Abstract: Mixing is the key step in dried noodle processing, thus the sufficient mixing process capability is very important for guaranteeing the stable dried noodle quality. In order to improve the quality control of mixing, quality traits of dough crumbs were monitored and measured. Control chart methods were used to determine whether the process was in a state of control or not. The factors affecting quality variance were investigated, the corresponding control methods and technical parameters were proposed, and the improvement effect was estimated. The results showed that the dough crumb moisture and dough crumb moisture uniformity fell outside the control limits when the product line was monitored for 20 days. The factors affecting quality variance mainly included excessive noodle crumbs, insufficient mixing time and inappropriate quantity of water added as well as high watering speed. The major methods to improve the process capability included choosing stable quality wheat flour suitable for noodle processing, choosing appropriate way and mixing time, limiting the weight of dried and wet noodle crumbs and making personnel standardization. When SPC was applied in quality control of mixing, the variances of dough crumb moisture and dough crumb moisture uniformity were reduced significantly, and the process capability levels were improved.

Key words: dried noodle processing, mixing, statistical process control, control chart, quality variance, process capability