Impact of protein ratio and thermal treatment on the aggregation and rheological properties of high-concentrated milk and pea protein suspensions

Abstract

The association of pea proteins (PP) with a more consumer-accepted product, such as milk, is considered as a strategy to improve plant protein consumption. This study investigates the physicochemical and rheological properties of mixed milk protein (MP): PP systems at different protein ratios (100:0, 80:20, 60:40, 40:60, 20:80, 0:100, MP:PP) in high-concentrated protein systems, before and after thermal treatment. The results showed that MP, represented by casein, and PP form independent networks with rheological behavior dependent on the major protein fraction involved in the mixture. However, a synergistic effect on elasticity and viscosity was observed for the 20:80 ratio, which was further accentuated by temperature and protein concentration increase. Also, the water dynamic was reduced after the thermal treatment, showing that in this ratio the casein, present in the milk proteins suspension is finely distributed within the PP network. These results bring new insights into the physical properties of composite plant/animal protein systems for the development of innovative mixed formulations.

Keywords: Aggregates; Heat-treatment; Milk protein; Mixed gels; NMR; Pea protein.