Development And Quality Characteristics Analysis Of Purple Sweet Potato Granules Steamed Breads And Wet Noodles

This paper mainly studies the effect of higher addition of purple sweet potato granules(PSPG)on dough properties,the quality of steamed breads and noodles.The main research contents and results are as follows:The effect of different proportions(0%,10%,20%,30%,40% and 50%)of PSPG on dough rheological properties was explored.The results of dough tensile propeties showed that,the addition of PSPG would made the dough tensile properties worse,the gluten strength of the dough became weaker and the steaming performance of the dough was reduced.The results of silty propertyof the dough showed that the forming time,stable time and silty index of the dough gradually decreased,the softening degree and water absoption rate gradually increased,and the dough became softer and more easily deformed with the increase of the addition of PSPG.It is not conducive to the forming of steamed bread and other foods.The results of dough gelatinization properties showed that the peak viscosity,minimum viscosity,attenuation value,final viscosity,retrogradation value and peak time of the dough decreased significantly with the increase of PSPG addition,and the processing charcteristics of the dough decreased.However,the addition of PSPG addition extened the shelf life of the product and made it easier to store.After adding PSPG,the dough properties have improved.Based on the rheological properties of the dough,the results showed that,in order to made the steamed food have good quality,the maximum amount of PSPG added is 40%.The processing technology of PSPG steamed breads was determined by single factor and orthogonal experiment.The results showed that the best formula of PSPG steamed breads was40% PSPG,15% gluten flour,16% glutinous rice flour,millet flour 20%;the best fermentation parameters are 1.0% yeast addition,fermentation time 70 min,fermentation temperature 32?,and proofing time 16 min.The color of PSPG steamed breads becomes darker and the porosity becomes larger with the increase of the amount of PSPG.The results of in vitro digestion test showed that the starch content and resistant starch content of PSPG steamed bread were higher than wheat flour steamed bread,which were 60.74% and 70.09%,respectively.However,the hydrolysis rate and predicted blood glucose index of PSPG were lower than wheat flour steamed bread.The antioxidant test found that the total phenol content,DPPH and ABTS of PSPG steamed bread was higher than that of wheat flour steamed bread.In the process of refrigeration,the pH of PSPG steamed bread drops slowly,the water content is reduced,the water migration is slow,the hardness and chewiness increase,the enthalpy value rises,and the recovery speed is slow.PSPG steamed breads is a healthy food with rich nutrition,strong antioxidant,slow aging rate and long shelf life.The PSPG was applied to making wet noodles,the effects of different PSPG addition on the breaking rate,cooking loss rate,elongation rate,water absorption rate,and expansion rate of wet noodles were explored.As the amount of PSPG added increase,the quality of noodles deteriorates.It is concluded that 45% of the PSPG is the maximum addition.The results of single factor and orthogonal experiments test showed that the best formula of PSPG wet noodles is 45% PSPG,5% gluten,55% water,and 3% salt.The PSPG wet noodles made with this formula have bright color,moderate elasticity,and good taste.With the addition of 0.21%L-ascorbic acid,the color fading of the PSPG wet noodles was alleviated during the cooking process,the noodles are bright in color and the pH is moderate.The total phenol content of the PSPG noodles with the best formula is 138.03mg/g,and the free radical scavenging rates of DPPH and ABTS were higher than those of wheat flour steamed bread,95.77% and74.27%,respectively,and the antioxidant capacity was stronger.