Effects of steeping and anaerobic treatment on GABA (γ-aminobutyric acid) content in germinated waxy hull-less barley

Hyun Jung Chung, Su Hae Jang, Hong Yon Cho, Seung Taik Lim

Research output: Contribution to journalArticle

84 Citations (Scopus)

Abstract

Effects of steeping conditions (time, temperature and soaking solution) and anaerobic storage on the gamma-aminobutyric acid (GABA) content in waxy hull-less barley grains during germination was examined. The barley kernel was steeped for 16 h at different temperatures (5, 15 or 35 °C) either in water or in a buffer solution (pH 6.0, 50 mmol/L sodium acetate) and then germinated at 15 °C for 72 h. To reach the optimum water content (36-44 g/100 g) for germination, a longer steeping period was required when steeping temperature was lower (16 h at 5 °C vs. 8 h at 15 °C). At 35 °C for steeping, however, the water content in the grains increased excessively, and thus germination percentage became much less than those at 5 and 15 °C. The GABA content increased with increasing germination time and was higher in the buffer solution than water. These findings indicate that the glutamate decarboxylase (GAD), which is the rate-limiting enzyme for GABA synthesis, is more activated by extending germination at controlled pH (6.0). An anaerobic storage with nitrogen in the dark for the germinated barley grains substantially raised the GABA content: 14.3 mg/100 g after the treatment for 12 h, which was four times higher than that of control sample (3.7 mg/100 g). Overall results suggest that the steeping prior to germination greatly affects the GABA production during the germination of barley, and the anoxia storage with nitrogen after the germination increases the GABA content.

Original languageEnglish
Pages (from-to)1712-1716
Number of pages5
JournalLWT - Food Science and Technology
Volume42
Issue number10
DOIs
Publication statusPublished - 2009 Dec

Keywords

  • Anaerobic treatment
  • Barley
  • Gamma-aminobutyric acid (GABA)
  • Germination
  • Steeping

ASJC Scopus subject areas

  • Food Science

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