High Gamma-aminobutyric Acid Content Research Articles

The Potential of Traditional ‘Gaja’ and New Breed Lines of Waxy, Blue and Purple Wheat in Wholemeal Flour Fermentation

The aim of this study was to analyse and compare the acidity, microbiological and colour characteristics, fatty (FA) and amino (AA) acid profiles, biogenic amine (BA) and gamma-aminobutyric acid (GABA) concentrations, and macro- and microelement contents in non-treated (non-fermented) and fermented wholemeal cereal flours of ‘Gaja’ (traditional wheat) and new breed lines DS8888-3-6 (waxy wheat), DS8548-7 (blue wheat) and DS8535-2 (purple wheat). Independent fermentations were undertaken with selected strains of Pediococcus acidilactici, Liquorilactobacillus uvarum and Lactiplantibacillus plantarum. The results revealed that all the wholemeal cereal flours of the analysed wheat varieties are suitable for fermentation with the selected strains because all the fermented samples showed lactic acid bacteria (LAB) viable counts higher than 8.00 log10 CFU/g and desirable low pH values. In most of the cases, fermentation increased the concentration of essential amino acids in the wholemeal cereal samples, and the LAB strain used for fermentation proved to be a significant factor in all the essential amino acid content of wholemeal wheat (p ≤ 0.0001). When comparing the non-fermented samples, the highest GABA content was found in ‘Gaja’ and waxy wheat samples (2.47 µmol/g, on average), and, in all the cases, fermentation significantly increased GABA concentration in the wholemeal cereals. On the other hand, total levels of biogenic amines in wholemeal samples ranged from 22.7 to 416 mg/kg. The wheat variety was a significant factor in all the analysed macro- and microelement contents (p ≤ 0.0001) in the wholemeal cereals. Furthermore, fermentation showed to be a significant factor in most of the FA content of the wholemeal cereal samples. Finally, fermentation can also contribute to improving the biological and functional value of wholemeal wheat flours (by increasing essential amino acids and GABA concentrations); however, safety parameters (e.g., biogenic amines) also should be taken into consideration when optimizing the most appropriate technological parameters.

Production of gamma-aminobutyric acid (GABA) by Bacillus subtilis BBEL02 fermentation using nitrogen-rich industrial wastes as crude feedstocks

Industrial-scale fermentation of γ-aminobutyric acid (GABA) is often limited by high cost of the starting raw materials. Increasing commercial applications of GABA in various industries have urged the research on finding the alternative substrates for the GABA production. The effects of concentration of different types of carbon and nitrogen sources; concentration of monosodium glutamate (MSG) in the defined medium for GABA production using the newly isolated Bacillus subtilis BBEL02 were studied. The feasibility of corn steep liquor (CSL) and soybean hydrolysate (SBH) as the replacement of nitrogen sources in the fermentation media for GABA production was also investigated. Highest GABA content (10.9 gL−1) and productivity (3.7 gL−1d−1) were achieved with defined medium containing 1 % (w/v) glucose, 2 % (v/v) SBH and 5 % (w/v) MSG. Dissolved oxygen (DO) of 80 % in 2-L fermenter presented the highest productivity (4.2 gL−1d−1) and GABA concentration (12.5 gL−1), however DO of 50 % was preferred because of the lower rotation speed to prevent cells deterioration.

Functional Food-drunk Crab with High GABA Production Obtained by Inoculating Fermentation Broth of <i>Lactobacillus brevisZ-215</i> and Crab by-products into Drunk Crab

Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter of the central nervous system and has various physiological functions. Recently, researchers have become interested in GABA-rich functional food design. Our laboratory obtained a strain named Lactobacillus brevisZ-215 with a high GABA production, which was used in previous studies. In this paper, we attempted to develop a GABA-rich drunk crab product using L. brevisZ-215 and crab by-products fermentation broth. The results revealed that the drunk crab products with the addition of bacterial and fermentation broths have high GABA content, close to 3 mg/mL. Furthermore, we improved the nutrition and flavor of the functional drunk crab. Additionally, we analyzed the shelf-life of drunken crabs by measuring the GABA content, pH, total volatile basic nitrogen, thiobarbituric acid, biogenic amine content, and colony count. The results of the measurements showed that the shelf-life was significantly longer compared to the uninoculated drunken crab and that the biogenic amine content was significantly suppressed.

