Relationship between a technofunctional property of food product and the physico-chemical and structural characteristics of peptides: An in silico approach

Food products are complex matrices. They may contain molecules from several families, which interact with themselves to generate structure and functionality. Among these molecules are proteins and peptides which may originate from protein hydrolysis, e.g. in cheese. It is still difficult to establish the relationship between a pool of peptides and their technofunctionalities such as emulsifying, foaming, gelling or even viscoelastic properties in a food matrix. The information usually known is the hydrolysis degree which informs on the average size of the peptides formed. A high hydrolysis degree induces the production of a peptide pool of small size (less than 20 amino-acids). Advances in identification methods render possible the identification of peptides that are present in the food matrix. From the peptide sequence, the peptide physico-chemical characteristics such as size, charge, hydropathy, aliphatic index, isoelectric point could be calculated as well as their secondary structure. The aim of this study was to determine which physico-chemical and structural characteristics of peptides are involved in the stretchability of cheese. From a previous study [1] on a fermented food product (Swiss-type cheese) for which one typical functionality criterion was measured (stretchability) and peptides were identified, we developed a methodology based on multivariate exploratory analysis such as Principal Component Analysis and Correspondence Analysis to establish a relationship between peptide characteristics and their technofunctional property. This method allowed us to determine that peptides predominantly involved in the stretchability of the cheese were amphiphilic and contained more than 15 amino-acids. It will be then possible to target enzymes able to produce peptides with chosen characteristics. This method can be applied to other types of peptides and other food technofunctionalities in other food matrices.