Concentrated whey protein ingredients: A Fourier transformed infrared spectroscopy investigation of thermally induced denaturation

Abstract

Thermal denaturation of whey protein solutions was investigated from a structural perspective utilising attenuated total reflectance – Fourier transformed infrared spectroscopy ( ATR ‐ FTIR ). Solutions (100 g protein/L, pH 7) of commercial whey protein isolate ( WPI ) powders and enriched protein fractions of β‐lactoglobulin (β‐lg) and α‐lactalbumin (α‐la) were heat‐treated at temperatures of 50–90 °C. Subsequent analysis by ATR ‐ FTIR highlighted the structural changes occurring as a direct result of heat treatments. Molecularly, WPI dispersions exhibited pronounced differences in denaturation behaviour depending on their method of manufacture. ATR ‐ FTIR is an informative tool to discern the structural molecular interactions not apparent through physical analysis of concentrated ingredients.