Pressure-induced gelation of blended milk and pea protein suspensions

Abstract

The pressure-induced (400 MPa for 15 min) gelation of blended skim milk (SMP) and pea protein concentrate (PPC) suspensions (15% w/w) at different ratios (SMP:PPC = 10:0, 8:2, 6:4, 5:5, 4:6, 2:8, 0:10) were studied. Blending milk and pea proteins reduced the gel strength markedly, indicating that milk and pea proteins do not interact with each other to the same extent. The secondary structure of the proteins was not significantly changed after HP treatment. The PPC dominating gels (0:10 and 2:8) had a large increase in surface hydrophobicity indicating higher exposure of hydrophobic clusters. Based on a differential solubility method it was established that the SMP dominating gels are govern mostly by electrostatic and hydrophobic interactions, while disulphide bonds, hydrogen bonds and electrostatic interactions contributed most to the PPC dominating gel networks. The weak 5:5 gel was established solely by hydrophobic interaction between milk and plant proteins. It is suggested that in the milk protein dominant gel (8:2), the milk proteins formed the primary gel structure likely filled with the pea protein secondary gel network and/or aggregates, whereas the inverse occurred in the pea protein dominant gel (2:8). Replacing milk proteins with pea proteins offers a great potential for produce innovative dairy products using high pressure processing, like for example dairy desserts with a neutral pH and textural properties similar to yogurt.