Influences of Processing Conditions, Thickening Agents and Storage on Quality and Gamma-amino Butyric Acid Content of Germinated Brown Rice Milk

Abstract

Germinated brown rice has recently been recognized as a nutritious and functional food for human health and rice milk is known as one of the most convenient and favorable products from the germinated brown rice. In this study, effects of soaking time, ratio of rice to water, thermal treatments, different thickeners and storage temperature on gamma-amino butyric acid (GABA) content and quality characteristics of germinated brown rice milk (GBRM) were investigated. The results showed that the soaking with ratio 1:10 of rice to water for 8 hours produced the highest GABA content (304.70 µg/ml) compared to other soaking treatments. The heating treatment using 90oC was the most suitable for retaining the GABA content in the obtained GBRM. Regarding the effect of thickening formulations, the mixture of guar gum and xanthan gum created the highest stable GBRM product with the stability approximately 100% after 7 days of storage. In addition, the storage at 5oC was exhibited as the most suitable among the investigated storage conditions for the preservation of GABA content, stability and microbial quality of the GBRM.