BEST MIXING PRACTICES TO MINIMIZE THE PARTICLE SIZE IN RECONSTITUTED NONFAT DRY MILK

摘要

The objective was to determine processing parameters that would minimize the particle size of reconstituted nonfat dry milk (NDM). Four mixing parameters were evaluated: equipment (blender versus recirculation), shear rate (high versus low), mixing temperature (4 versus 22C) and holding temperatures (4 versus 22C). In a second experiment, lab-scale homogenization and pH adjustment were evaluated. NDM reconstituted in a blender at 22C had the smallest particle sizes (0.133 to 0.135 μm). Shear rate did not affect particle size. Homogenization induced multimodal particle size distributions within a single dispersion, and this effect was exacerbated if the reconstituted NDM was adjusted to pH 5, 6 or 7. Changes in casein micelle structure may explain the effect of homogenization on particle size.