different taste profiles under different fermentation time. The change rules of free amino acids was measured by amino acid analyzer, and other taste substances, such as nucleotides and organic acids in anchovy sauce under different fermentation time were also investigated. Moreover, the correlation between protease activity and taste substances in anchovy sauce fermentation was analyzed by orthogonal partial least squares. Throughout the fermentation process, the taste substances in anchovy sauce increased during early months and then decreased as time increased. The content of amino acid nitrogen, TCA-soluble peptides, 5′-nucleotides (AMP, GMP, IMP) and organic acids (lactic acid, succinic acid) in anchovy sauce increased by 26%, 33%, (45%, 35%, 68%) and (27%, 2%) respectively in comparison with 6 months fermentation. Total amino acid content reached its maximum after 18 months fermentation. Results of electronic tongue demonstrated that the umami of anchovy sauce after 12 months fermentation increased by 17% in comparison with 6 months fermentation. A model correlating changes in protease activity with taste formation suggested that protease activity impacted the content of Ala, Glu, Lys, Asp, Leu, TCA-soluble peptides and succinic acid. This study can provide empirical evidence to guide the efficient processing of anchovy sauce.