Lemon (Citrus limon) Bio-waste: Chemistry, Functionality and Technological Applications

Citrus genus, which includes important species of lime, lemon, grapefruit, tangerine, mandarin, and orange, is one of the largest fruit crops in the tropical and subtropical parts of the world. Lemon (Citrus limon) is a flowering plant that belongs to the genus citrus and the Rutaceae family. A percentage of 2.5 million tons of lemon production is addressed for processing. One of the most critical concerns in citrus processing industries is the management of citrus solid waste, typically constituted of the peel, seeds, and leaf residues remaining after the juice extraction process. These inexpensive by-products can be processed to obtain food and no-food products: valuable nutrients, such as fibers, vitamins, essential oils, minerals, and biologically active compounds, mainly phenolics and carotenoids. A shot of an integrated approach of lemon waste valorization following the traditional approach and the biorefinery one is described and discussed. Various food industries are trying to use these bioactive molecules obtained from such wastes to produce compounds with therapeutic potentials or make nutritional supplements for nutrition and health using waste management techniques. Among these, bioactive compounds extracted from lemon waste have valuable therapeutic properties, the chemistry and therapeutic function of which will be examined in this chapter.