Study On Non-alum Corn Starch Vermicelli And Physicochemical Properties Of Starch

By using corn starch as main raw material of the experiment,we studied on the preparation process of non-alum corn starch vermicelli.Including processing,quality and physicochemical properties of the research.The effects of additives on the quality and structure of corn vermicelli were analyzed,and the performance of each additive was evaluated by single factor and orthogonal experiment.The effects of different processing conditions and optimization methods on the preparation of vermicelli were discussed.In order to search for suitable corn starch,we explored the physical and chemical properties of corn starch and the change regulation of mechanism.It was provided that the industrial production of corn production and a theoretical basis for the non-alum vermicelli.The main contents and conclusions were as follows:1 To study on the effect of compound additives on the quality non-alum corn vermicelli,it was studied that the effect of konjaku flour,guar gum,composite phosphate and calcium chloride on breaking rate,paste soup absorbance and degree of swelling of corn starch vermicelli.The results showed that the paste soup absorbance was valued as an index for additive factors that the impacting orders was D﹥B﹥C﹥A.The amount of non-alum additive was konjaku flour 0.2%,guar gum 0.3%,composite phosphate 0.4% and calcium chloride 0.3%.Under the optimized conditions,the corn starch vermicelli breaking rate was 8.7%,the paste soup absorbance was 0.159 and the degree of swelling was 314.5%.It indicated that additives could replace alum to improve the quality of vermicelli.2 Optimization of processing technology of corn vermicelli by Response Surface Methodology.By the way of study the processing technology of non-alum corn starch vermicelli,and compare the quality.The breaking rate,paste soup absorbance and degree of swelling were used as index for single factor experiment.Investigated the processing effect of paste content,moisture content,boiling time and frozen temperature on the corn starch vermicelli.According to the Response surface methodology and TPA evaluation,the optimum process was determined.The regression model was established with the breaking rate as response value.The results showed that the optimum process was paste content 4%,moisture content 50%,boiling time 10 min and frozen temperature-10℃.The significance sort of response value was X1 > X3 > X2 > X4,meanwhile the minimal breaking rate was 8.25%.The results of response surface was reliable,the texture of corn vermicelli with optimum condition was productive.3 To study on physicochemical properties of corn starch.The gelatinization temperature of Zhanyi corn starch was lowest at 53.608℃ by DSC gelatinization.According to the determination of fat protein and aging results,the physical and chemical properties of Zhanyi corn starch were better than the other two kinds of starch.In the DSC long-term retrogradation could be seen that second peak enthalpy of Zhanyi starch value reached 795.76 J/g,then in the determination of thixotropic properties,the dough thixotropic loop area was also the largest.By using a combination of optimized starch and additives to the determination of the RVA viscosity curve,the combination of corn starch and GG had better viscosity,it can be seen that guar gum as the best gel properties.Then research on the quality evaluation system to determine the quality of the index range of high grade vermicelli.Such as hardness>250,0.70<cohesiveness<0.85,the vermicelli was the best.This quality evaluation index can determine a series of excellent vermicelli properties.When in the determination of TPA texture,Zhanyi non-alum corn starch vermicelli hardness was 423.05 g,its tensile strength reached 1158.26 g.It also showed that it was not easy to break,and appeared the good characteristics of cooking.From the different angle of starch and more indexes were prepared better conditions to produce the vermicelli.4 To research on the preservation and digestibility of corn vermicelli,according to the drying curve,it was found that the cooking loss,solid loss and soluble loss were less when temperature at 45℃.The suitable drying temperature was about 45℃.During the experiment of ash content,the ash content of the corn vermicelli has reached 0.52g/100 g at 28 days,and the superiority of additive in the vermicelli was obtained.The microbiology test results showed that 0.3% of potassium sorbate could restrain bacteria to grow and prolong the storage period.Observation of non-alum vermicelli were analyzed by scanning electron microscope in the storage conditions of 4℃,0℃,-6℃ and-14℃.It could be concluded that the storage temperature at-6℃ was the most suitable storage condition,which were determined by combining the internal structure and the characterization structure.In addition,it was found that the content of SDS was about 45.5g/100 g,and the content of resistant starch was about 14g/100 g.In the long term,the proportion of resistant starch RS did not change,so it could be seen that the storage time has a certain degree of influence on starch properties.