Development of Salt-free Miso Manufacturing Technology

Abstract

The production of miso has been decreasing due to changes in eating habits and social environments. In addition, there has been a recent move towards reduced salt intake to diminish lifestyle-related diseases. To maintain the demand for miso, it is important to develop salt-free miso manufacturing technology. Thus, collaborative research involving industry, academia, and the government was conducted to develop salt-free miso. The production of salt-free miso requires the control of lactic acid bacteria, spore-forming bacteria, and hygiene-related bacteria. In addition, it is necessary to propagate specific fermentation microorganisms such as yeast and lactic acid bacteria to improve the taste of miso soup. Here, miso production was divided into two steps. In the high-temperature digestion step, miso was heated to 55°Cand the temperature was maintained for 1 to 5 days. In the second, low-temperature addition and multistage fermentation step, a fermentation microorganism corresponding to the desired product quality was added at a temperature of approximately 10°Cand the fermentation temperature was then raised in multiple steps. The microflora produced in each manufacturing step was analyzed by PCR-DGGE to identify hygiene-related bacteria and lactic acid bacteria. Processing conditions during the high-temperature digestion step were set as the critical control point in manufacturing.