Effects of FeII, tannic acid, and pH on the physicochemical stability of oil body emulsions. (15th March 2023)

• Record Type: Journal Article
• Authors: Liao, Yi; Sun, Yufan; Kang, Mengxue; Zhong, Mingming; Wang, Shuai; Wang, Zhenxiao; Qi, Baokun; Li, Yang
• Is Part Of: Lebensmittel-Wissenschaft + Technologie =. Volume 178(2023)
• Publication Date: 2023-03-15
• Subjects: Oil body -- Tannic acid -- Antioxidant -- Pro-oxidant -- Oxidation stability; Food industry and trade -- Periodicals; Food -- Composition -- Periodicals; Microbiology -- Periodicals; Nutrition -- Periodicals; 664.005
• DOI: 10.1016/j.lwt.2023.114609
• Languages: English
• ISSNs: 0023-6438

Abstract

Abstract: This study examined the effects of solution pH (3.0, 5.0, and 7.0), Fe II, and tannic acid (TA) on oil body (OB) emulsions and monitored changes in emulsion particle size, zeta potential, appearance, microstructure, and oxidation stability over 14 days of storage at 37 °C. The chelation efficiency, zeta potential, and fourier-transform infrared spectroscopy results showed that the ability of TA to chelate Fe II and the absolute charge of TA-Fe complexes increased with the pH. In addition, the distribution of these complexes in the emulsions was influenced by their electrostatic and hydrogen bonding interactions with the OB. At pH 3.0 and 5.0, the TA-Fe and OB emulsion particles attracted each other, resulting in droplet flocculation. At pH 7.0, the TA-Fe and OB emulsion particles carried the same (negative) charge, and had little effect on physical stability of OB emulsions. TA generally inhibited the oxidation of OB emulsions but promoted the concentration of the primary and secondary oxidation products (61.48 mmol/kg and 50.5 μmol/kg, respectively) of Fe II -containing emulsions at pH 3.0. The obtained results provide new insights into the efficacy of TA as a natural antioxidant for emulsified foods and thus pave the way to increasing their quality and shelf life. Highlights: The metal chelating efficiency of TA increased with pH. TA-Fe complexes and OB exhibited electrostatic and hydrogen bonding interactions. Fe 2+ and a few chelates could migrate to the OB interface at pH 3.0 and 5.0 Most of the TA-Fe was distributed in the aqueous phase of OB emulsions at pH 7.0 TA exhibited both pro-oxidant and antioxidant activities in OB emulsions.