Removal of Crude Fat from Rice-Koji, and Preparation of Bacterial-Free Dehydrated Rice-Koji by Supercritical CO₂ Extraction

Abstract

Removal of crude fat from rice-koji by the supercritical CO₂ extraction using ethanol as an entrainer was investigated.
(1) Removing efficiency of crude fat was affected by the moisture contents of samples, and it increased by addition of ethanol. Fat-by-hydrolysis was partialy removed when ethanol was added to CO₂.
(2) The ratio of saturated fatty acid of rice-koji increased by the extraction.
(3) Each enzymatic activity was kept more than 90% after the CO₂ extraction. The addition of ethanol changed enzymatic balance.
(4) The moisture contents decreased by the extraction.
(5) When ethanol was added, samples were almost sterilized.