Effects of Extrusion on Protein Textures of Hydrolysed Rice and Pea Isolates

The structure and texture of plant proteins play a key role in determining their functionality and use in plant-based meat analogues. Extrusion is an effective technology for developing textures through protein denaturation and alignment, so controlling parameters such as die size is essential, as it determines the pressure, flow and final structure of the product. Conventional meat production faces environmental challenges such as deforestation, greenhouse gas emissions, and high resource use, reinforcing the need for sustainable protein alternatives like plant proteins. The objective of this study was to determine the effect of different nozzle diameters (1 mm and 3 mm) and types of hydrolysed protein isolates (pea and rice) during the extrusion process affect the physicochemical and nutritional parameters of textured proteins. The results indicate that both die diameter and the type of hydrolysed protein isolate significantly influence texturisation. The 1 mm die, by generating higher temperatures and pressures, produces less moist and tougher textures, without achieving the desired fibrous texture. In contrast, the 3 mm die results in moister products with better textural properties, and both showed lower protein losses with the 3 mm nozzle. Moreover, hydrolysed pea protein isolate showed superior textural characteristics and greater water and fat retention. Finally, the combination of the 3 hydrolysed pea protein isolates proves to be the most efficient.