The yield, nutritional value, umami components and mineral contents of the first-flush and second-flush Pleurotus pulmonarius mushrooms grown on three forestry wastes

This study was carried out to evaluate the yields and quality of the first-flush and second-flush Pleurotus pulmonarius mushrooms grown on three forestry wastes (pine, poplar, and honeysuckle rattan). The biological efficiency (BE) of the substrates varied from 61.89% to 81.01%. The total protein content, gamma-aminobutyric acid (GABA) content and equivalent umami concentration (EUC) values of the mushrooms were greatly influenced by the flush number and the substrate, however, the total sugar content and ergosterol content of the mushrooms were not significantly affected. The first-flush mushrooms that were grown on the pine sawdust-based substrate had the highest protein content, and the first-flush mushrooms that were grown on the honeysuckle rattan sawdust-based substrate had the highest GABA content and EUC values. All the mushroom samples accumulated Cu but excluded Ca, Mn, Pb, Cr, and Cd, and the concentrations of Mg, Fe, and Mn are species and flush number dependent.

Effect of solvent concentrations on antioxidant activity and biochemical parameters of adzuki bean (Vigna angularis) sprouts at different germination times

In this study were determined DPPH radical scavenging power, metal-ion chelating activity, gamma aminobutyric acid and phytic acid levels, total phenolic substance content, extraction yield in water and various organic solvents (acetone, n-hexane and ethanol), concentrations (50, 70 and 90%) and germination times (0, 24, 48, 72, 96 and 120 h) of adzuki bean (Vigna angularis) sprouts. The extraction yield ranged from 11.47% (H3) to 28.55% (E1). The highest DPPH radical scavenging capacity was determined at E2 concentration (2.978 µmol/g DW) for 120 h (P<0.05). E3 (1.744 mg EDTA equivalent/100 g) and A3 (1.145 mg EDTA equivalent/100 g) showed the highest metal chelating activity after 48h of germination. This activity decreased in the germination period from 48 h to 120 h (P<0.05). When different solvent concentrations were compared no significant change (P>0.05) in gamma aminobutyric acid and phytic acid contents at 0, 24 and 48 h analyses. The highest gamma aminobutyric acid content was detected to A1 (67.29 mg/100 g DW) and H1 (69.17 mg/100 g DW) concentrations at 120 h (P<0.05). No significant changes were found in total phenol content in all solvent concentrations in 48 h (P>0.05). At the end of 120 h, total phenolic components were determined in the lowest levels in W and the highest concentrations in E2 (P<0.05). These results showed that adzuki bean seeds may be more effective in these parameters, depending on the increase in the activities of bioactive components and the decrease in anti-nutritional factors, and the concentration in water and aqueous organic solvents with the increase of germination time.

Effects of germination time on the structural, physicochemical and functional properties of brown rice

SummaryGerminated brown rice (GBR) is a gluten‐free food raw material. Its tissue structure, physicochemical properties and functional properties depend on the germination time. In this study, rapid viscosity analyses, differential scanning calorimetry and X‐ray diffraction et al were used to analyse the structural, physicochemical and functional changes in brown rice (BR) during germination. Gamma‐aminobutyric acid (GABA), total phenolic compound, glutathione (GSH) and amino acid contents increased during germination. GBR exhibited the highest GSH (22.70 mg per 100 g) and amino acid (8.02 mg per 100 g) contents at 24 h and the highest GABA content (253.35 mg per 100 g) at 36 h. Furthermore, BR germinated for 36 h showed greater enthalpy (ΔH) than ungerminated BR. Although GBR showed less crystallinity than ungerminated BR, germination did not change the crystalline structure type of starch (A‐type). These results inform choices of the appropriate applications of GBR to promote its utilisation in the food industry.

