Algarve's PGI citrus essential oils: unlocking the potential of food industry by-products

Worldwide, the processing of citrus juices generates elevated amounts of waste (around 120 million tons, annually), due to the discard of these fruits by-products, such as peels, seeds and pulp, leading to an unprecedented environmental burden. Portugal's citrus fruits cultivated under the Protected Geographical Indication (PGI) designation, particularly, constitute a significant agricultural sector, which resulted in a production of approximately 398.83 thousand tons, in 2019 [1]. Nevertheless, the processing of these citrus results in wasting between 45% and 50% of the fruit, and contributes to environmental issues such as water and land pollution [2, 3]. Orange (Citrus sinensis) and lemon (Citrus limon) peels, for instance, contain valuable bioactive compounds such as polyphenols, essential oils, and fiber, which can be repurposed for novel food, pharmaceutical and cosmetic applications [2,3]. Regarding these promising compounds, citrus peels essential oils (EO’s) have gained increasing attention for their diverse applications within the food preservation area, due to their properties, such as potential antimicrobial and antioxidant capacities [2,3]. Therefore, the repurpose of citrus by-products, particularly the essential oils extracted from their peels, presents a favorable solution for environmental challenges posed by excessive waste, bringing forward a valuable approach for innovative applications regarding the food industry, among other sectors. Objectives: The present work aimed the extraction and characterization of essential oils, from orange (Citrus sinensis) and lemon (Citrus limon) peels, using a sustainable approach based on green chemistry principles, in a way to valorize these bioactive compounds through potential food preservation applications, promoting circular economy within the industry.