The Influence of Lactobacilli in GABA and Amino Acid Profile of Fermented Mature Coconut Water

Mature coconut water (MCW) is a waste product from the coconut milk industry. It is sour and unpalatable, yet it contains sufficient nutrients for microbial growth. Four Lactic Acid Bacteria (LAB), namely L. acidophilus B0258, L. brevis VM1, L. casei B0189, and L. plantarum B0103 were used to ferment MCW over 120 h. Among these LAB strains, only L. casei was capable to grow well with the highest viable bacteria count of 1 x 1011 colony forming unit (cfu)/ml. Although all LAB produced α-aminobutyric acid (GABA) after fermentation, L. acidophilus and L. plantarum produced the highest amount of GABA with the increment of 35.4%±7.9 and 38.9%±1.7, respectively. Other amino acid profiles of fermented MCW were also investigated, but most of them were consumed by the LAB. Both L. acidophilus and L. plantarum utilized the most essential amino acids. Within the first 24 h, GABA content was enhanced in all LAB strains when they were actively growing. This study showed that both L. acidophilus and L. plantarum have great potentials to increase GABA content in MCW. Fermented coconut water can be formulated as a healthy functional drink as GABA is known to have therapeutic value in alleviating stress as reported by past research findings.