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Eco-friendly pectin/BCG film sensor: a smartphone-compatible platform for gamma-aminobutyric acid detection
(2026-05-01)
Niamlaoong, Rungthiwa
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Teerasong, Saowapak
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Phengdaam, Apichat
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Tantirungrotechai, Yuthana
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Wattanasin, Panwadee
This work introduces a biodegradable pectin–bromocresol green (BCG) film integrated into a microplate platform for the colorimetric determination of gamma-aminobutyric acid (GABA). The sensing mechanism relies on electrostatic ion-pair formation between the protonated amine group of GABA (-NH₃+) and the sulfonate group of BCG, producing a distinct color transition from yellow to green. The resulting colorimetric response was quantitatively analyzed using a smartphone-assisted RGB system coupled with ImageJ software. Molecular modelling provided insight into the interaction mechanism and indicated that the GABA-BCG association is dominated by electrostatic interactions. Under optimized conditions, the developed assay exhibited a wide linear range (0.1–1000 mg L−1) with detection and quantification limits of 0.07 mg L−1 and 0.22 mg L−1, respectively. Good analytical precision was achieved (%RSD ≤ 5%), while negligible interference from common amino acids, vitamins and food additives was observed. The method was successfully applied to beverage and dietary supplement samples, demonstrating good agreement with HPLC analysis. The biodegradable BCG–pectin film platform provides a rapid, low-cost, and portable approach for GABA determination and represents a promising sensing strategy aligned with the principles of green analytical chemistry.
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Genomic comparison of gamma-aminobutyric acid-producing Levilactobacillus brevis and Companilactobacillus zhachilii strains from Thai fermented foods
(2025-01-01)
Pakdeeto, Amnat
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Phuengjayaem, Sukanya
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Kingkaew, Engkarat
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Tungkajiwangkoon, Santhita
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Phitchayaphon, Chantharat
Importance of the work: The GABA-producing Companilactobacillus zhachilii isolated from fermented pork (‘nham’) demonstrates both efficacy and safety in GABA production. Objectives: To identify the GABA-producing strains ASK-1 and ANB-1 to compare their genomes with those of Levilactobacillus brevis and Companilactobacillus zhachilii strains. Materials and Methods: Two fermented food samples were collected and used for the isolation of lactic acid bacteria. The strains obtained were evaluated for GABA production. The selected strains were identified based on their phenotypic and genotypic characteristics. Genomic comparisons of the GABA-producing strains were performed using genome sequencing, assembly, annotation and comparative analysis. This analysis included the examination of CRISPR regions, antimicrobial genes, functional attributes and genome visualization. Results: The GABA-producing lactic acid bacteria (ASK-1 and ANB-1) were isolated from traditional Thai fermented foods (‘sai-krog-prieo’ and ‘nham’). The strains ASK-1 and ANB-1 produced 9.12 ± 0.51 g/L GABA and 12.73 ± 0.57 g/L GABA, respectively. On the basis of phenotypic characteristics and 16S rRNA gene sequencing, strain ASK-1 presented 100% sequence similarity to Levilactobacillus brevis ATCC 14687T, whereas ANB-1 presented 99.93% similarity to Companilactobacillus zhachilii HBUAS52074T. Genome analysis identified ASK-1 as L. brevis ATCC 367, with an average nucleotide identity based on a BLAST (ANIb) value of 98.86% and ANB-1 with an ANIb value of 96.92%, to C. zhachilii HBUAS52074T. Additionally, genomic studies revealed GABA-producing genes (gadA and gadB) via the KofamKOALA-KEGG Orthology database. Main finding: Levilactobacillus brevisASK-1 and Companilactobacillus zhachiliiANB-1 efficiently and safely produced GABA and exhibited probiotic properties, making them promising starter cultures for functional food production in both local food and industrial fermentation processes.
