Protein based ingredients are a high priority within the strategic innovation program (SIP) Customised Processed Food. This program has been defined in 2015 to strengthen the innovation potential within the Netherlands by promoting collaboration between TNO and Wageningen FBR (WFBR). The previous Protein Functionality project has been completed and disseminated. In view of the successful outcome a follow-up project has been defined by the participating knowledge Institutes and industrial partners to further increase the innovation potential of protein based ingredients. The current project concerns activities that qualify as industrial research with private co-financing as described in the provided checklist.

The long-term aim of the industrial partners is to be able to better predict functionality of protein concentrates, isolates and hydrolysates containing a complex mixture of natural ingredients in a food product. In the previous project, we focused on textural functionality and storage stability of protein ingredients that may contain substantial amounts of impurities as a result of mild and sustainable purification strategies. It was found that these impurities do not always have a negative effect on the functionality of the proteins. In this new follow-up project we investigate methods to quantify/characterize protein-protein interactions in complex dairy protein mixtures (as such, mixed with hydrolysates, and mixed with plant proteins). These methods will allow investigation of the role of aggregation and its dynamics in relation to storage stability and digestibility. The project consists of two subprojects:

1. Protein-protein interactions and aggregation dynamics in protein mixtures;

2. Role of protein-protein interactions and aggregation on protein digestion kinetics.

Important part of the project is the development of a methodology to measure (initial) aggregation and predict shelflife stability of these protein mixtures. Therefore we will aim at quantifying protein-protein interactions and aggregation by various experimental techniques in combination with advanced multiscale modelling techniques. This will give important generic scientific insights in the relation between protein molecular properties and aggregation propensity and dynamics as well as on the role of other non-protein components. Furthermore, aggregation will be studied during in-vitro digestion. Various enzymes will be studied to control aggregation during shelf-life and/or during digestion. These learnings will allow industry to better predict the functionality of proteins in terms of generic measurable protein properties and thus better predict and control the stability and digestibility of their end products. This will result in higher product quality, less waste, and more flexibility in ingredient use. Increased ingredient

flexibility also allows industry to choose for more sustainable produced ingredients while maintaining the high quality of their end products.