γ-Aminobutyric acid-enriched effervescent tablets from Lactiplantibacillus plantarum –fermented rice bran: composition, quality attributes, stability, and sensory acceptance

Effervescent tablets delivering γ-aminobutyric acid (GABA) were developed using Lactiplantibacillus plantarum-fermented rice-bran insoluble solids as a value-added ingredient derived from rice-bran by-products. Tablets were evaluated for proximate composition, GABA content, physicochemical properties, storage stability, and consumer acceptance. The product contained 22.95 ± 0.38 g/100 g ash, 3.41 ± 0.67 g/100 g crude fat, 5,740 mg/100 g sodium (approximately 230 mg per tablet), and 20.75 mg/100 g GABA (approximately 0.83 mg per tablet). Filtration of dissolved tablet solutions prior to colorimetric analysis reduced analytical variability, lowering the coefficient of variation from 35%–42% to 20%–26%. Freshly prepared tablets exhibited a weight of 4.15 ± 0.24 g, thickness of 5.03 ± 0.24 mm, disintegration time of 2 min 20 s ± 21 s, pH of 4.51 ± 0.32, CO₂ content of 360.00 ± 43.59 mg, and hardness of 7.17 ± 3.07 kg. During three months of storage at room temperature, tablet weight, thickness, and disintegration characteristics remained relatively stable, whereas pH decreased slightly and CO₂ release increased. Sensory evaluation (n = 53) indicated generally neutral consumer acceptance, with colour receiving the highest ratings. These findings demonstrate the feasibility of incorporating fermented rice-bran-derived materials into effervescent tablets, providing a convenient GABA delivery system and a promising approach for rice-bran valorisation.