Autolysis of unsalted fish protein under pressurization

Abstract

For the purpose of producing fish sauce without any addition of salt, an autolytic technique under pressurization combined with warming was investigated. While rancidity caused by the autolysis could be inhibited by pressurization at higher than 50 MPa combined with warming at 50°C, the effect of pressurization on the autolysis was not observed in the range of 50-250 MPa. The optimum temperature and treatment time for the autolysis under pressurization were 50°C and 48 h, respectively. The extract of anchovy produced under the autolysis conditions under 60 MPa at 50°C for 48 h contained 2.6% total nitrogen, 1.4% formol nitrogen, and 11.6% free amino acids by weight. These contents were higher than those of commercially available fish sauce and soy sauce. The sensory test revealed that saltiness was hardly perceived, and odors like ‘cheesy’ and ‘rancid’ were not as strong as in fish sauce. Thus, this autolytic technique under pressurization combined with warming could be a new method for producing a good-quality autolytic extract similar to fish sauce without any addition of salt in an extremely short period of time.