Augmentation of gamma amino butyric acid (GABA), antioxidant potential and nutrient qualities in germinated brown rice

Abstract

Listen

Translate article

Rice grains rich in GABA, a major inhibitory neurotransmitter, are gaining popularity, particularly, in the health food market, for their nutritional, brain, and nerve functions. Many factors like variety, soaking, and germination time influence GABA levels in rice. We evaluated a few indigenous rice varieties/cultivars for their potential to enhance GABA content by varying the soaking and germination durations. GABA content of rice varieties Jyothi and Chitteni and the cultivar Njavara increased steadily from 19.18 mg/kg, 26.67 mg/kg, and 28.63 mg/kg at 0 h soaking and germination to 116.89 mg/kg, 127.97 mg/kg and 130.29 mg/kg after 72 h soaking and germination. The GABA enriched rice extracts showed moderate antioxidant activity in DPPH radical scavenging activity with an IC50 value of 121.01 μg/mL, 101.38 μg/mL, 119.14 μg/mL,and high reducing activity in ferric oxide radical scavenging assay with an IC50 value of 53.81 μg/mL, 47.30 μg/mL, and 52.15 μg/mL in Jyothi, Njavara, and Chitteni, respectively. GABA content enhanced significantly with the increase in the duration of soaking and germination. The germination process for all rice varieties/cultivars significantly (P ≤ 0.05) enhanced protein, fat, and dietary fibre, while the energy and carbohydrate decreased slightly. Among the three rice varieties/cultivars, germinated brown rice from Njavara was superior, having the most GABA content, antioxidant activity, and nutritional qualities. The GABA content in the germinated Njavara was superior or comparable to the GABA content in most of the earlier reported Indian rice varieties. Germinated brown rice from indigenous rice varieties such as Njavara can be exploited as a potential source for a nutritionally rich and balanced diet.