Effect of high pressure homogenization (HPH) on functional and rheological properties of hazelnut meal proteins obtained from hazelnut oil industry by-products

The effect of high pressure homogenization (HPH) on functional and rheological properties of hazelnut meal proteins was investigated. Hazelnut meal proteins were extracted from hazelnut oil industry by-products. Protein patterns remained unchanged up to 75 MPa, and band intensity decreased when pressure reached 100 MPa. HPH treatment decreased particle size, produced higher zeta potential and hence, improved water solubility, which resulted in higher emulsifying and foaming properties. Hazelnut meal protein suspensions displayed shear thinning behavior and higher G′ than Gʹ' which means suspensions had soft-gel network. For better understanding of internal structure, elastic and viscous behavior, creep and recovery tests were explained by Burgers and exponential decay models. Final percentage recovery increased after 100 MPa due to strengthened solid-like structure of protein suspensions. As a result, functional and rheological properties of proteins can be successfully improved by HPH treatment, and thus hazelnut oil industry by-products have added value once processed by HPH.