Synergistic functionality of transglutaminase and protease on modulating texture of pea protein based yogurt alternative: From rheological and tribological characterizations to sensory perception

Abstract

Although the general mechanism of transglutaminase (TGase) and protease on texturizing protein gels has been known, their synergistic functionalities on modulating the textural and sensory attributes of pea protein based yogurt alternative (PPBYA) are still not clear. In this work, 9 PPBYA gels treated by the mentioned enzymes were manufactured to investigate their texturizing functionality. By treating PPBYA milk (emulsion) with TGase (0.47 U/g protein), the resultant PPBYA gel had an increased strain resilience by ∼1.8-fold compared to blank control (γ-LVE); however, the brittleness of the gel was also increased by ∼4.8-fold (Index-FT). Co-application of TGase (0.47 U/g protein) and protease (0.1 U/g protein) seemed not to cause changes in some conventional rheological parameters as compared to the PPBYA control, for instance the referred parameters were strain resistance, hardness, and brittleness. However, the impact of mentioned synergistic enzymatic treatment on PPBYA gel may be clearly demonstrated by nonlinear rheological parameters; the Pipkin diagrams showed that co-application of TGase and protease resulted in PPBYA gels with higher homogeneity of dynamic rheology behavior in response to large deformation. Overall, the enzymatic treatments were able to result in significant changes in structure, rheology, tribology, and sensory attributes. Sensory textural attributes e.g. smoothness-in-mouth and astringency were both correlated with flow strain, whereas lubrication transition behavior was correlated with astringency. The obtained results demonstrated that the difference of textural characteristics between PPBYA and yogurt can be reduced by the co-application of TGase and protease at an optimized ratio and dosage rate.