Study On The Freezing Parameters And Quality Improvement Of Frozen Steamed Bread Dough

This study investigated the making processes,quality improvement and shelf life prediction of the frozen steamed bread dough.The content including: determining the frozen dough making processes,optimizing the freezing parameters(freezing time and temperature) according to the response surface analysis and testing the dough freezing curve.Then,in order to improve the quality of frozen dough,the food additives,such as the emulsifiers,food gum,oxidizer etc was employed.And the impact of food additives on the freeze-thaw stability of frozen dough was studied.Finally,the acidity change of the frozen dough was performed during freezing storage at different temperature and a first-order dynamic model simulating the acidity changes of frozen dough was obtained.Through the research on the making processes and parameters of frozen steamed bread dough,the result showed that the optimal freezing parameters were: the freezing temperature-30℃and the freezing time 30 min.According to the response surface analysis,freezing time and freezing temperature had a significant interaction.Three kinds of food additives(SSL, xanthan Gum and vitamin C)were selected according to the single factor experiment.The results of the single factor experiments and the orthogonal experiments showed that the appropriate amount of the multiple additives in producing frozen dough steamed bread were: SSL 0.10%,xanthan Gum 0.01% and vitamin C 0.30%.Finally,the frozen bread dough was made with different recipes,whether the results of sensory evaluation,specific volume result,texture result,cracking rate is consistent with the results of the performance of orthogonal test.Dough freezing temperature curve results show that under the conditions of-30, frozen dough average rate of about 1.16 ℃ / min.Preliminary studied the impact of SSL,xanthan Gum and vitamin C on the freeze-thaw stability of frozen dough. The results showed that SSL and Xanthan gum can enhance the freeze-thaw stability of starch paste and flour paste.Vc can enhance the freeze-thaw stability of flour paste.But it’s influence to freeze-thaw stability of starch paste was not significant.Additive complex freeze-thaw stability test results show that: SSL,Vc and xanthan gum to improve the freeze-thaw stability of wheat flour has a synergistic effect.Monitor the changes of acidity during freezing storage under the temperature of-10℃,-15℃,-20℃ and build first-order dynamic model to simulate acidity changes of frozen dough to predict the shelf life of frozen steamed bread dough.The results showed that acidity gradually decrease with the storage time,moreover,the higher the temperature is,the faster the decreasing is.The predictive model of acidity is K=2.2314×104×e-27690/RT.The relative error of dynamics model of prediction value and actual measurement value is under 10%,it shows that this model can better predict the acidity changes during storage.