Dynamic Changes in γ-Aminobutyric Acid and Glutamate Decarboxylase Activity in Oats (Avena nuda L.) during Steeping and Germination

Abstract

Gamma-aminobutyric acid (GABA) is the principal inhibitory neurotransmitter in the central nervous system and provides beneficial effects for human and other animals health. To accumulate GABA, samples from two different naked oat cultivars, Baiyan II and Bayou I, were steeped and germinated in an incubator. The content of GABA and glutamic acid as well as the activity of the glutamate decarboxylase (GAD) in oats during steeping and germination were investigated with an amino acid automatic analyzer. Compared with raw groats, an increase in GABA content of oat groats during steeping and germination was continuously observed for two oat cultivars. The activity of GAD increased greatly at the end of steeping and the second stage of germination for Baiyan II and Bayou I, respectively. Glutamic acid content of treated oat groats was significantly lower than that in raw groats until the later period of germination. GABA was correlated (p<0.01) significantly and positively with the glutamic acid rather than GAD activity in the current study. The results indicates that steeping and germination process under highly controlled conditions can effectively accumulate the GABA in oat groats for Baiyan II and Bayou I, which would greatly facilitate production of nutraceuticals or food ingredients that enable consumers to gain greater access to the health benefits of oats. However, more assays need to be further performed with more oat cultivars.

Response surface optimisation of germination conditions to improve the accumulation of bioactive compounds and the antioxidant activity in quinoa

“…GABA is primarily synthesised from glutamic acid by glutamate decarboxylase (GAD), but it can be also formed from polyamines via c-aminobutyraldehyde intermediate, being diamine oxidase (DAO) and amino aldehyde dehydrogenase (AMADH) the enzymes involved in the process. Several studies have demonstrated that the activity of GAD and DAO is significantly increased during germination in cereals and legumes (Xu et al, 2010;Yang et al, 2011;Xu & Hu, 2014;Gan et al, 2017), phenomenon that would explain the accumulation of GABA in quinoa sprouts. In fact, it has been reported that the suitable temperature for improving GAD activity and enhances GABA content is 30°C (Guo et al, 2011;Xu & Hu, 2014), findings that support the results of the present study.…”

Changes in physicochemical characteristics and free amino acids of hawthorn (Crataegus pinnatifida) fruits during maturation

“…Sample concentrations were calculated, based on peak areas compared to those of each of the external standards. The concentration of free amino acids was determined following the method described by Xu, Hu, Duan and Tian (2010) with some modifications. Briefly, the free amino acid extracts were filtered through a 0.45 µm of nylon syringe filter (Filtrex Technology, Singapore) prior to analysis and analyzed by a Biochrom 30 series Amino Acid Analyzer (Biochrom Ltd., Cambridge Science Park, England) with a Na-cation-exchange column (8 µm, 4.6mm × 200 mm).…”

1H-NMR metabolomics analysis of nutritional components from two kinds of freshwater fish brain extracts

“…32 Choline can modulate the basic singling processes within cells as a structural element in membranes, it is crucial in brain development for most living organisms. 33 GABA is a non-protein amino acid with four free carbons and it is also considered as the major inhibitory neurotransmitter in CNS, which was involved in the regulation of cardiovascular function and provided positive effects of many neurological disorders such as Huntington's disease, Parkinson's disease, senile dementia, seizures, and Alzheimer's disease [34][35][36] etc.…”