Study On Production Of Frozen Dough Steamed Bread And Its Quality Improvement

The standardization and convenience of frozen dough technology promoted the development of the industrialization and brand management mode of quick-frozen food industry.But the frozen dough technology had the disadvantages of dough quality deterioration,such as the small volume of the frozen dough steamed bread and the prolongation of the time.Particularly,decreasing of yeast activity and structrual destruction of the gluten are the main factors affecting the quality of the frozen dough.To improve the quality of frozen dough,we used the Plackett-Burman Experiment and the Steepest Ascent Design to screen out the key factors in the production process of frozen dough steamed bread.Afterwards,we evaluated the optimized design process by the Box-Behnken surface method.Until now,there are not too many studies on the quality improvement of frozen dough steamed bread.Thus,it became a hot spot for the development of the quality improved additives.This study combined two traditional and two optimized addittives to inversitgate their effects on the quality of frozen dough steamed bread.We analyzed the growth activity of yeast,the texture profile analysis of steamed bread,the secondary structure of the gluten protein and the electron microscope structure of the dough.And then,the collected results were systemactically compared and analyzed to evaluate the quality improvement for our optimized improvers.The main results were as follows:1.By the Plackett-Burman and the Steepest Ascent Design,we selected key factors and levels in the production process of frozen dough steamed bread.These factors and levels included 0.8% yeast addition,38? fermentation temperature and 30 min fermentation time.And then,we determined the optimum process by Box-Behnken response surface optimization.0.8% yeast addition,37.5? fermentation temperature,29.60 min fermentation time,and the optimal frozen dough steamed bread was obtained at this time.The values were2.42±0.10 mL/g,1.52±0.13 g and 2074.67±72.71 gf for specific volume,fermentation force and hardness of the frozen dough respectively.This suggested our optimized processing parameters can improve the quality of frozen dough steamed bread.2.Based on the optimized parameters,we selected two traditional modifiers(xanthan gum and protease)and two new additives(ice structuring proteins and stachyose)to optimize the quality of frozen dough steamed bread by Box-Behnken response surface optimization.The results showed signifcant effects of the ice structuring proteins and stachyose on the quality of frozen dough steamed bread(p<0.05).However,the effects ofprotease and xanthan gum were not significant(p>0.05).The optimized formula was 0.01%ice structuring proteins,0.04% xanthan gum,0.01% protease,and 2.68% stachyose.The values were 2.71±0.15 mL/g,1.74±0.08 g and 1626±18.83 gf for specific volume,fermentation force and hardness of the frozen dough respectively.The specific volume and fermentation capacity of the unmodified steamed bread were 12%,14.5% and 21.6%,respectively,suggesting the compound additive can effectively improve the quality of the frozen dough steamed bread.3.Following the past of the cold storage time,the yeast activity decreased in the frozen dough.The hardness,chewiness and Gumminess of steamed breads increased.The amounts of the a-helices of the gluten protein decrased,the network structure of gluten gradually decreased,the starch granules were separated from the gluten structure,and some starch granules were completely exposed to the outside.According to the above indexes,we analyzed the quality changes of the frozen dough steamed bread and found the quality of the modified frozen dough steamed bread was greatly improved.This result verified the effectiveness of the compound improver on the quality improvement of the frozen dough steamed bread.The purpose of this study aims to improve the quality of frozen dough steamed bread.In addition,our study can promote the industrial production and deep processing level of frozen dough steamed bread.This study will provide theoretical reference and technical support for promoting the industrialization of the frozen dough technology of Chinese pasta.