Study On Critical Processing Technique Of The Frozen Dough Of Potato Bread

In this study, by-product from potato products processing was used as the raw material of potato powder, which is used to development of the frozen dough of potato bread. First, the appropriate proportion of potato powder added in bread was evaluated and determined. Based on the first phase study, the main factors that influence processing of the frozen dough of potato bread were discussed and the critical processing technique parameters were optimized. Then, with the discussion of baking and texture characteristics of the frozen dough of potato bread, the most suitable additives and the best additive quantity were confirmed. Meanwhile, the microstructure of the frozen dough of potato bread during frozen storage was also studied in this research. The main results were as follows:(1) Study on the effect of potato powder proportion on the baking, texture characteristics and sensory qualities of breadA potato bread was made of flour and potato powder which used the by-product from potato products processing as the raw material. The appropriate proportion of potato powder was investigated by detecting the effect of potato powder on the baking, texture characteristics and sensory qualities of bread. The results showed that a proper proportion of potato powder could improve the bread qualities, such as nutrition strengthening, flavor and volume increasing, making bread soft and elasticity, improving the yield of bread. However, excessive potato powder also decreasing the quality of the bread. Considering the effect of potato powder on the baking, texture characteristics and sensory qualities of bread, the results showed when the bread was made with15%potato powder the ideal quality could be obtained.(2) Optimization of critical technical parameter of the frozen dough of potato breadBy single-factor experiments, the effects of critical production technology (the dose of yeast, water addition, dough making time and pre-fermentation time on frozen potato bread dough) were discussed. Meanwhile, basing on the quadratic general rotary combination of experiment, the relative ferment ability of the frozen dough of potato bread, hardness, specific volume, height to diameter ratio and sensory evaluation of finished bread were taken as indicators. The regression equation about the bread specific volume Fand the dose of yeast X2, water addition X2,dough making time X3, pre-fermention time X4was established as follows: Y=3.82286+0.02958X1+0.02625X2+0.03292X3+0.03125X4-0.2061X12-0.04436X22-0.02686X32+0.05063X,X2-0.03688X,X3The results showed that the optimized critical technical parameters of the prepared frozen dough of potato bread were as follows:the dose of yeast was2.7%, dough making time was17.5min, water addition was63.5%, pre-fermention time was24.5min. Based on these conditions, the specific volume of the potato bread was3.87mL-g-’and there were no significant differences between the theoretical value and the actual measured value(P>0.05).(3)Research on the quality improver of the frozen dough of potato breadOn the basis of single-factor experiments, the suitable additives were screened out and the orthogonal experimental design was adopted to obtain the optimal proportion of quality improver. The results showed that the optimistic amount of additive for the frozen dough of potato bread was that:2.5%vital gluten,0.08%SSL-CSL,0.35%monoglyceride,0.20%carrageenan. Under this condition, the frozen dough of potato bread was made and stored for90days at-21℃, and then, the specific volume of potato bread was4.33mL·g-1. The studied revealed that the composite improver could effectively improve the quality of the frozen dough of potato bread.Scanning electron microscopy was employed to observe the microstructure of the frozen dough of potato bread during frozen storage. The electron microscope scans showed that the gluten protein network of the frozen dough of potato bread was damaged during frozen storage. However. compared with non-additive frozen dough, the added one was less damaged. The study demonstrated that the composite improver helped to mitigate the damage caused by freezing and improved the quality of he frozen dough of potato bread.