Modulating the consistency of water-in-oil high internal phase emulsions by fat crystals stabilization

Abstract

Justification: There is growing popularity in the development of food-grade emulsions due to their potential applications as fat replacers. One approach to fat replacement is via use of oil-continuous high internal phase emulsions (HIPEs), which consist of more than 74 v% dispersed water.Objectives: This research aimed to: i) develop water-in-oil (W/O) HIPEs stabilized by fat crystals, and ii) develop methods to tune HIPE consistency and stabilization against breakdown.Methods: The W/O HIPEs consisted of 80 wt% water, with the oil phase (20 wt%) consisting of 0 - 10 wt% of fully hydrogenated soyabean oil (HSO), and 8 wt% polyglycerol polyricinoleate (PGPR) present on an oil phase wt basis in soyabean oil. Microstructure (light microscopy), droplet size distribution (NMR), and viscoelasticity (strain-controlled rheometer) were evaluated after 24 h of storage at 5 °C. Results: HIPEs containing at least 3 wt% HSO were self-supporting soft solids, with the formation of clustered fat crystals contributing to their improved consistency. The average dispersed droplet size of all emulsions was ~ 4 µm, irrespective of the amount of added HSO. Although the rigidity of the HIPEs with 5 wt% or 10 wt% HSO was greatest, these HIPEs also demonstrated reduced stability against breakdown.Significance: This research showed that the consistency and resistance against breakdown of W/O HIPEs can be optimally modulated by adding low concentrations of HSO (0.5 or 1 wt%) to the continuous phase.