Microwave drying of germinated brown rice: Correlation of drying characteristics with the final quality

Drying characteristics influence the formation of quality including visual color and gamma-aminobutyric acid (GABA) of germinated brown rice (GBR) subjected to microwave drying. In microwave drying, microwave intensities induced microscopic pores inside GBR to enhance the drying rate in initial stage, while rising temperatures caused gelatinization of starch granules to hinder the drying rate in later stage. The higher microwave intensity resulted in the greater non-uniformity of temperature inside the grain layer, which dominated the moisture content and final quality indexes of GBR. However, the coupling effects of temperature rising and moisture reducing failed to stimulate the glutamate decarboxylase (GAD) activity for the GABA synthesis, but may cause the degradation of GABA. The non-uniformity of microwave drying influenced the evaluation of GABA content in the dried GBR, and the suitable average grain temperature of 64–67 °C may retain relatively high GABA content. The critical temperature for preventing the serious browning and charred kernels inside the grain layer was 132 °C and 170 °C, respectively. Microwave intensity of 3–4 W/g may be suitable for drying of GBR considering high drying efficiency and product quality.

Differences in the Concentration of the Fecal Neurotransmitters GABA and Glutamate Are Associated with Microbial Composition among Healthy Human Subjects.

Recent studies have shown that the gut microbiota modulates the physical and psychological functions of the host through several modes of action. One of them is mediating the production of active neurotransmitters, such as serotonin and gamma-aminobutyric acid (GABA). GABA is the major inhibitory neurotransmitter in the central nervous system. Here, we analyzed the relationship between fecal GABA concentration and microbial composition in more than 70 human participants. The gut microbiome composition was analyzed using next-generation sequencing based on 16S ribosomal RNA. High-performance liquid chromatography was used to evaluate the neurotransmitters GABA and glutamate. The GABA level was detected in a broad range (0–330 µg/g feces). The participants’ samples were classified into high (>100 µg/g), medium (10–100 µg/g), and low (<10 µg/g) groups, based on fecal GABA concentration. The results reveal that the microbiome of the high-GABA samples had lower alpha diversity than the other samples. Beta diversity analysis showed significant (p < 0.05) separation between the high-GABA samples and others. Furthermore, we surveyed the abundance of specific GABA producer biomarkers among the microbiomes of tested samples. The family Bifidobacteriaceae exhibited high abundance in the microbiome of the high-GABA group. This study demonstrated that Bifidobacterium abundance was associated with high fecal GABA content in healthy human subjects. These results may aid the development of potential probiotics to improve microbial GABA production, which can support the maintenance of the physical and psychiatric health of the host.

Screening of GABA-Producing Lactic Acid Bacteria from Thai Fermented Foods and Probiotic Potential of Levilactobacillus brevis F064A for GABA-Fermented Mulberry Juice Production

Gamma-aminobutyric acid (GABA), the inhibitory neurotransmitter, can be naturally synthesized by a group of lactic acid bacteria (LAB) which is commonly found in rich carbohydrate materials such as fruits and fermented foods. Thirty-six isolates of GABA-producing LAB were obtained from Thai fermented foods. Among these, Levilactobacillus brevis F064A isolated from Thai fermented sausage displayed high GABA content, 2.85 ± 0.10 mg/mL and could tolerate acidic pH and bile salts indicating a promising probiotic. Mulberry (Morus sp.) is widely grown in Thailand. Many mulberry fruits are left to deteriorate during the high season. To increase its value, mulberry juice was prepared and added to monosodium glutamate (MSG), 2% (w/v) prior to inoculation with 5% (v/v) of L. brevis F064A and incubated at 37 °C for 48 h to obtain the GABA-fermented mulberry juice (GABA-FMJ). The GABA-FMJ obtained had 3.31 ± 0.06 mg/mL of GABA content, 5.58 ± 0.52 mg gallic acid equivalent/mL of antioxidant activity, 234.68 ± 15.53 mg cyanidin-3-glucoside/mL of anthocyanin, an ability to inhibit growth of Bacillus cereus TISTR 687, Salmonella Typhi DMST 22842 and Shigella dysenteriae DMST 1511, and 10.54 ± 0.5 log10 colony-forming units (CFU)/mL of viable L. brevis F064A cell count. This GABA-FMJ was considered as a potential naturally functional food for human of all ages.

