Freeze–thaw stability of edible oil-in-water emulsions stabilized by sucrose esters and Tweens

Abstract

This work aimed to investigate freeze thaw stability of 20 wt% coconut oil (CtO) and corn oil (CnO)- in-water emulsions stabilized by 1 wt% of various types of sucrose esters and Tweens. Sucrose esters composed mainly of sucrose monostearate (S1670), sucrose monopalmitate (P1670), sucrose monolaurate (L1695), Tween 20 (TW20), Tween 60 (TW60), and Tween 80 (TW80) were used. After all emulsions were frozen at 20 ± 2 C and thawed to room temperature, their stability was analyzed from visual appearance, optical micrographs, amounts of destabilized oil, and average particle sizes. The CtO emulsions stabilized by S1670 and P1670 were very stable, the CtO emulsions stabilized by L1695 partly destabilized, and the CtO emulsions stabilized by TW20, TW60, and TW80 mostly destabilized into oil layers separated on top. The excellent stability of CtO emulsions stabilized by S1670 and P1670 was also confirmed from similar thermograms obtained from differential scanning calorimeter after three cooling–heating cycles (40 C to 40 C to 40 C at 5 C/min). It was proposed here that S1670 and P1670 affected the interfacial fat crystallization and their interfacial layers protected CtO emulsions against partial coalescence. Differently for the case of CnO emulsions, the CnO droplets remained liquid during freezing. All CnO emulsions stabilized by any emulsifiers destabilized by coalescence since these small surfactants could not provide enough interfacial barriers.