The Use of Surface Active Compounds as Additives in Spray Drying

Yields of spray drying pure lactose (10% w/w) solutions, as well as lactose-protein mixtures with casein and whey protein isolate (WPI) concentrations between 0.5 and 50% w/w of the total solids, were measured. Proteins were found to improve spray-drying yields more significantly at higher inlet air temperatures. Scanning electron micrograph (SEM) images showed that adding proteins to lactose solutions caused surface morphology changes on the products. X-ray photoelectron spectroscopy (XPS) analysis showed that the surface concentrations of proteins were higher than their bulk concentrations. Modulated differential scanning calorimetry (MDSC) measurements showed that the mixtures undergo glass transitions at similar temperatures to pure lactose.