Spray drying of ACE-inhibitory enzyme-modified white cheese

An angiotensin-I converting enzyme (ACE)-inhibitory enzyme-modified cheese (EMC) was spray-dried at different inlet drying air temperatures, feeding pump rates and spraying air flow rates. Powder moisture content, bulk density, porosity, production yield and particles size were responses of interest measured. Response surface optimisation determined that if the cheese paste is pumped at feeding pump rate of 5%, sprayed with the compressed air at rate of 400Lh(-1) and dried by an air at temperature of 154 degrees C, minimum moisture content is achieved for the produced powder. Spray drying decreased the ACE-inhibitory of EMC significantly, but the powder was still extremely bioactive. Scanning electron microscopy (SEM) images revealed that inlet drying air temperature of 150 degrees C yielded a powder with relatively well-separated particles. Higher drying air temperatures resulted in lower browning indices for the EMC powder.