Physical and storage properties of high milk protein powder

High milk protein powder (HMPP) was prepared by ultrafiltration and diafiltration of skim milk to 21% protein and spray drying. The HMPP had lower loose and packed densities than non-fat dry milk (NDM) but the true densities of both powders were similar. The solubility index (SI) rose in HMPP when stored above 10 degrees C but remained unchanged in NDM, regardless of storage temperatures. No hydroxymethylfurfural (HMF) was detected in HMPP stored at -20 to 45 degrees C for up to 3 1/2 months, however, HMF increased in NDM. The absence of HMF in HMPP may be in part attributed to its low lactose content.