Abstract
The chemical properties of fish sauces (n=66) collected from Thailand, Vietnam and Japan were determined. As results, the salt content, pH, for mol nitrogen content, free amino acid content and total nitrogen content ranges of these sauces were 14-28%, 5-8, 0.23-4. 22g/100ml, 1.75-22. 51 g/100ml and 1-6g/100ml, respectively. These ranges were wide compared with previous reports. In addition, fish sauces with a high total nitrogen content had a high peptide nitrogen content. Note that peptides are related to body function. The average of peptides in all the fish sauces was 32% of total nitrogen content. The Thai and Vietnamese sauces showed higher peptide nitrogen contents than the Japanese sauces. Note that fish sauces in Thailand and Vietnam, which are in the subtropical zone from the tropical zone, are ripened at higher temperatures than those in Japan, which is in the temperate zone. Therefore, it was presumed that the decomposition of fish meat protein by protease was faster in Thailand and Vietnam than in Japan. Moreover, the glutamic acid contents at 12% on average were higher than the total free amino acid contents. However, there were some samples with glutamic acid contents of 20-30%, which were higher than the glutamic acid content of fish meat protein. These samples were considered to have been supplemented with glutamic acid.
