Plant-based high internal phase oil-in-water emulsions (HIPEs) are promising fat replacers. However, producing stable HIPES with improved viscoelastic properties is a challenge for the food industry. Conjugation of plant proteins, such as lupin protein isolate, with phenolic compounds, such as proanthocyanidins from grape seed extract, associated (or not) with moderate heat treatment arise as potential methods to tune the surface properties of proteins and, consequently, the droplet-droplet interactions that drive the viscoelastic properties of HIPEs. In this way, unheated (UHC) and heated (85°C, 15 min) (HC) lupin protein (LPI)-grape seed extract (GSE) conjugates were produced and used to stabilize high internal phase oil-in-water emulsions. Evaluation of stability by Turbiscan and oil loss by centrifugation over 56 days of storage did not reflect the kinetic stability of HIPEs against process conditions. Under shearing, UHC-stabilized emulsions at high GSE concentrations showed oil release, whereas all HC-stabilized HIPEs released oil. However, the increase in GSE concentration and heat treatment improved the viscosity and storage modulus (G’) of HIPEs, possibly due to the droplet-droplet interaction originating from hydrophilic and hydrophobic interactions in UHC and HC-stabilized HIPEs, respectively. This pivotal study confirmed that conjugation of a plant protein with GSE and heat treatment could improve the viscoelastic properties of high internal phase oil-in-water emulsions and produce HIPEs with superior texture (higher G’).

Consumers are becoming aware of the relevance of eating low levels of trans and saturated fats in processed foods. In addition, many countries are adopting regulatory measures on the use of these ingredients. For this reason, the exploration of new technologies capable of producing structures that trap liquid oil (composed of unsaturated fatty acids, considered healthier) has been widely investigated in order to replace saturated and trans fats in food products. One of the most promising technologies is the so-called oleogels, which present a great challenge to mimic sensory attributes related to the texture of processed foods based on saturated fats. In this review, we discuss how the different approaches used in the production of oleogels, direct or indirect methods, as well as compositional variables, such as oleogelators and mixing ratio, can directly influence the mechanical properties of these structures. An overview of the parameters that can interfere with these properties contributes to a better understanding of the building of the oleogels and their possible applications.