Fermentation Dynamics of Naturally Fermented Palm Beverages of West Bengal and Jharkhand in India

Abstract

The term ‘toddy’ represents a group of different varieties of mild-alcoholic palm beverages of coastal and inland India, produced from the fresh saps of various palm trees through uncontrolled natural fermentation. In this study, we analysed the successional changes of microbial abundances and various physico-chemical parameters during natural fermentation (0 h to 48 h) of taal toddy, prepared from Palmyra palm, and khejur toddy, prepared from date palm of West Bengal and Jharkhand in India. Microorganisms from different successional levels were isolated and grouped using repetitive element sequence-based PCR (rep-PCR) technique and identified by the sequencing of 16S rRNA gene and D1-D2 region of 26S rRNA gene for bacteria and yeasts, respectively. Enterococcus faecalis, Lactiplantibacillus plantarum, Lacticaseibacillus paracasei and yeast Saccharomyces cerevisiae were identified during natural fermentation of toddy. During the natural fermentation, the average pH and total sugar content in the samples of both taal and khejur toddy decreased, whereas a gradual rise was observed in the contents of acidity, total alcohol, total ester and total protein. Bio-active potential (presence of phenolics and flavonoids) of toddy was also analysed (0 h to 48 h), where contents of total phenolics, flavonoids and resulting anti-oxidant activity were found higher in the end-product than the fresh palm sap, indicating toddy as a functional low-alcoholic drink. Lastly, it can be concluded that the inter-variable dynamics and microbial interrelation, which in turn depend on a number of local factors, regulate the overall fermentation dynamics and determine the product quality.