Effect of processing conditions on bioactive compounds and glycemic index of the selected landrace rice variety in pre-diabetes

Paddy processing can affect glycemic index (GI) and bioactive compounds of rice. Therefore, the effects of processing conditions such as germination, parboiling and polishing on total polyphenols, ferulic acid and gamma-aminobutyric acid (GABA) contents of seven landrace varieties from Thailand were investigated. Subsequently, the best rice variety was chosen to evaluate GI in pre-diabetic subjects. Four different rice forms used were brown rice (BR), parboiled brown rice (PBR), germinated parboiled brown rice (GPBR) and polished rice (PR). Results showed that polishing process strongly reduced all bioactive compounds. In contrast, parboiling the grains slightly increased polyphenol, and germination followed by parboiling significantly increased polyphenol content. Ferulic acid content was found to be similar among BR, PBR and GPBR and the highest GABA content was found in GPBR. Furthermore, Leuang Awn variety exhibited the highest polyphenol (126.70 ± 1.08 mg GAE/100 g), ferulic acid (17.77 ± 0.16 mg/100 g) and GABA content (78.57 ± 1.00 mg/100 g) and was selected for GI study. PBR and GPBR had medium GI values (55.10 ± 5.37 and 60.58 ± 6.48) and PR showed high GI value (83.10 ± 5.10). In conclusion, parboiling and germination had less effects on the bioactive compounds of whole grain rice and produced low-medium GI, which could be beneficial for health promotion.

Effect of fermented oyster extract on growth promotion in Sprague–Dawley rats

BackgroundOysters (Crassostrea gigas) are a popular marine product worldwide and have the advantage of nutritional benefits. This study aimed to investigate the effect of fermented oyster extract (FO) on growth promotion, including analysis of body size, bone microarchitecture, hematology and biochemistry in vivo. MethodsThe amount of nutrients and gamma aminobutyric acid (GABA) were determined. Sprague–Dawley rats were randomly divided into four groups: the control group, FO 50 group (FO 50mg/kg), and FO 100 group (FO 100mg/kg) were administered orally once daily and the recombinant human growth hormone (rhGH) group (200μg/kg) was intraperitoneally injected once daily for 14 days. ResultsOral administration of FO 100 significantly increased body length and had no effect on organ damage or hematological profiles. However, administration of rhGH significantly induced hypertrophy of the liver, kidney and spleen along with a marked increase in body length. Tibia length and the growth plate were increased, and bone morphometric parameters were slightly improved by FO and rhGH administration. Serum analysis showed that the levels of GH and insulin like growth factor-1 (IGF-1) were slightly upregulated by FO administration. Nevertheless, the protein expression of hepatic IGF-1 was markedly increased by FO 100 and rhGH administration. ConclusionsFO have high content of GABA, and induced positive effects on body length, tibial length, growth-plate length and hepatic IGF-1 synthesis in SD rats with no toxicity or alterations of hematological profile. Therefore, these results suggest that GABA-enriched FO could be considered a potential alternative treatment for growth stimulation.

Localization of amino acids in germinated rice grain: Gamma-aminobutyric acid and essential amino acids production approach

Germinated rice is popularly consumed for its high gamma-aminobutyric acid (GABA) and bioactive compounds. Supporting information on how to germinate rice with high GABA content and essential amino acids is lacking. White and colored rough rice were germinated for 0, 24, 48, 72, 96, 120 and 144 h. GABA, GABA substrates and essential amino acids were also investigated using GC-MS and MALDI-MSI. GABA was more concentrated after germination and shifted into the coleoptile. High correlation was recorded between germination time and GABA (0.79–0.83, p ≤ 0.01) and glutamic acid (0.88–0.89, p ≤ 0.01). Highest rates of GABA and glutamic production were observed within 48 h of germination in both rice varieties (26.12 and 34.28 mg/100g) and reached maximum value at 96 h (31.36 and 38.75 mg/100g). Colored rice germination showed higher GABA, GABA substrates and deficient amino acids than white rice. GABA and essential amino acids drastically increased after germination, supporting the consumption of germinated rice as a functional food.

Effect of Feeding High Gamma-Aminobutyric Acid-Containing Giant Embryo Black Sticky Rice (Oryza sativa L.) on Anxiety-Related Behavior of C57BL/6 Mice.

