Pulsed electric field-assisted fermentation: a novel approach for the kombucha production

Kombucha is a globally popular fermented beverage valued for its health-promoting properties, yet its traditional production is often hindered by slow and inconsistent fermentation kinetics. Non-thermal technologies, such as low-intensity Pulsed Electric Fields (PEF), offer a promising strategy to stimulate microbial activity without compromising product quality. This study investigated the application of low-intensity PEF to stimulate and accelerate kombucha fermentation. Seven PEF treatment conditions were screened to identify optimal parameters for inducing reversible electroporation in the Symbiotic Culture of Bacteria and Yeast (SCOBY). The most promising condition (1.14 kV/cm, 100 pulses, 17.78 kJ/kg) was evaluated over a 14-day period against an untreated control. Results demonstrated that optimised PEF treatment significantly accelerated microbial proliferation, with lactic acid bacteria and yeast counts reaching up to 2.5 log units higher than the control during early fermentation. This enhanced metabolic activity drove accelerated substrate utilization, resulting in a threefold increase in acetic acid and a 2.9-fold increase in ethyl acetate by day 14. Furthermore, PEF treatment positively modulated the volatile organic compound profile by enriching fruity esters and extending the enzymatic biotransformation of tea-derived polyphenols, preserving the beverage's high antioxidant capacity. In conclusion, low-intensity PEF serves as a promising lab-scale, precision tool capable of significantly modulate specific fermentation kinetics (sugar consumption and key metabolites production) while modifying its aromatic profile and preserving its nutritional and functional attributes.