Barley-Based Non-dairy Alternative Milk: Stabilization Mechanism, Protein Solubility, Physicochemical Properties, and Kinetic Stability

Abstract

This study investigated the technological properties of barley hydrocolloids to produce a kinetically stable plant-based non-dairy alternative milk. The impact of mechanical extraction assisted by electrolysis treatments (0, 5, and 15 V) on the barley protein content was examined. The protein-rich barley aqueous extract was used to emulsify canola oil enriched with vitamin D at different pH conditions (5, 5.6, 6, and 7) and temperatures (30 and 60 °C). The homogenization treatment performed at 60 °C allowed higher protein solubilization and better kinetic stabilization than the one obtained at 30 °C. This temperature probably promoted water retention in barley’s hydrocolloids and protein agglomeration, producing samples with larger Sauter mean diameters of ~ 14 µm and higher apparent viscosities from 13 to 16 mPa s. The rise in pH from 5 to 7 increased the electrostatic charges of the samples. In contrast, the pH decrease allowed a higher reduction in the interfacial tension between barley aqueous extract and canola oil up to 3.2 mN/m at pH 5. Despite these electrostatic and steric forces provided by the barley hydrocolloids, the beverage only showed better kinetic stability after the homogenization treatment at 60 °C. Therefore, the barley hydrocolloids acted as structuring agents in the production of barley-based non-dairy alternative milk, contributing to its kinetic stability by high internal phase Pickering emulsions.

Graphical Abstract