The effect of feed flow rate was only investigated for whole milk powder. Table 2 shows the effect of feed flow rate on the spray drying parameters and powder moisture content. As feed flow rate increased, more milk was atomized into the drying chamber and produced larger liquid droplets. Larger droplets had small surface area may reduced the outlet air temperature and hence, outlet air humidity and relative humidity became higher. Larger droplets increased the distance to travel the heat to the centre of the droplets and also increased the distance to travel the moisture from the centre of the droplets the surface. Hence, the moisture is difficult to evaporate and caused the powder cannot dry enough. Studies conducted by other researchers also confirmed these findings [9-11, 14-15].