Effects of different polarity of onion skin extracts on antioxidative properties and non‐volatile profiles. (29th April 2022)

• Record Type: Journal Article
• Authors: Hong, JiHee; Lee, YoonHee; Kim, Mi‐Ja; Lee, JaeHwan
• Is Part Of: International journal of food science & technology. Volume 57:Number 7(2022)
• Page Start: 4528
• Page End: 4536
• Publication Date: 2022-04-29
• Subjects: Antioxidant activity -- chemical profile -- lipid oxidation -- matrix -- onion skin -- solubility; Food industry and trade -- Periodicals; 664
• DOI: 10.1111/ijfs.15789
• Languages: English
• ISSNs: 0950-5423

Abstract

Summary: Onion skins are agricultural by‐products that contain high levels of antioxidants, including quercetin and protocatechuic acid. The solubility of extracts can affect their antioxidant capacity in food oil matrices. The antioxidative properties of onion skin extracts with different polarity were compared and the chemical profiles of the extracts were identified by GC‐MS. Highly lipophilic, moderately hydrophilic and highly hydrophilic onion skin extracts (HLE, MHE and HHE, respectively) were prepared and their antioxidant properties were tested using in vitro assays and bulk oil or oil‐in‐water (O/W) emulsions. The most abundant phenolic compounds in the onion skin extracts were quercetin and protocatechuic acid. The lipophilicity levels of HLE, MHE and HHE were 0.674, 0.394 and −1.225, respectively. HLE showed higher antioxidant capacity in bulk oil and O/W emulsion matrices compared to MHE and HHE. The antioxidant capacity of HLE was higher in the O/W emulsion than in the bulk oil system. Therefore, highly lipophilic onion skin extracts can be used as effective natural antioxidants in oil matrices, especially O/W emulsions. Abstract : Highly lipophilic, moderately hydrophilic, and highly hydrophilic onion skin extracts (HLE, MHE, and HHE, respectively) were prepared. HLE had the weakest red color and higher antioxidant capacity than other extracts. The most abundant phenolic compounds in the onion skin extracts were quercetin and protocatechuic acid. HLE retarded lipid oxidation effectively in oil‐in‐water emulsion compared to bulk oil matrix.