A Flexible Schema for the Valorization of Citrus Peels

Abstract

Large quantities of citrus fruits are eaten and processed in the Netherlands. Unfortunately, more than half of the fruit mass, including peel, pulp, and seeds, is discarded, often ending up in incinerators or landfills. Not only is this environmentally problematic, but it is also a waste of organic material that contains numerous valuable components. This review explores various pathways for the valorization of citrus peels that could be implemented at a fruit processing facility. The pathways are split into two sections: extraction and fermentation. The extraction section details the initial mechanical processing of the peels and outlines direct extraction techniques, with particular emphasis paid to subcritical water extraction and hydrodistillation. The fermentation section discusses the pros and cons of solid state and submerged fermentation and outlines some of the potential value-added products that could be obtained.