Chapter 15 - Pretreatment of fruit and vegetable waste for the production of biofuels and high-value products

Abstract

Starting from production to human consumption, one-third of the food produced globally is wasted each year. Food waste (FW) generation not only causes economic loss in terms of resources used for its production but also involves several environmental challenges. Around 20% of waste out of 14 MMT (million metric tons) are produced during each step of processing of food to consumption. Compared to other food processing sectors, 25%–30% of waste are obtained from fruit and vegetable sector which includes peels, pulp, tuber, skin, seeds, shell and pomace. Approximately 55 MMT of waste is generated during each step of processing, which encompasses fruit and vegetable processing (5.5 MMT), wine processing (5–10 MMT), freezing and canning (6 MMT) and rest. Moreover, fruit and vegetable waste (FVW) generation rates are predicted to be increased by 49% by 2025 from 278 to 416 million tons in Asian countries. China is the largest producer of FVW while India ranked third. If these wastes are not treated properly, they can cause serious environmental hazards due to the emission of GHGs during decomposition. Therefore, to circumvent these issues, there is a need of an alternative strategy for effective waste management along with resource recovery. As FVWs are rich is carbohydrate, they can act as potential alternative feedstock for the production of biofuels and other high-value bio-based products. Several studies have been carried out using FVW as substrates to produce biofuels such as bioethanol, biobutanol, biohydrogen, biomethane, biohythane and biodiesel. Additionally, many studies have also been reported on their use for producing bioplastic, organic acids, enzymes, single-cell protein and biofertilizer. FVWs are also rich in many bioactive compounds such as carotenoids, flavonoids, vitamins and phenolic acids that can be effectively extracted by green technologies. Additionally, large-scale production of bio-based products from FVW in an integrated closed-loop approach will help in the reduction of adverse socio-economic and environmental impacts associated with the generation of FVW.