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

Abstract

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.