Physicochemical and functional properties of safflower protein isolate: Effect of drying methods and spray drying temperatures

In this study, the effects of the drying method and spray drying inlet air temperature on the color, surface morphology, hydrophobicity, powder and functional properties of safflower protein isolate were investigated. Safflower protein was extracted using the alkaline extraction and isoelectric precipitation method and then dried using freeze-drying and spray-drying at 140, 150, 160, 170, and 180 degrees C inlet air temperatures. When compared to the spray-dried samples, freeze-dried safflower protein isolate had lower cohesiveness (1.18) and better flowability (15.12%) with higher bulk density (0.31 g/cm3) and lower tapped bulk density (0.37 g/cm3). Additionally, its wetting time (9.00 s) was also found to be lower. On the other hand, spray-dried samples exhibited lighter color, higher foaming capacity (30.00-38.75%) and stability (87.50-89.17%), and emulsion activity (51.25-54.50%) and stability (85.76-87.51%) than the freeze-dried sample. Moreover, it was found that the foaming capacity and emulsion activity of safflower protein spray-dried at 140 degrees C were higher than those of other spray-dried samples. Overall, freeze-dried safflower protein showed better powder properties, while spray-dried samples had better functional properties. Consequently, it was shown that the choice of drying method and spray drying inlet air temperature were critical for the powder and functional properties of safflower protein.