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

Thermal denaturation of whey protein solutions was investigated from a structural perspective utilising attenuated total reflectance - Fourier transformed infrared spectroscopy (ATR-FTIR). Solutions (100g protein/L, pH 7) of commercial whey protein isolate (WPI) powders and enriched protein fractions of -lactoglobulin (-lg) and -lactalbumin (-la) were heat-treated at temperatures of 50-90 degrees 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.