Study on Correlation of Dehydrogenase Activity and Volatile Basic Nitrogen on Freshness of Shellfishe

Abstract

Storage tests studying storage temperature by measuring dehydrogenase activity and volatile basic nitrogen (VBN) for Sakiaka and Shitakiri were completed.Shelled Akagai is called Sakiaka, which has its viscera removed and arranged for eating. Shitakiri is from Aoyagi with its viscera removed. Their dehydrogenase activity and volatile basic nitrogen were measured for 4days, while stored at 0°C (in ice water), 5°C, 10°C and 18°C.In the case of Sakiaka, the dehydrogenase activity decreased with higher temperature. The dehydrogenase activity of Sakiaka stored at 18°C was less than 117μg/g, the criterion level of freshness for Sakiaka after 2days. The VBN increased with higher temperature. In this storage test, VBN was not over 25mg/100g, the criterion level for the early stages of rot.In the case of Shitakiri, the changes in dehydrogenase activity and VBN were similar to those of Sakiaka, in short, a higher temperature decreased the dehydrogenase activity and increased the VBN.Dehydrogenase activity in Shitakiri stored at 18 t was less than 90μg/g, the criterion level for the freshness of Shitakiri after 2 days, and the value of Shitakiri stored at 10 t was less than 90μg/g after 3days. VBN in Shitakiri stored at 18°C was over 25mg/100g the next day, and at 10°C, it was over 25mg/100g after 2days.The decrease in dehydrogenase activity and the increase in VBN were related to the higher storage temperature. The dehydrogenase activity and VBN provided similar judgments about the freshness of shellfish.