Partial replacement of whey proteins by rapeseed proteins in heat-induced gelled systems: Effect of pH

To enable opportunities in structuring food products based on the combination of plant and animal proteins it is important to understand the factors that influence the final product properties. The structural and rheological properties of heat-induced (95 degrees C for 20 min) gelled mixtures based on rapeseed proteins (RP) and whey proteins (WP) were studied at a total protein concentration of 10% w/w, at three mixing ratios (75:25, 50:50, 25:75) and pH of 7, 5 and 3 by differential scanning calorimetry, microstructural analysis and small deformation rheology. When RP and WP were mixed together at neutral pH they both contributed in gel network formation. In cases where RP modified the microstructural and/or denaturation properties of WP, synergistic mixed gels were obtained. The enhancement of the synergistic effect was affected by the protein mixing ratio and was dependent on the disparity of the modification exerted by RP. At acidic conditions when WP alone contributed to the gel network, addition of RP generally did not influence the inherent structural properties of WP gels and synergetic gels in most cases of mixing ratios were not formed. By mixing RP with WP various structures and rheological properties can be obtained at certain pH conditions and protein mixing ratios. This enhances opportunities in designing food products with novel properties different from the ones the individual ingredients can produce. (C) 2017 Elsevier Ltd. All rights reserved.