Zero-waste valorization of agricultural products: the model case of mixed fermentation in kombucha

The augmented cultivation and processing of horticultural crops, coupled with insufficient handling techniques and infrastructure, have culminated in a massive accumulation of fruit and vegetable waste. This phenomenon presents challenges in the scope of environmental concerns, food safety, and the increasing global population. Nonetheless, this waste holds diverse biological compounds and materials, thereby offering potential for valorization within the Circular Economy framework. This review delves into various potential valorization methodologies of fruit and vegetable waste, starting with the production of kombucha by mixed fermentation processes as a versatile and economically viable means of biotransforming organic matter. The review explores subsequent valorization methods of the bacterial cellulose produced during fermentation and the plant remains collected after the production of the drink. Along the process, we tackle the important task of achieving zero-waste in fruit and vegetable waste management. The review also highlights that succeeding in this practice requires the establishment of cross-sector partnerships enabling one sector to take advantage of the waste generated by another.