The aim of this study was to determine the effect of feeding high gamma-aminobutyric acid (GABA)-containing black sticky rice giant embryo (BSRGE, Oryza sativa L.) on anxiety-related behavior of C57BL/6 mice. Experimental feedstuff (BSRGE with high GABA+AIN-76A) and control (AIN-76A) were provided to C57BL/6 mouse for 10 days. Antianxiety effects of BSRGE with high GABA were measured using an elevated plus maze. On day 8, the number of open arm entries by GABA and control groups were 1.10 ± 1.60 (mean ± SD) and 0.00 ± 0.00 (P = .030). On day 10, the number of open arm entries by the GABA group was 2.00 ± 1.89, which was significantly (P = .025) higher than that in the control group (0.40 ± 0.84). On day 8, the time the mice spent in open arm in the GABA group and control group was 3.60 ± 7.06 and 0.00 ± 0.00 sec (P = .068), respectively. On day 10, the time the mice in the GABA and control groups spent in open arm was 6.20 ± 5.35 sec and 1.80 ± 3.82 sec (P = .042), respectively. In repeated analysis of variance for the number of entries into open arm and time spent in open arm, significant differences were found between the two groups. Therefore, BSRGE with high GABA content might have an antianxiety effect. This study can serve as a preliminary study so that further antianxiety effects of BSRGE can be determined in more extended animal or clinical research studies in the future.

GABA (γ-aminobutyric acid) production, antioxidant activity in some germinated dietary seeds and the effect of cooking on their GABA content

Germinated grains have been known as sources of Gamma-aminobutyric acid (GABA) that provide beneficial effects for human health. This study was aimed to investigate GABA production, dietary fiber, antioxidant activity, and the effect of cooking on GABA loss in germinated legumes and sesame. The highest GABA content was found in germinated mung bean, (0.8068 g kg-1, 24 h incubation) followed by germinated soybean, germinated black bean and soaked sesame. Beside GABA, dietary fiber content also increased in all grains during germination where the insoluble dietary fiber fractions were always found in higher proportions to soluble dietary fiber fractions. Our results also confirmed that germinated mung bean is a rich source of GABA and dietary fibers. Microwave cooking resulted in the smallest loss of GABA in mung bean and sesame, while steaming led to the least GABA content loss in soybean and black bean. Therefore microwave cooking and steaming are the most recommended cooking processes to preserve GABA in germinated legumes and sesame.

Quality Characteristics of a Pickled Tea Processed by Submerged Fermentation

There is a traditional pickled tea fermented under anaerobic condition in many Asian countries, but its quality characteristics are still unclear. The dynamic qualities, chemical components, and volatile components of pickled tea processed by submerged fermentation were investigated. The results showed that the sensory qualities of the pickled tea gradually improved with increasing fermentation time. Sensory qualities decreased gradually after 7 d of fermentation, and the change was extremely significant (p < 0.01). Correspondingly, biochemical indicators (except for soluble extract) decreased continuously and significantly (p < 0.01) within 5–7 d of fermentation, but the decrease was much slower in the later stage. The proper control of fermentation time is a key step for obtaining the desired quality of pickled tea. By submerged fermentation for 7 d, the best sensory quality of pickled tea was obtained: the taste of pickled tea was less bitter and astringent, but certainly acidic; the flavor of pickled tea was sour with sweet and floral tastes; the tea had low caffeine content, high gamma-amino butyric acid content, and high contents of special volatile components, such as hotrienol and 2,6-bis (1,1-dimethylethyl)-4-methyl-phenol. Results indicated that submerged fermentation is potentially a new method of processing pickled tea to obtain the desired quality. Our results contribute to the understanding of the microbial transformation of tea components under anaerobic conditions.

전통 제주방법인 급청주법으로 제조한 가바쌀막걸리의 품질 특성

This study was performed to elucidate the fermentation and sensory characteristics of Korean traditional rice wine, makgeolli, made from GABA rice, which has a high content of GABA (gamma-aminobutyric acid). GABA rice is a brown rice that is not easily fermented by general makgeolli manufacturing methods. Thus, the Geupchungju method, which is a Korean traditional manufacturing method for makgeolli using a fermentation starter and additional malt, was considered for making makgeolli from GABA rice. We confirmed that Geupchungju method showed a high saccharification and stable alcohol fermentation ability in the early stages of fermentation. However, malt addition more than 2% resulted in a lower score in the sensory evaluation of the final product. It was also confirmed that GABA content of GABA makgeolli was higher than that of commercial makgeolli by 2.3-fold. Our result provides useful information toward improving quality of brown rice makgeolli.

