Onion (Allium cepa L.) peel: A review on the extraction of bioactive compounds, its antioxidant potential, and its application as a functional food ingredient

Abstract

Functional food development is rapidly increasing as a result of consumer consciousness concerning healthy and nutritious foods. In turn, research exploring novel ingredients for formulating functional foods has been accelerated.Onion peel or skin is a byproduct obtained from onion processing that contains abundant phytochemicals, contributing to its antioxidant potential. The main focus of this review is to highlight different extraction techniques (both conventional and nonconventional) that can be implemented to extract the bioactive compounds from onion peel and assess their antioxidant activity. Furthermore, this review highlights the major areas for the application of onion peel and its extract as prospective functional ingredients, thus aiding in the preparation of designer foods with additional health benefits. The use of onion peel could also assist in redesigning popularly consumed processed foods, such as baked products, noodles or pasta, as packaging material, meat quality improvers, colorants, and juice clarifiers. This review serves as a preliminary document that can assist in exploring different ways of incorporating bioactive onion peels or skin into the functional food industry and concludes that future research can assist in the effective and efficient utilization of this resource.

Antioxidant and Immune Stimulating Effects of Allium cepa Skin in the RAW 264.7 Cells and in the C57BL/6 Mouse Immunosuppressed by Cyclophosphamide

“…TPCs of red, white, and yellow onion extracts produced by methanol were 132 mg GAE/mL, 112 mg GAE/mL, and 120 mg GAE/mL, respectively [ 23 ]. OS was rich in quercetin, phenolics, and flavonoids, and these compounds have been reported with high antioxidant capacity [ 24 ]. Our result showed that the TPC in OS extract was lower than that in ethanol extract from OS [ 22 ].…”

A systematic review of black soybean (Glycine max (L.) Merr.): Nutritional composition, bioactive compounds, health benefits, and processing to application

“…Compared with YS, BS exhibits better antioxidant, anti‐obesity and hypolipidemic, anti‐inflammatory, and anti‐cancer effects, especially antioxidant effects mainly owing to its abundant anthocyanins. In this review, we specifically focused on the comparative health benefits of BS and YS, in contrast to previous reviews that focused solely on BS (Bhartiya et al., 2020; Ganesan & Xu, 2017; M. Kumar, Barbhai, Hasan, Dhumal, et al., 2022; M. Kumar, Barbhai, Hasan, Punia, et al., 2022; M. Kumar et al., 2023; Shabir et al., 2022).…”

Exploring the underutilized novel foods and starches for formulation of low glycemic therapeutic foods: a review

“…Bran, including cereal bran (i.e., rice, wheat, oat), millet bran of both major (jowar, pearl-, finger-millet bran) and minor millet (barnyard-, foxtail-, little-, kodo-, proso-millet bran) are also reported to be a rich source of fiber, antioxidants, phytochemicals and minerals by several investigations documenting their nutritional richness (13)(14)(15)(16)(17)(18)(19). Vegetable and fruit wastes also have ample quantity of fiber, vitamins, minerals and phytochemicals thereby exhibiting healthpromoting abilities (20)(21)(22)(23)(24).…”