E) were significantly affected by WR, T, and FFR. The higher WR and lower FFR resulted in a decrease in moisture content and ?em class="a-plus-plus">E. WR and FFR had extremely significant effects on VC content and hygroscopicity (P-lt;-.01); with lower WR and FFR, higher values of VC content and hygroscopicity would be received. The effect of WR was the most significant variable among others. The optimum conditions that maximizing VC content and minimizing contents of moisture, ?em class="a-plus-plus">E, and hygroscopicity of jujube powder were found as WR of 3, inlet air temperature of 140?°C, and FFR of 3 ( i.e., 11?ml/min). Under these conditions, the response values were moisture content of 3.36?%, lightness of 83.32, ?em class="a-plus-plus">E of 9.92, VC content of 205.10?mg/100?g, and hygroscopicity of 18.59?%, respectively." />