Valorization routes of citrus waste in the orange value chain through the biorefinery concept: The Argentina case study

Abstract

Orange peel waste (OPW) creates challenges regarding environmentally sustainable disposal and potential valorization. Argentina is a major Citrus sp. fruit producer in Latin America. A share of the OPW is used to produce a colloid stabilizer in the beverage industry. However, large amounts of this waste are disposed of in landfills, reducing the orange value chain sustainability. The OPW chemical composition would allow the generation of valuable sub-fractions by applying different upgrading pathways. This review is addressed to summarize the most current and important pathways to upgrade OPW by applying the biorefinery concept. Moreover, this paper highlights the importance of the chemical composition when defining valorization routes. Polyphenols were identified as the most promising and reliable option to increase the sustainability of the orange industry. Then, an overview of extraction conditions, and extracted molecules is included. Biocatalysis is highlighted as a promising way to upgrade polyphenols in other added-value products. A case study is analyzed considering further processing of OPW produced by the citrus agroindustry in Argentina. The case study is related to the design and simulation of a biorefinery addressed to produce juice, essential oil, peel juice, polyphenols, and biogas. The case study is analyzed involving yields and economic performance demonstrating the high potential of essential oil, polyphenols, and biogas as promising products in a near future. As practical implications of this study, an analysis of different pathways to upgrade OPW is given. Moreover, the present study reinforces the chemical characterization as a crucial step before selecting upgrading pathways.