The Taste Compounds of Fermented Squid, Loligo kobiensis

Fermented squid, Loligo kobiensis, is widely used and occupies an important position in foods of this country. But no study on its taste compounds has been reported. This study was attempted to establish the basic data for evaluating taste compounds of fermented squid. The changes of such compounds during fermentation as free amino acids, nucleotides and their related compounds, TMAO, TMA and betaine were analysed. The sample was prepared with 20% salt content and fermented at a controlled temperature of . ADP, AMP and inosine tended to degrade rapidly while hypoxanthine increased more than four times as compared with raw sample at 91 day fermentation. In the free amino acid composition of fresh squid, abundant amino acids were proline, taurine, alanine, arginine, serine, glutamic acid, lysine, glycine, leucine and valine in order. Such amino acids like phenylalanine, methionine, tyrosine, isoleucine, and histidine were poor. In squid extract, proline and taurine were dominant holding 40.2% and 32.0% of total free amino acids respectively. The total free amino acid nitrogen in fresh squid was 33.6% of its extract nitrogen. The changes of free amino acid composition in the extract of squid during fermentation was not observed. In the extract of fermented product, abundant amino acids were proline, leucine, lysine, serine, arginine, alanine, valine, isoleucine, phenylalanine, methionine and glycine in order. Glutamic acid and histidine were poor and taurine and tyrosine were trace in content. The increase of total free amino acids during 63 day fermentation reached approximately wore than 1.8 times as compared with that of raw sample and than decreased slowly. The amount of betaine increased more than 1.2 times as compared with that of raw sample during 91 day fermentation. TMA increased while TMAO decreased during fermentation. The amount of TMAO nitrogen in 91 days fermented squid was 402.4mg% on moisture and salt free base. Betaine and TMAO known as sweet compounds were abundant in fermented squid. It is supposed that these compounds could also play a role as important taste compounds of fermented squid. It is concluded that the major taste compounds of fermented squid were amino acids like proline, leucine, serine, lysine, arginine, alanine and betaine. Other compounds such as valine, isoleucine and TMAO and hypoxanthine could also not be excluded as taste supporters in fermented squid.