Optimization of Whey Powder Production Yield Using Spray Dryer and Assessment of Physicochemical Characteristics of the Whey Powder

Background and Objectives: Whey powder is a product of water drying process separated from the curd during cheese making processes. Furthermore, whey is an organic waste of cheese production, including significant uses in food industries, particularly in dairy and fermentation stages because of its special characteristics and high quantities of lactose.  Materials & Methods: In the present study, two spray drying parameters including dry matter contents of whey (30, 40 and 50% T.S.) and dryer temperatures (150, 200 and 250 °C) were optimized using response surface methodology and then physicochemical characteristics of the powder were assessed as responses. Results: Results showed that by increasing dry matter contents of input feed solutions, whey powder density and production yield increased but changes in moisture contents were not significant (p > 0.05). As the whey concentration increased (up to 40% T.S.), the powder solubility was enhanced and then decreased. As the dryer inlet temperature increased, the production yield and solubility of the powder increased and the powder moisture content and bulk density decreased. The optimum conditions for whey powder production to achieve the highest production yield and solubility and the lowest moisture content and bulk density of the powder were reported as 39.37% dry matter content of whey and 250 °C dryer inlet temperature. Conclusion: Based on the characteristics of whey powder, it can be used as a raw material in various fermentation processes and cultures. Moreover, environmental pollutions by dairy plants decrease by production of whey powder.