揮発性塩基,トリメチルアミン, ATP関連化合物の魚類鮮度判定法としての測定意義

抄録

Among the various tests for elucidating the freshness of fish, measurements of volatile base and trimethylamine nitrogen in the muscle have been used widely by many investigators. However, little information is available on the relation between the value of these bases and the freshness evaluated commercially by organoleptic tests. Typical uncooked Japanese seafoods, “Sashimi”, or sliced raw fish, and “Sushi” condiments were prepared from fish which were selected with the traditional severe scrutiny for flavor. Using these samples obtained from local markets, and fish killed immediately after being caught, the significance in measuring volatile base, trimethylamine nitrogen, and nucleotides and related compounds for estimating the freshness was studied. The results obtained are shown in Tables 1-6 and Figs. 1-2, and the main features are as follows:
1) The distribution of value of volatile base and trimethylamine nitrogen, far from showing linear correlation among the fish killed immediately after being caught, “Sashimi” and “Sushi” condiments of several grades of qualities, appeared to be nearly random, and no trend can be discerned. In measuring the amounts of these bases, we were only able to estimate the limit of acceptability or the onset of spoilage of the foods.
2) From the results of statistical examinations, the nucleotides decomposition ratio, Kvalue was found to be a useful index for “Ikino yosa”, or freshness in the true sense of the word, which was used as a sensory criterion in the commercial purchases and sales of fish.