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The decoration of ZnO nanoparticles by gamma aminobutyric acid, curcumin derivative and silver nanoparticles: Synthesis, characterization and antibacterial evaluation
(2021-02-01)
Talodthaisong, Chanon
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Plaeyao, Kittiya
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Mongseetong, Chatariga
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Boonta, Wissuta
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Srichaiyapol, Oranee
Zinc oxide nanoparticles (ZnO NPs) are applied in various applications in catalysis, bio-sensing, imaging, and as antibacterial agents. Here we to prepare ZnO nanomaterials decorated by γ-amino butyric acid (GABA), curcumin derivatives (CurBF2) and silver nanoparticles (CurBF2-AgNPs). The structures of all ZnO nanostructures were characterized using Fourier transform in-frared (FT-IR) spectroscopy, X-ray diffraction (XRD), UV–VIS spectrophotometry, fluorescence spectrophotometry, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HR-TEM). Further, their antibacterial activities against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria were investigated through analysis of minimum inhibitory concentration (MIC) method. Among the prepared nanostructures, the ZnO NPs-GABA/CurBF2-AgNPs showed excellent antibacterial activity against both Gram-positive and-negative bacteria. ZnO NPs fabricated here may have potential use in future anti-bacterial compositions and coatings technologies.
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Influence of geographical and genetic variation on GABA content in Annona muricata grown in Thailand
(2020-12-08)
Deewatthanawong, R.
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Tontiworachai, B.
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Kongchinda, P.
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Chanapan, S.
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Sriwilaiwan, S.
Annona is a genus of tropical fruit trees in the family Annonaceae. Fruit pulp of Annona muricata contained the highest amount of gamma-aminobutyric acid (GABA) among Annona species. GABA content results from many factors including genetic makeup and environment. Influences of genetic variation and geographical environment on GABA content in fruit pulp of A. muricata were determined. To study genetic variation, sequences of ITS2 and psbA-trnH were used to construct phylogenetic trees. Young leaves of A. muricata were collected from different geographical locations including Chumphon, Trang, Nakhon Ratchasima, Nakhon Si Thammarat, Buriram, Nong Khai, Udon Thani, and Prachuap Khiri Khan Provinces in Thailand. Sequences of ITS2 and psbA-tmH were aligned and data sets were analyzed using maximum likelihood (ML) and neighbor-joining (NJ) methods. ITS2 sequence variations were observed within and among samples from different locations. A. muricata fruit harvested from eight provinces, namely Chumpon, Trang, Nakhon Ratchasima, Nakhon Si Thammarat, Buriram, Nong Khai, Udon Thani, and Prachuap Khiri Khan contained 19.75, 35.02, 32.91, 28.18, 42.37, 32.17, 65.02, and 31.58 mg 100 g-1 FW GABA, respectively. Findings indicated that both geographical environment and genetic variation had significant effects on GABA content in A. muricata fruit.
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Development of UV-treated cooked germinated brown rice and effect of UV-C treatment on its storability, GABA content, and quality
(2016-09-01)
Jongyingcharoen, Jiraporn Sripinyowanich
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Cheevitsopon, Ekkapong
A process for preparing UV-treated cooked germinated brown rice (CGBR) was developed. The UV-C exposure time was varied to study its effect on the shelf life of CGBR at room temperature (RT; 25 ± 2 °C). The germinated brown rice with the highest GABA content was cooked and radiated with UV-C for 30 and 60 min, after which the aerobic plate count was reduced by 0.40 and 0.58 log CFU/g, respectively. Their shelf lives were 1 and 3 days, respectively. The GABA contents of control CGBR, 60-UV-CGBR, and canned CGBR were 7.49, 5.11, and 1.81 mg/100 g dry matter, respectively. The whiteness and hardness of 60-UV-CGBR were not significantly different from those of control CGBR (p ≥ 0.05). These quality attributes were poorer after canning. After storing 60-UV-CGBR at RT for 3 days, the GABA content and whiteness decreased, and the hardness increased significantly. Its quality was however better than that of canned CGBR.
