Structuring Vegetable Oils Through the Formation of Capillary Suspensions: Comparison of Wheat Middlings and Pure Cellulose Processed by High-pressure Homogenization

Reducing the intake of harmful trans-fats and saturated fats in the diet, by replacing detrimental fats with healthier oils, without affecting the organoleptic properties of the food product, represent a formidable challenge for the scientific community. In this scenario, this work explores a possible strategy for structuring sunflower oil by investigating the formation of capillary suspensions using wheat middlings (WM) and pure cellulose (CL) as a structuring solid fraction. High-pressure homogenization (HPH), a purely mechanical cell disruption technology, was directly applied to oil suspensions of WM or CL. Subsequently, the addition under high-shear mixing (HSM) of different amounts of an immiscible secondary fluid, water, to the oil suspensions, led to WM and CL particles bridging and network formation, through the development of attractive capillary forces among the particles. The effect of water and particles characteristics on the rheological behavior of the oil suspensions was investigated. The presence of water caused initially an increase in viscosity and then a decrease, as water concentration exceeded a critical value, with an inversion from a continuous oil phase to a continuous aqueous phase. Moreover, the oxidative stability of the capillary suspensions was evaluated, during accelerated aging. The proposed approach not only does not suffer the presence of water, but significantly improves the oxidation stability with respect to the pure oil.