Development of Fermented Etawa Goat Milk Containing Gamma-Aminobutyric Acid (GABA) by Indigenous Lactiplantibacillus plantarum subsp. plantarum T-3

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This research presents the use of an indigenous Lactiplantibacillus plantarum subsp. plantarum T-3 strain as a starter culture to produce fermented goat milk containing gamma-aminobutyric acid (GABA). The fermented goat milk drink was produced by inoculating Etawa goat milk with a 2 % (w/v) skim and 3 sugar treatments: No added sugar, 8 % (w/v) sucrose, and 8 % (w/v) glucose. The inoculum was a 1 % (v/v) culture of L. plantarum T-3 at a concentration of 107 colony-forming units (CFU) per milliliter. The concentration of GABA, the pH, titratable acidity, physicochemical properties of the fermented milk, including syneresis, water-holding capacity (WHC), viscosity, and sensory properties, were also evaluated. The product was stored for 5 weeks to ascertain its stability. The concentration of GABA increased significantly during the 24-h fermentation period. At the completion of the process, the treatment involving glucose exhibited the highest GABA concentration, reaching 164.95 mg/L, while the treatment without added sugar demonstrated the lowest concentration, at 132.68 mg/L. The organoleptic test revealed that the panelists preferred the fermented goat milk drink with added sucrose for color, aroma, viscosity, sour taste, and sweet taste. After a period of 5 weeks at a temperature of 4 °C resulted in a notable decline in GABA levels across all treatment groups. The concentration of GABA in the treatment with no added sugar was 105.34 mg/L, followed by the sucrose treatment (77.39 mg/L) and the glucose treatment, which exhibited the lowest concentration (71.33 mg/L). The total lactic acid bacteria (LAB) remained stable at a level of 109 CFU/mL, which continues to comply with the requirements of SNI 2981:2009 for yogurt quality, which stipulates a minimum of 107 CFU/mL. To further enhance sensory acceptance and GABA concentration, a more comprehensive study is necessary. HIGHLIGHTS In silico analysis has demonstrated that Lactiplantibacillus plantarum plantarum T-3 possesses the genes necessary for GABA biosynthesis. This includes the genes encoding GDH and GAD. The findings of this study demonstrate that GABA is produced from fermented Etawa goat milk inoculated with Lactiplantibacillus plantarum plantarum T-3. The GABA produced in this study is of a higher quantity than that previously observed in studies on GABA in fermented milk with no added MSG. The results of the organoleptic test demonstrated that the panelists exhibited a clear preference for the fermented Etawa goat milk drink that had been treated with sucrose sugar. This preference was attributed to the fact that the drink was perceived as containing a higher level of sweetness than the other types of sugar treatment. GRAPHICAL ABSTRACT