Effect of different germination conditions on antioxidative properties and bioactive compounds of germinated brown rice.

You-Tung Lin,Cheng-Cheng Pao,Chi-Yue Chang,Shwu-Tzy Wu

doi:10.1155/2015/608761

Abstract

This study investigates antioxidative activity and bioactive compounds of ungerminated brown rice (UBR) and germinated brown rice (GBR). We used two rice cultivars (Oryza sativa L.), Taiwan Japonica 9 (TJ-9) and Taichung Indica 10 (TCI-10), as the materials in our experiments. The conditions for inducing germination are soaking time in water 24, 48, or 72 h; temperature 26 or 36°C; incubation in light or darkness; and open or closed vessels, in which the antioxidative activities and bioactive compounds of GBR were determined. We found that, in order to maximize antioxidative activity and bioactive compounds, germination should be under higher temperature (36°C), long soaking time (72 h), darkness, and closed vessel. GBR contains much higher levels of antioxidative activity and bioactive compounds than ungerminated brown rice (UBR). We found a strong correlation between antioxidative activities (DPPH radical scavenging ability, reducing power, and Trolox equivalent antioxidant capacity) and bioactive compounds (γ-oryzanols, tocopherol, and tocotrienol). Higher temperature (36°C) is also conducive to the production of GABA in GBR. These results are considered very useful research references for the development of future functional foods and additives.

Highlights

Rice accounts for over 22% of global calories intake
Fifty samples were used in the experiments for measuring antioxidative activity (DPPH radical scavenging effects, reducing power, and Trolox Equivalent Antioxidant Capacity (TEAC))
These 50 samples include two ungerminated brown rice (TJ-9 and Taichung Indica 10 (TCI-10)) and 48 germinated brown rice (TJ-9 and TCI-10 germinated under 24 different conditions) cultivars

Summary

Introduction

Rice accounts for over 22% of global calories intake. More than 90% of the world’s rice is grown and consumed in Asia [1]. GBR is produced by soaking brown rice grains in water to promote germination, and γaminobutyric acid (GABA) is formed during this process [7]. Key bioactive compounds in GBR, for example, GABA, dietary fibre, ferulic acid, tocotrienols, magnesium, potassium, zinc, γ-oryzanol, and prolyl endopeptidase inhibitor, increase significantly in brown rice after germination [8]. When these bioactive compounds in GBR were benchmarked against those of milled ungerminated brown rice, they were 10 times greater in GABA, nearly four times greater in dietary fibre, vitamin E, niacin, and lysine, and three times greater in thiamine, pyridoxine, and magnesium [8]. GBR extracts contain GABA which can inhibit cancer cell from spreading [12]

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