Utilization of Diaphragma juglandis extract as a natural antioxidant for improving the oxidative stability of soybean oil during deep frying

Jia Chen; Lingyan Zhang; Qi Li; Yuan Gao; Xiuzhu Yu

doi:10.1016/j.fochx.2022.100359

Utilization of Diaphragma juglandis extract as a natural antioxidant for improving the oxidative stability of soybean oil during deep frying

Food Chem X. 2022 Jun 7:14:100359. doi: 10.1016/j.fochx.2022.100359. eCollection 2022 Jun 30.

Authors

Jia Chen¹, Lingyan Zhang¹, Qi Li¹, Yuan Gao¹, Xiuzhu Yu¹

Affiliation

¹ Engineering Research Center of Grain and Oil Functionalized Processing in Universities of Shaanxi Province, College of Food Science and Engineering, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi 712100, PR China.

Abstract

Lipid oxidation significantly shortens the life of frying oils, and this challenge can be addressed by using antioxidants. This work aimed to investigate the effect of Diaphragma juglandis extract (DJE) on the oxidative stability of soybean oil during deep frying. Tert-butylhydroquinone (TBHQ) and tea polyphenol (TP) were applied as positive controls. A total of 31 polyphenols were determined in DJE, and catechin, quercitrin, taxifolin, quercetin 3-β-d-glucoside, epicatechin, gallic acid, and 3,4-dihydroxybenzoic acid were the main components. The antioxidants effectively delayed the degradation of triglycerides and inhibited the increase in the contents of p-anisidine, oxidized triglyceride monomers, triglyceride dimers, and triglyceride oligomers, with DJE exhibiting better performance. Moreover, DJE showed better inhibitory effect on the formation of (E)-2-alkenals, (E,E)-2,4-alkadienals, 4-oxo-alkanals, primary alcohols, and secondary alcohols detected by ¹H nuclear magnetic resonance than TBHQ and TP. Therefore, DJE has great potential as an excellent antioxidant in large-scale industrial applications.

Keywords: AV, acid value; DJE, Diaphragma juglandis extract; Deep frying; Diaphragma juglandis; HPSEC, high-performance size exclusion chromatography; K232, conjugated dienes; K268, conjugated trienes; OxTGs, oxidized triglyceride monomers; Oxidative stability; PV, peroxide value; Phenolic extract; TAG, triglyceride; TBHQ, tert-butylhydroquinone; TGDs, triglyceride dimers; TGOs, triglyceride oligomers; TGPs, oxidized triglyceride polymers; TP, tea polyphenol; TPC, total polar compounds; p-AnV, p-anisidine value.