Optimization of spray drying of colostrum protein ingredients–A rheological approach

Abstract Investigation was carried out to develop spray dried immunoglobulin-rich colostrum powder by employing suitable technological interventions based on rheological analysis. The microfiltration (MF) permeate of skim colostrum and colostrum whey were fractionated and concentrated by ultrafiltration to 2.03 and 2.38 fold to obtain skim colostrum retentate (SCR) and colostrum whey retentate (CWR), respectively. Their thermal gelation behaviour as affected by variations in pH, total solids and added thermal protectants were evaluated, using temperature sweep test and the data were utilized for the optimization of spray drying conditions. TGT for SCR and CWR was 72.2 °C and 74.5 °C. Based on TGT, the outlet air temperature was maintained in the range of 68–72 °C. Under optimized conditions of spray drying 88.5% of total Igs of feed were retained with excellent and acceptable insolubility indexes in powders. Other powder properties were comparable to freeze dried powder. Rheological analysis of protein-rich preparations could be adopted for optimizing the spray drying conditions without adversely affecting protein bioactivity and reconstitution properties.