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

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 calorimetry
• Moisture content
• Morphology
• Protein 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.