Use of hydration properties of proteins to understand their functionality and tailor texture of extruded plant-based meat analogues.

Different protein sources create distinct textures in plant-based meat due to differences in their hydration properties when exposed to different time, temperature, and shear regimes, which in turn depend upon their solubility, protein structure, and specific amino acids. This research aimed to identify these differences and manipulate them to reach a desired texture utilizing simple and reproducible analytical methods to characterize protein properties as either cold or heat swelling. Protein functionality was determined through least gelation concentration (LGC), water absorption index (WAI), and rapid visco analysis (RVA). Cold swelling or CS proteins (pea protein isolate, soy protein isolate, Arcon S soy protein concentrate) were characterized by an LGC < 14% and/ or WAI > 4.0 g/g, while LGC > 16% and/ or WAI < 4.0 g/g indicates proteins with heat swelling or HS properties (Arcon F soy protein concentrate, wheat gluten, and fava protein concentrate). An RVA peak time of around or less than 3 min (<75°C peak temperature) indicated CS properties while greater than 3.5 min (>80°C peak temperature) was considered HS. Protein mixes or treatments comprising mainly of different combinations and ratios of CS proteins were hypothesized to create a softer textured vegetable protein product or texturized vegetable protein (TVP) and those based on HS proteins a firmer TVP. Bulk density was higher for HS treatments (274-287 g/L) than for CS treatments (160-223 g/L). CS treatments exhibited a microstructure that was porous, while HS showed a dense, laminar microstructure. Texture profile analysis showed that CS treatments seemed to show a lower hardness (1154-1595 g) than the HS treatments (1893-2231 g). PRACTICAL APPLICATION: Controlling texture can be a valuable tool when producing a plant-based meat product. Different applications have various texture requirements. For example, a plant-based fish stick would require a softer texture than a hamburger or chicken nugget. By increasing the knowledge of how protein functionality affects meat analogue texture, the time needed to produce new products with novel textures can be reduced. Money could also be saved by being able to quickly replace ingredients with a more affordable or accessible protein with similar swelling abilities to preserve product quality.