Studies On Process Of Laomian Frozen Steamed Bread Dough

In this work, in order to study the producing process of frozen dough steamed bread fermented by laomian, firstly, the producing process of frozen dough steamed bread fermented by laomian and the mixture of laomain and yeast were optimized by response surface method respectively, and compared the differences of two methods and the differences of the two methods were compared; next, the effects of the freezing rate and frozen storage time on fermentation and rheological property of frozen dough and quality of streamed bread were investigated; Several different wheat were choosed,the correlations of frozen dough quality and wheat grain quality,wheat flour quality and rheological characteristics were studied.In addition, for improving the quality of steamed bread further, the additive formulation was optimized. The results were as follows:The optimal producing process condition of frozen dough steamed bread fermented by laomian: the supplementation level of laomian 51 g, the amount of water added 40 ml, the time of fermentation 62 min; The optimal producing process condition of frozen dough steamed bread fermented by the mixture laomian and yeast: the ratio of laomian 0.6, the amount of water added 47 ml, the time of fermentation 35 min. Comparison of two frozen dough steamed bread found the surface of laomian frozen dough was easy to cracking, internal structure was relatively dense, sensory score of steamed bread was low; After adding some yeast, the phenomenon of cracking was improved, small pores were evenly scattered, Sensory score of steamed bread was increased.Effect of freezing rate, frozen storage time on the fermentation and rheological properties of frozen dough and quality of steamed bread were investigated. Elasticity modulus, viscous modulus, maximum height and the volume of gas release were declined with the extension of frozen storage time and the decrease of freezing rate. Frozen dough fermented by the mixture of laomian and yeast was slower than frozen dough fermented by yeast. As extension of frozen storage time, hardness of frozen dough steamed bread was largened and spring, chewiness and sensory score were diminished significantly. Frozen dough fermented by the mixture of laomian and yeast was better than frozen dough fermented by yeast. Freezing rate R2 and R3 have no obvious effect on hardness, spring and chewiness of steamed bread. Taking energy dissipation and profit into consideration, the optimal conditions for the Frozen dough steamed bread was freezing rate R2 and within fifteen days.Sensory score of frozen dough steamed bread had significantly positive correlation with wheat hardness index and wheat flour gluten index, cementitious property and spring had significantly negative correlation with wheat flour gluten index, the results showed that within certain range,the higher the wheat hardness and the wheat flour gluten index, the better the quality of frozen dough steamed bread. specific volume and resilience of frozen dough steamed bread had extremely significantly negative correlation with gelatinization point, Farinograph quality number had significantly positive correlation with specific volume and sensory score, stable time had significantly positive correlation with sensory score; the time of the dough began to leak had significantly positive correlation with specific volume and resilience. The results showed that the higher the gelatinization point, the longer the stable time, the larger the farinograph quality number, the later the time of the dough began to leak, the better the frozen dough steamed bread.The optimal additive formulation of frozen dough steamed bread fermented by the mixture of laomain and yeast: trehalose3.55%, glucose oxidase30.65mg/kg, locust bean gum 0.95%, h ydroxypropyl potato modified starch 1.39%. The results of the response surface analysis show that Additives improved frozen dough quality significantly. The primary and secondary order of various additives: hydroxypropyl potato modified starch>trehalose>locust bean gum>g lucose oxidase.