Research on the development of Value-added Vinegar using Subcritical Treated Water

Sake lees and rice bran, which are residues from food processing, were liquefied by subcritical water treatment to effectively produce new vinegar. Our previous studies reported that high concentrations of amino acids can be recovered from sake lees treated with subcritical water at 120°C for 240 min [1,2]. In this study, the conditions for subcritical water treatment of rice bran were examined, and a liquefied product with a high liquefaction rate and high mineral content was obtained at 180°C for 30 min. Acetic acid fermentation was then conducted with a ratio of sake lees liquefied product to rice bran liquefied product of 1:1. The resulting vinegar had a high nutritional value similar to commercially available black vinegar.