Citrus Waste Valorisation Processes from an Environmental Sustainability Perspective: A Scoping Literature Review of Life Cycle Assessment Studies

Citrus fruits and related processed products represent a major agricultural sector worldwide, contributing to food supply chains and to regional economies, particularly in Mediterranean and subtropical areas. Citrus processing generates significant amounts of post-processing waste, and their sustainable management is a critical challenge, driving growing scientific interest in exploring environmentally sustainable and profitable valorisation strategies. This study aimed at mapping the sustainability of post-processing citrus valorisation strategies documented in the scientific literature, through a scoping literature review based on the PRISMA-ScR model. Only peer-reviewed studies in English were selected from Scopus and Web of Science; in detail, 29 life cycle assessment studies (LCAs) focusing on the valorisation of citrus by-products have been analysed. Most of the studies were focused on essential oil extraction and energy production. Most of the biorefinery systems and valorisation aims proposed were found to be better than the business-as-usual solution. However, results are strongly influenced by the functional unit and allocation method. Economic allocation to the main product resulted in better environmental performances. The major environmental hotspot is the agrochemicals required for crop management. The analysis of LCAs facilitated the identification of valorisation strategies that deserve greater interest from the scientific community to propose sustainable bio-circular solutions in the agro-industrial and agricultural sectors.