Journal of Taiwan Agricultural Research

Author:Shwu-Jene Tsai* and Tsung-Yen Wu

Abstract:

    Fermented rice dreg is a valuable by-product of rice wine manufacture.  This study was carried out to determine effects of yeast strains and distillation on nutritional components of rice dregs using rice variety TNG-71.  Wine fermentations of steamed or non-steamed rice were inoculated with different commercial strains of yeast (Scharomyces cerevisiae).  At the end of ambient fermentation, the solid dregs were separated from thin stillage and then used for chemical analyses.  Results showed that the nutritional composition of rice dregs was affected by strains of yeast as well as the source of rice grain (steamed or non-steamed).  For examples, crude protein, the main ingredient of rice dregs, was 77.19, 66.16 and 59.67% for the treatments of yeast strain Fermivin PDM® in steamed rice, yeast strain Danstil B® in steamed rice, and yeast strain Magic Koji® in non-steamed rice, respectively.  In addition, there was a positive correlation (p < 0.05) between dried yield and protein contents of rice dregs.  Compared to fermented steamed rice, the rice dregs from fermentation of non-steamed rice had lower protein content but higher fiber and lipid.  Since distillation of fermented mash is an important processing for spirit production from rice, the chemical composition of distilled and non-distilled dregs was compared.  Results showed that the distilled rice dregs had lower protein but higher fat, fiber, ash, carbohydrate, free sugar and amylose, compared to the non-distilled rice dregs.  Unlike the reported low protein of lignocellulosic distillers’ grains, the dreg from rice wine manufacture contains high protein, and thus, may serve as a potential source of plant protein for food.

Key words:Rice, Rice dregs, Chemical composition, Yeast, Fermentation, Distillation

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