Measurement of Heat and Pressure Induced Denaturation of Whey Protein Isolate Using Reversed-Phase HPLC and FTIR-Spectroscopy

Abstract

The protein molecules experience various external stresses leading to denaturation of protein during the process of transforming original whey to the concentrated whey proteins or while the concentrated proteins are used in the protein-enriched food formulation. This study was designed for a comparative assessment of the denaturation of whey protein isolate (WPI) under an important thermal stress, isothermal heat treatment (IHT), and high hydrostatic pressure treatment (HPT). The type and extent of denaturation were determined using reversed-phase HPLC and FTIR spectroscopy. The HPLC results demonstrated that the isothermal heat treatment caused higher denaturation of protein due to IHT at 80oC for 600s (88.38%) than that of HPT (58.5%). However, the infra-red spectroscopic analyses suggested that the HPT caused severe destruction of the structural conformation of WPI. The state of protein has a great impact on food formation; hence, the findings of this study would alert the concentrate protein producers and protein-enriched food manufacturers to prepare more active functional foods. HIGHLIGHTS \xa0Heat (IHT) and pressure (HPT) stresses caused 88% and 58% WPI to denature, respectively. \xa0Reversed phase-HPLC determined the denatured protein through aggregation. FTIR together with HPLC is required for better characterization of denatured protein.