Extrusion and physicochemical properties of soy-whey protein meat analog

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Soy and whey proteins are two finest proteins due to their nutritional and health benefits. To reap these benefits it is essential to use them in products that are palatable and readily acceptable by consumers such as fibrous meat analogs. The objective of this study was to investigate the extrusion performance of soy, whey protein blends and to evaluate the effect of process variables on extruder responses, physical and chemical properties of resulted texturized product. A 4 [multiply] 3 [multiply] 3 factorial experimental design with two replications was used. It includes four feed compositions with WPI/SPI ratios (0/60, 10/50, 20/40, 30/30) (w/w), wheat gluten and wheat starch kept at 35% and 5%, respectively, three moisture levels (50, 55, and 60%), and three cooking temperatures (165, 170 and 175[degree sign]C). Whey protein isolates (WPI), moisture content, and their interactions had significant effect on extruder responses, hardness, chewiness and the lightness of the product (P [lesser than or equal to] 0.05). Cooking temperature had significant effect (P [lesser than or equal to] 0.05) only on extruder responses. WPI and moisture content had significant (P [lesser than or equal to] 0.05) effect on protein solubility in all solvents except in PBS + 8 M Urea + 0.1% 2-Me. Raising the percentage of WPI (0-30%) and/or moisture from 50-60% in the feed resulted in lower die pressure, softer texture, less fiber formation and lighter color. Degree and length of fiber formation was severely affected by raising the WPI (%) and it was not observed at 30% level.