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Sequential injection for determination of gamma-aminobutyric acid based on its effect on second order light scattering of silver nanoparticles
(2016-08-01)
Jinnarak, Amornrassamee
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Anantavichian, Pattarapon
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Intanin, Apichai
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Fungladda, Suchada
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Choengchan, Nathawut
An automated sequential injection (SI) with second order light scattering (SOS) detection for determination of gamma-aminobutyric acid (GABA) was developed. Quantitation is based on electrostatic interaction between GABA and citrate-capped silver nanoparticles (AgNPs). In acetate buffer at pH 3.8, the positively charged GABA induces the nanoparticles to aggregate. This results in a change of light scattering monitored using a spectrofluorometer. In this work, working standard solutions of GABA were prepared in-line by the SI system pumping appropriate volumes of a stock solution of GABA and acetate buffer into a holding coil. Solution of AgNPs was subsequently drawn into the coil. The reaction zone was then transferred to the spectrofluorometer, set with excitation and detection wavelengths at 300 and 600 nm, respectively. Under optimised condition, the SOS intensity was proportional to the concentration of GABA. As a result, a linear curve was obtained in the range of 100–400 mg L−1 GABA, with a lower limit of detection of 39.6 mg L‐1. Good precision of analysis was achieved, with 0.6 and 3.3% relative standard deviation (RSD) for external calibration (n = 5) and standard addition (n = 3), respectively. The developed method was successfully applied for quantification of GABA in dietary supplements (2 samples) and samples of instant green tea (2 samples).
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A novel colorimetric method for detection of gamma-aminobutyric acid based on silver nanoparticles
(2016-06-28)
Jinnarak, Amornrassamee
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Teerasong, Saowapak
A novel, simple and rapid colorimetric method for determination of gamma-aminobutyric acid (GABA) was developed using a negatively charged citrate-capped silver nanoparticle (AgNP) probe. At an acidic pH of 3.8, GABA had a positive charge due to a protonation of amine groups. Therefore GABA could induce an aggregation of AgNPs due to electrostatic interaction. This caused a decrease in the surface plasmon resonance spectra of the colloidal solution at wavelength of 390 nm with a slight red shift. At the same time, the color of the suspension turned from yellow to green upon aggregation. Quantification of GABA was done spectrophotometrically. Under optimum conditions, the method showed a linear calibration in range of 100-500 mg L-1 GABA, with a detection limit of 57.7 mg L-1. The method was successfully applied to measure GABA quantities in dietary supplements.
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Determination of the gamma-aminobutyric acid content of germinated brown rice by near infrared spectroscopy
(2014-01-01)
Kaewsorn, K.
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Sirisomboon, P.
Rice rich in gamma-aminobutyric acid (GABA) has been increasing in popularity worldwide, particularly within the commercially important health food market. The aim of this research was to develop a near infrared (NIR) spectroscopic method to evaluate the GABA content of germinated brown rice. Germinated brown rice (GBR) from two groups was used in this study. The first group contained GABA adjusted rice samples produced from germinated rough rice, which had been soaked for 24 h and 48 h and then incubated for 0 h, 6 h, 12 h, 18 h, 24 h, 30 h and 36 h (GBR samples). The second group was the GBR purchased from local markets (MGBR samples). The GABA content of each sample was subsequently determined by high performance liquid chromatography (HPLC). A prediction model for the GABA content was subsequently established using the NIR spectral data in conjunction with partial least square regression (PLSR), which was validated using test set validation. There were three optimal models obtained from GBR samples, MGBR-Khao Dawk Mali 105 samples and MGBR-various varieties. The first model was established using spectral data pre-treated with first derivative + multiple scatter correction and the second and third models were from first derivative + vector normalisation pre-treated spectra. The coefficient of determination (r2), root mean squared error of prediction (RMSEP) and a bias of 0.97-0.98 mg, 0.21-0.52 mg per 100 g dry matter and -0.285-0.067 mg per 100 g dry matter, respectively, were obtained. This is the first report on the application of NIR spectroscopy to evaluate the GABA content of the germinated brown rice, which could prove useful in an industrial applications and consumers. © IM Publications LLP 2014.

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