Valorization of pomelo (Citrus grandis Osbeck) peel: A review of current utilization, phytochemistry, bioactivities, and mechanisms of action

Abstract

Citrus grandis Osbeck, commonly known as “pomelo” or “shaddock,” is the largest citrus fruit, the peel of which is a well‐known agricultural residual waste. Pomelo peel offers a wide range of components such as essential oils, polysaccharides, and phytochemicals with potential food applications. Utilization of pomelo peel to recover these components is an important step toward agricultural sustainability. This review covers pomelo peel utilization opportunities beyond conventional composting and animal feed production, and critically examines value‐added uses via the recovery of potentially bioactive components. The peel of pomelo accounts for approximately 30% of the total fruit weight and contains phytochemicals, including aroma‐active volatiles, pectin, flavonoids, phenolic acids, carotenoids, coumarins, and polysaccharides. Recovery of these phytochemicals offers an opportunity for value‐added utilization such as the development of enriched or functional foods and nutraceuticals. The health‐promoting and therapeutic potential of pomelo peel extracts and isolated pure compounds have been evaluated through numerous in vitro and in vivo studies that revealed a wide range of bioactivities, including hypolipidemic, hypoglycemic, antioxidant, antimicrobial, anti‐inflammatory, and anticancer effects. Preclinical evidence highlights multifaceted molecular and signaling events that possibly underlie the said bioactive potential. Overall, the pomelo processing industry offers a great opportunity to recover or produce valuable products from the large amounts of residual wastes it generates. It is envisaged that a thorough understanding of the bioactive components of pomelo peel, their functional and nutraceutical applications, and mode of actions will benefit the food industry.

Efficacy and sustainability of natural products in COVID-19 treatment development: opportunities and challenges in using agro-industrial waste from Citrus and apple

“…Citrus agro-industrial waste management has been encouraged since the waste can cause several environmental problems, such as the severe reduction in soil fertility due the presence of alkalis, antimicrobial compounds, and organic matter with low nitrogen content (which difficult microbial decomposition) [ 102 ]. The administration of Citrus wastes is such an important issue that as juice commercialization increases, several researches have been performed to develop methods to afford the creation of value-added products 98 , 103 .…”

“…The most valorized metabolites obtained from apple pomace include pectin, chlorogenic acid, ursolic acid, and glycosylated flavanones, flavanone, flavones, and flavanols. Interestingly, the major occurrence of flavanones in apple pomace are as naringenin and hesperetin, [ 103 ] as previously mentioned, compounds with great potential as anti-COVID-19 metabolites. With the large concentrations of naringenin (up to 75.6 mg kg -1 of dry weight), hesperetin (up to 676 mg kg -1 of dry weight), [ 103 ] and ursolic acid (average of 400 μg g -1 of fresh weight) [ 94 ] in apple pomace, this residue can be a reliable source, not only to isolate those compounds, but also to create bioactive extracts.…”

Production of Sucrolytic Enzyme by Bacillus licheniformis by the Bioconversion of Pomelo Albedo as a Carbon Source

“…The high carbohydrate ratio, especially the soluble sugar could make the pomelo albedo an attractive carbon source for microbial fermentation. Currently, bioethanol production is the primary commercial operational process that utilizes pomelo peel waste as a raw material [51,52]. The potential of pomelo albedo in the manufacture of value-added products such as enzymes is not yet fully explored.…”

Evaluation of Carotenoids Accumulation and Biosynthesis in Two Genotypes of Pomelo (Citrus maxima) during Early Fruit Development

“…[ 20 , 21 ]. Pomelo peel extracts and isolated pure compounds also have a wide range of biological activities [ 22 , 23 , 24 , 25 ]. The epidermis of young pomelo fruit is dark green, the juice vesicle is not yet developed.…”