Effects of processing parameters of spray drying on some of the quality attributes of whey protein concentrate hydrolysates

The effect of outlet air temperature of spray drying and feed total solids (TS) on some of the quality attributes of enzymatically hydrolyzed whey protein concentrate was elicited. Cheddar cheese whey was ultrafiltered and diafiltered to 25 % TS. The retentate was hydrolyzed by neutrase enzyme to obtain 8.0 % protein hydrolysis followed by vacuum condensing to 30, 35, 40, and 45% TS and spray drying at various outlet air temperatures (70, 75, 80, 85 degrees C). As the temperature of drying increased, the moisture content of powder decreased significantly at all levels of TS. Lower outlet air temperatures (70 & 75 degrees C) could not bring down the moisture content below 5% at higher levels of TS in the feed (40 & 45%). Increasing TS in the feed from 30 to 45% increased bulk density of powder. Increasing the TS from 35 to 45% had an adverse effect by significantly decreasing whey protein nitrogen index, increasing insolubility index and Hydroxymethylfurfural contents. The whey protein hydrolysates dried at a combination of 35% TS and outlet air temperature of 75 degrees C resulted in superior quality product taking into account all the quality attributes.