Unlocking the potential of phenolic compounds recovered from lemon by-products

Introduction: Citrus fruits are one of the most widely cultivated fruit crops and one of the most important products consumed in the Mediterranean region. The annual production of different types of citrus fruits was around 143 thousand tonnes in 2019, with lemons and limes accounting for around 20 thousand tonnes [1,2]. Industrial processes use only 45% of the total weight of the fruit, leaving a significant amount of waste, including peel (flavedo: 27%), pulp (albedo and endocarp: 26%) and seeds (2%) [3]. Lemon by-products are composed of significant amounts of bioactive compounds such as minerals, carotenoids, vitamins, essential oils (EOs), phenolic compounds (PCs) and fibres, which give them bioactivities related to food preservation, such as antimicrobial and antioxidant. These by-products can be explored to produce bioactive and functional ingredients to promote the zero-waste concept. Objectives: The objective of this work was to apply an integrated process to valorize lemon by-products of Algarve cultivars (Eureka variety) that are unattractive to customers. The application of an integrated process demonstrates the promising circular economy approach and allows the production of an extract rich in phenolic compounds. The recovered phenolic compounds show the potential to develop solutions for food preservation. Main conclusions: The valorization of citrus processing by-products, such as the phenolic compounds found in the Algarve's lemon by-products, represent promising sustainable food preservation solutions with antioxidant and antibacterial properties. This study also underlines the importance of turning waste into valuable resources in the global citrus industry, as a circular economy approach.