Effects of Process Variables on the Denaturation of Whey Proteins during Spray Drying

Abstract

Abstract The effects of varying feed concentration (20–40% w/v) and outlet temperature (60 to 120°C) on whey protein denaturation (determined by DSC) and solubility (at pH 4.6) have been investigated in a pilot-scale co-current spray dryer. The study confirms that low outlet gas temperatures (60 and 80°C) produce the lowest amount of denaturation and solubility loss, with almost complete denaturation observed at 120°C along with a less dramatic reduction in solubility. Slightly more denaturation and loss of solubility was found with a 40% feed concentration. It is hypothesized that crust formation, resulting in high particle temperatures while still maintaining a wet core, is likely to lead to high levels of denaturation. Keywords: Differential scanning calorimetryMoisture contentMorphologyProtein solubility ACKNOWLEDGEMENT We gratefully acknowledge the Commonwealth Scholarship Commission, UK, for the award of Commonwealth Scholarship to CA, which enabled this work to be carried out. Notes ∗Trial 2 and ∗∗Trial 3: same conditions of first trial, but with different batch of feed material.