The Effect Of Hydrocolloids On Gelatinization And Retrogradation Of Castanea Henryi Starch

Castanea henryi is one of the important food woody plants, the processing characteristics and features of castanea henryi kernels are closely related to their starch quality. Castanea henryi starch have poor shear resistance, low gel strength, poor thermal stability and easy to regenerative, which seriously affected the processing applications of castanea henryi. Adding hydrophilics to starch, can significantly increase its acid, heat and shear resistance, improve changing product texture caused by starch retrogradation. In this paper, combining various modern instruments analyze the interactions between castanea henryi starch and hydrophilics, in order to improve the quality of castanea henryi products, improve its product processing and guide its new product development.Firstly, this paper analyze and compare the effects of three different hydrophilics on gelatinized and rheological properties of castanea henryi starch. The RVA results show that, compared with separate system of castanea henryi starch, the peak viscosity and final viscosity increase after adding guar gum, carrageenan and xanhan gum. The xanthan gum and carrageenan were added, the hot and cold stabilization of mixed system increase, but guar gum have no significant variation to it. The guar gum and carrageenan increase the setback of mixed system, but xanthan gum reduce it; The DSC results show that, initial gelatinization temperature To and peak gelatinization temperature Tp increase, gelatinization enthalpy AH reduce of mixed system after adding three different hydrophilics; The rheoloy results show that, the storage modulus G’and loss modulus G" of mixed system significantly increase, its gel strength become large, fluid index n become smaller, the mixed system pseudoplastic enhance. The xanthan gum and guar gum reduce G’and G " dependence of mixture system on frequency but carrageenan unchange it. The MMR results show that, the transverse relaxation time T2 reduce that its mobility reduce of mixed system; The SEM results show that, the quantity of empty increase, the gap reduce of mixture system, and the structure formation is more compact.Secondly, combining dynamic rheometer, texture analyzer, DSC, X-diffraction, low-field NMR, FTIR and SEM study the influence three different hydrophilics on the retrogradation properties of castanea henryi starch. The results showed that compared with separate system of castanea henryi starch, the G’growth rate slows down, the hardness decreases of mixed system after adding hydrophilics, this reflects hydrophilics inhibit the retrogradation of castanea henryi starch; Meanwhile the retrogradation degree and relative crystallinity of the mixed system reduced, indicating that hydrophilics inhibit amylopectin crystallization increasing speed, delay its retrogradation; The transverse relaxation time T2 which show the flow moisture content of mixed system increases,the proportion reduce which amorphous zone convert to crystalline regions, so prevent the retrogradation of amylopectin. Fourier infrared spectrum show that compared with separate system of castanea henryi starch, hydrogen bonding of mixed system enhance, gel strength increase after adding hydrophilics; The electron microscope show that the network structure of mixed system become more dense and compact.