Citrus By-Products: Valuable Source of Bioactive Compounds for Food Applications

Abstract

Citrus production produces about 15 million tons of by-products/waste worldwide every year. Due to their high content of bioactive compounds, several extraction techniques can be applied to obtain extracts rich in valuable compounds and further application into food applications. Distillation and solvent extraction continues to be the most used and applied extraction techniques, followed by newer techniques such as microwave-assisted extraction and pulsed electric field extraction. Although the composition of these extracts and essential oils directly depends on the edaphoclimatic conditions to which the fruit/plant was exposed, the main active compounds are D-limonene, carotenoids, and carbohydrates. Pectin, one of the most abundant carbohydrates present in Citrus peels, can be used as a biodegradable polymer to develop new food packaging, and the extracted bioactive compounds can be easily added directly or indirectly to foods to increase their shelf-life. One of the applications is their incorporation in active food packaging for microbiological and/or oxidation inhibition, prolonging foods’ shelf-life and, consequently, contributing to reducing food spoilage. This review highlights some of the most used and effective extraction techniques and the application of the obtained essential oils and extracts directly or indirectly (through active packaging) to foods.

Fortification of vegetable fat with natural antioxidants recovered by bergamot pomace for use as an ingredient for the production of biscuits

“…38 This extraction allows citrus waste to be converted into a source of value-added products to use in functional food as widely demonstrated in the literature. 39 The liquid extract showed a low pH of 3.31. In general, many foods are chemically acidified to hinder the growth of microorganisms, which cause contamination and loss of foodstuffs.…”

The Essential Oil of Citrus lumia Risso and Poit. ‘Pyriformis’ Shows Promising Antioxidant, Anti-Inflammatory, and Neuromodulatory Effects

“…This compound was not found to induce any mutagenic, carcinogenic, or nephrotoxic risk to humans [ 38 ]. It was registered as generally recognized as safe (GRAS) in the Code of Federal Regulations for its use as a synthetic flavoring agent and it is commonly used in several pharmaceutical, food, and cosmetic products, in addition to ecofriendly pesticides and insect repellents [ 39 , 40 ]. In fresh Citrus fruits, limonene is generally present in the D-isoform, its main active form [ 41 ].…”

“…In fresh Citrus fruits, limonene is generally present in the D-isoform, its main active form [ 41 ]. This isoform has several health and therapeutic properties, such as antioxidant, anti-inflammatory, anticancer, anti-asthmatic, anti-microbial, and anticholesterolemic activities, as well as neuroactive and neuroprotective properties [ 37 , 39 ]. This wide range of biological activities is probably due to its marked lipophilicity, which allows it to easily cross all biological membranes, including the intestinal and blood–brain barrier, through simple passive diffusion, providing a good bioavailability in the systemic circulation [ 41 ].…”

Recent advances and role of melatonin in post-harvest quality preservation of shiitake (Lentinula edodes)

“…Lemon essential oil, derived from citrus lemons, enhances food preservation and flavor due to its potent antioxidant and antimicrobial properties, demonstrating notable antibacterial and antioxidant capabilities when integrated into chitosan/zeaxanthin composite membranes at different concentrations ( 158 ). As a consequence, Agaricus bisporus aging was delayed, and postharvest quality was maintained by suppressing microbial growth and respiration ( 110 ).…”