Stabilisation of oil-in-water emulsions with non-chemical modified gelatinised starch

Miroslaw M Kasprzak,William Macnaughtan,Stephen Harding,Peter Wilde,Bettina Wolf

doi:10.1016/j.foodhyd.2018.03.002

Miroslaw M Kasprzak, William Macnaughtan + Show 3 more

Open Access

https://doi.org/10.1016/j.foodhyd.2018.03.002

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Abstract

In this research, stabilisation of oil-in-water emulsions with non-chemically modified gelatinised starch is presented. Thus far only octenyl succinic anhydride (OSA) modified gelatinised starch has been known to adsorb at emulsion droplet interfaces, acting as emulsifiers. Screening a range of commercially available food starches revealed that a non-waxy rice starch, a waxy rice starch and the waxy maize starch PRIMA600 showed oil-in-water emulsifying ability following gelatinisation. The microstructure of emulsions formulated with 20% oil and 1% starch was stable for at least 3 months. Thermal, crystallinity and molecular property analyses as well as amylose and protein content revealed no obvious link to this property. Nevertheless, this research has provided the food industry with exciting results for the formulation of clean label emulsions. Moreover, it presents a concept for oral release food emulsions with destabilisation via salivary amylase digestion of the stabilising starch emulsifier.

Highlights

Emulsions are a frequently encountered microstructure in processed consumer goods including foods, paints and cosmetics
They were applied at a concentration of 1% to emulsify 20% of oil as it was already known that at this concentration, utilising the same process, the reference octenyl succinic anhydride (OSA) starch would stabilise o/w emulsions (Chiu et al, 2015)
Ability of the starches to stabilise the o/w emulsions was judged by assessing the emulsions in their storage vials one day after processing, see Fig. 1

Summary

Introduction

Emulsions are a frequently encountered microstructure in processed consumer goods including foods, paints and cosmetics. They are two-phase liquid dispersions where one phase is present in the form of droplets in another immiscible phase. In practice emulsion microstructures are kinetically trapped through the use of emulsifiers and often the addition of viscosity enhancers to the continuous emulsion phase. Emulsifiers adsorb at the interface between the two immiscible liquid phases imparting electrostatic or steric barriers between neighbouring and colliding droplets preventing coalescence. Adsorption occurs during processing, trapping process induced microstructures if the concentration of added emulsifier is high enough compared to the total interfacial area of the emulsion. Coalescence will occur until surface saturation traps the evolving microstructure. Viscosifiers aide the prevention of coalescence by slowing the creaming or sedimentation of individual droplets close proximity of droplets which may lead to coalescence

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