Fermentation of coconut water by probiotic strains Lactobacillus acidophilus L10 and Lactobacillus casei L26

Coconut water is becoming an increasingly popular beverage and sports drink in tropical countries due to its high mineral content. Probiotic fermentation of coconut water would provide consumers with a novel probiotic beverage which can provide both hydration and probiotic benefits. The aim of this study was to assess the growth, survival and fermentation performance of two probiotic bacteria in coconut water. Lactobacillus acidophilus L10 and L. casei L26 grew well in coconut water and showed similar growth patterns. The viable cell count of the two probiotic cultures reached approximately 108 CFU/ml after 2 days fermentation at 37 °C and maintained approximately107–108 CFU/ml after 26 days at 4 °C. Changes in total soluble solids (oBrix), pH, sugars, organic acids and minerals were similar between the two probiotic cultures, except for fructose, glucose, copper, phosphorus and lactic, acetic and malic acids. There were significant variations between the two cultures in their ability to produce and consume these compounds. L. acidophilus produced higher amounts of 2-heptanone, 2-nonanone, benzaldehyde, 2-heptanol, 2-nonanol, δ-octalactone and δ-dodecalactone, whereas L. casei produced higher amounts of acetic acid, diacetyl, acetoin, δ-decalactone, 3-methyl-3-buten-1-ol, linalool, 1-octanol, p-tolualdehyde and ethyl 2-hydroxypropanoate. There was no substantial change in mineral content. These results suggest the feasibility of fermenting coconut water into a probiotic beverage, especially for sports nutrition, with the dual benefits of electrolytes and probiotics.