Octenyl succinate esterified gum arabic stabilized emulsions: Preparation, stability and in vitro gastrointestinal digestion

Abstract

Octenyl succinate esterified gum arabic (OSGA) with degree of substitution of 1.6% was successfully synthesized. Structural changes from the octenylsuccinylation of Arabic gum were investigated by FT-IR. The emulsifying ability of OSGA was studied by comparing with whey protein isolate (WPI) and sodium starch octanoyl succinate (OS-st). The minimum concentration of OSGA, WPI and OS-st to stabilize emulsions with 20% oil phase was 0.6%, 0.4% and 0.8%, respectively. The average droplet size of 0.8% WPI, OSGA and OS-st stabilized emulsion was 280, 484 and 929 nm, respectively. All these three emulsifiers exhibited reduced emulsifying ability at acidic conditions. But all the emulsions had excellent stability under alkaline conditions. Unlike the other two emulsifiers, OSGA stabilized emulsions maintained great stability at high temperature and ionic strength conditions. Emulsions formed by OSGA remained stable at heating temperature up to 90 °C and ionic strength up to 500 mM. The final extent of lipid digestion in emulsion stabilized by OSGA was 53%, which was similar to that of OS-st stabilized emulsion and smaller than that of WPI stabilized emulsion (75%). This research provides strong evidence for wide application of OSGA in emulsion food products, especially in some food containing high salt or requiring high temperature treatment.