Mixing effects and noodle quality of differential horizontal mixers with double shafts

Abstract: Horizontal mixers with double shafts are commonly used in the noodle industry. They can be divided into constant speed and adjustable speed according to the mixing speed, and rod-shaped blades and blade-shaped blades with certain angles on the basis of mixing blades configuration. Two kinds of horizontal mixers with double shafts and three kinds of wheat flours were selected to analyze the mixing effects and noodle quality, aiming to understand the mixing effects of horizontal mixers with double shafts with different mixing speed and blade configuration. The two mixers were a model 550 mixer with rod-shaped blades and constant mixing speed (80r/min) and a model 765 mixer with angular blade-shaped blades and adjustable mixing speed (low-speed-70r/min and high-speed-105r/min). The total time of each mixing experiment was 13 minutes and the moisture of the dough crumbs were 32%～33%. Mixing was carried out in duplicate. The moisture uniformity and particle size distribution of dough crumbs, color uniformity of sheets, tension properties (maximum tensile resistance and extensibility) of fresh noodles, cooking properties (dry matter loss and water uptaken during cooking) of dried noodles and texture profiles of cooked noodles were measured, and the effects of mixing modes on these quality indicators were analyzed. Results showed that three mixing modes had significant effects on the qualities of dough crumbs, dough sheet, and noodles. The model 765 mixer had better mixing effects compared to the model 550 mixer, with a better moisture uniformity of dough crumbs, medium dough crumbs particles size, lower percentage in large particles (particle diameter ≥4000 μm), and better uniformity of dough sheet color. Fresh noodles made of the dough from a model 765 mixer also had higher maximum tensile resistance and extensibility, and cooked noodles were firmer and had higher gumminess and chewiness. The model 765 mixer with different combinations among the high speed and low speed mixing times had different mixing effects and noodles quality. When it was under the condition of parametersⅠ, namely low-speed 300s and high-speed 480s, it could produce relatively smaller dough crumb particles, and thicker and whiter sheet. However, the resilience of cooked noodles were lower than those produced by the mixer under parameters -low-speed 500 s and high-speed 280 s. Different wheat flours required different mixing modes. The model 765 mixer with parameters was more suitable for Gaojin flour with a larger particle size and higher gluten quality, having higher maximum tensile resistance of fresh noodles, higher hardness, gumminess, chewiness and resilience of TPA parameters of cooked noodles. For Shangbai flour with relatively smaller particle size and weaker gluten quality, parameters with lower intensity mixing were more suitable.