Effects Of Partial Gelatinization And Enzymatic Debranching On The Physicochemical Properties Of Starch

Starch is an important basic raw material in the food industry.During industrial production and processing,starch is often in a partially gelatinized state and directly affects starch processing characteristics.Therefore,in-depth research on the change law of physicochemical characteristics of starch with different gelatinization degrees is to further improve the starch starch foods.Provide theoretical basis for stability and industrial production applications.Using corn starch,potato starch,and mung bean starch as raw material,the degree of gelatinization starch was prepared under different heat treatment conditions.the thermal,retrogradation,and enzymatic hydrolysis properties of starch with different degree of gelatinization starch were studied in this thesis.The results of X-ray showed that,the crystal structures of different gelatinization degrees corn starch,potato starch,and mung bean navtive starch showed A-,B-,and C-type crystal structures.the greater the gelatinization degrees,the crystallinity of different gelatinization degrees starch was gradually decreased and eventually lost.the characteristic peaks of crystal structures starch was disappear and amorphous state;The results of pasting properties indicated that paste transparency and iodine blue value of partially gelatinized starch were higher than those of native starch,The dehydration rate starch was improved with the increase of degree of gelatinization,however,the freeze-thaw stability of the starch declined and as the freeze-thaw cycle time increased,the freeze-thaw stability of the starch became higher.The greater swelling of starch that at lower temperature,The solubility starch was improved with the increase of degree of gelatinization,The results of thermal showed that,The partially gelatinized starch had higher To,Tp,Tc;as the degree of gelatinization increased gradually,the gelatinization enthalpy of the starch declined.The results of SEM showed that,the surface of starch granule was became rough with the increase of degree of gelatinization,the greater the degree of gelatinization,the more obvious this phenomenon;with the gelatinization temperature increased some partially melting and agglomerateing;The results of polarized cross microscopy indicated that varying degrees of weakening and disappearing with the increased of degree of gelatinization.Compared with microscope,the particle granule of degree of gelatinization starch was melting and Swelling,particles have been melt and even broken.The pullulanase treatment was used to prepare gelatinized and debranched starch with different degrees of enzymatic hydrolysis.The results showed that the total sugar and reducing sugar content were gradually increased with the increased of starch gelatinization degree.Xray analysis showed that,the crystalline area of the sample was increased.The transparency and iodine blue value were improved after part of the pasted starch treating with prupantinosine de-support.The water analysis was improved and the freeze-thaw stability wsa decreased after the de-supporting treatment of the high paste starch.The DSC analysis showed that,after pullulanase debranching,the To,Tp,and Tc were increased.And the greater the paste,the higher the To,Tp and Tc values of starch particles.While the ?H had no significant change.The starch retrogradation results are as follows: partially gelatinized starches retrogradation degree increased accordingly as storage time increases,during the storage at 4 °C.the onset temperature(To),peak temperature(Tp),and conclusion temperature(Tc)were higher than that of native starch and the retrogradation enthalpy gradually decreased.The fully gelatinized starch retrogradation degree higher than that partially gelatinized starch 2-3 times and fully gelatinized starch had the greatest retrogradation enthalpy.The results of retrogradation kinetics indicated that,According to the Avrami equation that the retrogradation degree closely related to the storage time.The fully gelatinized starch retrogradation rate reaches Maximum and the more obvious retrogradation rate of different types of starches.The results of slowly digested starch content indicated that the slowly digested starch content decreasing gradually with the increased of gelatinization degree,and the least slowly digested starch content of the fully gelatinized starches.Partially gelatinized starch after pullulanase debranching treatment,with the increased of the degree of gelatinization,the content of slowly digested starch gradually decreased after debranching.