Optimizing soaking and germination conditions to improve gamma-aminobutyric acid content in japonica and indica germinated brown rice

Germinated brown rice is a well-known functional food due to its high content of gamma-aminobutyric acid (GABA). This study was designed to test the difference of producing GABA in two domesticated rice genotypes (indica and japonica rice), and the effects of adding exogenous glutamic acid or gibberellin, and processing conditions. Soaking at 30 °C and germination at 35 °C during 36 h resulted in the highest GABA in distilled soaking water with pH 7. The indica rice showed higher GABA levels than japonica rice. GABA was increased under acidic soaking conditions or by adding L-glutamic acid (L-Glu) at the optimal concentration of 1.0 g L−1 and gibberellin A3 (GA3) at the optimal concentration of 0.25 mg L−1. The lower accumulation of GABA in japonica rice could be remedied by adding exogenous L-Glu and GA3, and providing acidic soaking conditions. The results help to efficiently produce GABA enriched functional food.

발아보리를 이용한 고추장 당화물의 품질특성

Germination conditions were evaluated to obtain barley containing a high content of gamma-aminobutyric acid (GABA), and quality characteristics of saccharified materials manufactured using germinated barley were investigated. Water absorption content of barley increased but pH of the steeping solution decreased with increasing steeping time at all steeping temperatures. The changes in water absorption content and pH were highest at a steeping temperature of . The highest GABA content was obtained at a steeping condition of for 20 h. The highest GABA content was obtained for a germination condition of for 36 h after steeping, resulting in an increase of 7.4 times more GABA contents than that in raw material. The pH of saccarified materials decreased but titratable acidity, amino type nitrogen content, and ammonia type nitrogen content increased during the saccharification period. GABA content of saccarified materials increased with increasing saccharification period, resulting in the highest GABA content from saccarified materials containing germinated barley.

Separation of gamma-aminobutyric acid from fermented broth

Gamma-aminobutyric acid (GABA) is a non-proteinaceous amino acid that is widely distributed in nature and acts as the major inhibitory neurotransmitter in the mammalian brain. This study aimed to find a separation method for getting high-purity GABA from a fermented broth. Firstly, a fermented broth with a high content of GABA (reaching 997 ± 51 mM) was prepared by fermentation with Lactobacillus brevis NCL912. GABA purification was conducted by successive centrifugation, filtration, decoloration, desalination, ion-exchange chromatography (IEC), and crystallization. Inorganic salt (Na₂SO₄) was removed from the both by desalination with 70% ethanol solution. A ninhydrin test strip was designed for the real-time detection of GABA during IEC. The recovery rate for the whole purification process was about 50%. The purified product was characterized by thin-layer chromatography and HPLC, and its purity reached 98.66 ± 2.36%.

Germination Conditions Affect Physicochemical Properties of Germinated Brown Rice Flour

Germinated brown rice has been reported to be nutritious due to increased free gamma-aminobutyric acid (GABA). The physicochemical properties of brown rice (BR) and glutinous brown rice (GNBR) after germination as affected by different steeping times (24, 36, 48, and 72 h depending on the rice variety) and pHs of steeping water (3, 5, 7, and as-is) were determined and compared to those of the nongerminated one (control). As the steeping time increased or pH of steeping water decreased, germinated brown rice flours (GBRF) from both BR and GNBR had greater reducing sugar, free GABA and alpha-amylase activity; while the total starch and viscosity were lower than their respective controls. GBRFs from both BR and GNBR prepared after 24-h steeping time at pH 3 contained a high content of free GABA at 32.70 and 30.69 mg/100 g flour, respectively. The peak viscosity of GBRF obtained from both BR and GNBR (7.42 to 228.22 and 4.42 to 58.67 RVU, respectively) was significantly lower than that of their controls (255.46 and 190.17 RVU, respectively). The principal component analysis indicated that the important variables for discriminating among GBRFs, explained by the first 2 components at 89.82% of total explained variance, were the pasting profiles, alpha-amylase activity, and free GABA.