Heat Treatment of Haku Soy Sauce

Abstract

In order to improve the flavor of Haku soy sauce, addition of nucleic acids susceptible to be decomposed by phosphatase possibly contained in raw soy sauce was investigated.
Phosphatase activity in Haku soy sauce was completely inactivated by heat treatment at 80°C for ten minutes or at 85°C instantly.
Heat treatment did not give any significant change in the constituents, but resulted in browning to some extent, and sedimentation with some samples among the heated one.
A slight improvement was found in the smell, but not in the taste as the result of organoleptic test.