Effects of Hydrocolloid Type and Mixing Temperature on the Properties of Pea-Based Texturized Vegetable Protein Burgers

Given the growing interest in alternatives to cellulose-derived hydrocolloids, this study evaluated the effects of psyllium compared with methylcellulose (MC), hydroxypropyl methylcellulose (HPMC), and their combination on the functional and rheological properties of pea-based texturized vegetable protein (TVP) and the technological properties of the corresponding plant-based burgers. The influence of mixing temperature (5–25 °C) was also investigated. Hydrocolloid addition had limited effects on water solubility and oil absorption, whereas psyllium addition resulted in lower water absorption capacity, and the hydrocolloid mixture increased foaming capacity and stability of the tested pea-based TVP system. Viscosity was significantly affected by temperature and hydrocolloid type, while torque depended mainly on hydrocolloid type and its interaction with temperature. Before cooking, burger hardness was primarily influenced by mixing temperature, whereas after cooking, it was mainly affected by hydrocolloid type. Psyllium-containing burgers showed comparatively lower cooked hardness at 10 and 15 °C, while MC- and HPMC-containing burgers showed higher cooked hardness. Cooking loss was influenced by temperature, hydrocolloid type, and their interaction, with MC showing marked temperature-dependent behaviour and the hydrocolloid mixture providing the lowest losses at 15 °C. Overall, hydrocolloid functionality depended on hydration conditions, mixing temperature, and subsequent thermal treatment, and no formulation showed consistently superior performance across all technological properties.