tailieunhanh - Báo cáo nghiên cứu khoa học: " CHARACTERIZATION OF PROTEASE FROM ASPERGILLUS ORYZAE SURFACE CULTURE AND APPLICATION IN FISH SAUCE PROCESSING"

Ions Na+, Zn2+ and Fe3+ had an inhibitor effect to the enzyme activity. On the contrary, ion Mg 2+ had an activator effect. The influence of ion Ca2+ to the protease activity was more complicated. With low concentration (), this ion activated the protease; but with higher concentration (), it inhibited the enzyme activity. | TẠP CHÍ PHÁT TRIỂN KH CN TẬP 9 SÓ 5 -2006 CHARACTERIZATION OF PROTEASE FROM ASPERGILLUS ORYZAE SURFACE CULTURE AND APPLICATION IN FISH SAUCE PROCESSING Le Van Viet Man Tran Thi Anh Tuyet Department of Food Technology University of Technology VNU-HCM Manuscript Received on August 08th 2005 Manuscript Revised May 17th 2006 ABSTRACT Some kinetic parameters of the purified protease from Aspergillus oryzae surface culture were determined Km L and Vmax . Ions Na Zn2 and Fe3 had an inhibitor effect to the enzyme activity. On the contrary ion Mg 2 had an activator effect. The influence of ion Ca2 to the protease activity was more complicated. With low concentration this ion activated the protease but with higher concentration it inhibited the enzyme activity. The purified protease was applied in fish sauce processing for proteolysis acceleration. High salt content 25 in the fish-salt mixture decreased obviously the enzyme activity. Addition of salt and fungal protease to the fish sample with several times accelerated significantly fish proteolysis. 1. INTRODUCTION Fish sauce has been a traditional product in Vietnam. Production time of fish sauce varies from 6 to 12 months. Application of microbial protease in fish sauce processing permits to decrease the production time and increase the equipment productivity Steinkraus K. H. 1983 . Salt tolereance is an important charactersitics of commercial protease used in fish sauce processing. Different commercial enzymes with high protease activity cannot be used in fish sauce processing because the enzymes are non salt-tolerant. These proteases are significantly inhibited by a salt concentration of 10-20 . Aspergillus oryzae can produce salt-tolerant protease. In some Asian countries this fungi has widely been applied in the production of different traditional fermented foods with high salt content such as soy bean sauce. 3 This study focussed on the characterization of protease from Aspergillus .