An advance on nutritional profile, phytochemical profile, nutraceutical properties, and potential industrial applications of lemon peels: A comprehensive review

Background: The last decade witnessed the rapid increase in the population worldwide, which fueled the development of food processing industry for fulfilling the daily demand for diversified food products. A massive amount of food by-products is simultaneously generated during the food processing. Generally, these by-products are discarded as food waste that results in adverse impacts on the environment and economics. Lemon peels are the main by-products generated by lemon processing. However, lemon peels contain abundant high value-added substances that demonstrate desirable nutraceutical properties and promise in industrial application. Scope and approach: The review comprehensively summarizes the nutritional profile, phytochemical profile, nutraceutical properties, and potential application into food industry, bioremediation, and aquaculture. Key findings and conclusions: Lemon peels are rich in nutritional substances, especially vitamin C, pectin and fibers, and phytochemical compounds with desirable properties predominantly comprising phenolic constituents and essential oils, which supported the potential industrial applications. It has been demonstrated that lemon peels hold great nutraceutical effects, including antioxidant, antimicrobial, antidiabetic, anti-obesogenic, lipid-lowering, anti-colitic, anti-arthritic, anti-urolithic, anti-fatigue, ameliorating disuse muscle atrophy, skin pro-tection, and prebiotic properties. Lemon peels show great promise in the applications into food industry, including: 1) food ingredients with nutritional, antioxidant, and antibacterial properties; 2) film matrixes or active constituents for food packaging or edible coatings. Moreover, the application into bioremediation as re-movers for heavy metals and dyes and into aquaculture as beneficial constituents of fish diet is also promising.