Effects Of Trehalose On Properties Of Starch And Frozen Dough Steamed Bread

The project were selected potato,corn,wheat starch,wheat flour frozen dough and frozen dough steamed bread as the main research objects.To study the effects of trehalose on the physicochemical and processing properties of starch,frozen dough and frozen dough steamed bread.The effects of trehalose on starch paste properties,gelatinisation,granule morphological,thermal enthalpy properties,and retrogradation degree were studied by using transflective polarizing microscope,thermogravimetric analyzer,and DSC(differential scanning calorimeter).The results showed that the addition of trehalose can reduce sedimentation,enzymatic hydrolysis rate and iodine blue value,and improve the transparency and freeze-thaw stability of starch paste.DSC analysis showed that the starch gelatinization temperature increased after adding trehalose,which helped to maintain its particle shape and reduce the aging rate;Thermogravimetric analysis shows that the stability of starch granules increased after trehalose added,the degradation temperature was higher,and the decomposition rate reduced.While sucrose has a similar effect,but the effect was worse than trehalose.Used The rheometer,TPA and other technics to make the study of the mechanism and influence of water,yeast cells,gluten network,starch and other components in the frozen dough system became possible,compared to sucrose.Under the same freezing time,added sugar can reduce the water loss rate of the frozen dough system;increase the survival rate and gas production capacity of yeast cells;increase the specific volume and elasticity of the dough,and reduce the hardness;Through the analysis of rheological properties,it was found that sugars can also increase the elastic modulus and viscosity modulus of the dough system,reduce the loss coefficient,and increase the viscosity of the dough system.The results showed that the antifreeze protection effect of trehalose was much greater than that of sucrose,and the trehalose was most suitable content is 5%.By investigating the changes of acidity of frozen dough with different trehalose contents(0%,3%,5%),and constructed a dynamic model between the acidity and the added amount,to predict the quality change and shelf life of frozen dough.The results showed that with the extension of the freezing time,the change in the acidity of the frozen dough gradually increased.As the amount of trehalose added increased,the acidity decreased.The change in acidity and time was in line with the first-order chemical reaction kinetic model,whose(0%、3%、5%)equation was: dc/dt =-0.0845 c,dc/dt =-0.0579 c,dc/dt =-0.05656 c.The greater the amount added,the smaller the reaction rate.The correlation coefficients were all greater than 0.9,the fitting degree was high,and the relative error between the actual acidity and the predicted value was less than 20%.Therefore,the first-order reaction kinetic model can be used to predict the shelf life of trehalose frozen dough.The effects of trehalose on the cooking characteristics and product quality of frozen dough steamed bread were analysed by analysis techniques such as texture analyzer and high-quality portable computer color difference meter.After adding trehalose,the appearance was fuller,and the color was whiter,the skin was smoother,the texture was softer,the hardness was reduced,and the elasticity was increased,which had good sensory and texture qualities.