Study On Gel Property Of Multi Grain(Bean) Starches

Physicochemical properties of eight kinds of starch including broad bean, pea, mung bean, buckwheat, barley, millet, proso millet and waxy proso millet starch were investigated in this paper, alterations of physicochemical property during retrogradation and factors influencing gel properties of starch were analyzed. These researches provide references for the improvement of gelled foodstuff based on starch. The main conclusions are as follows:1. The surfaces of legume starch granule were smooth with the granule displayed oval or round shape, X-shape was clear under polarized light; The smooth barley starch granules exhibited a disk with tabular shape and showed obvious cross shape or X-shape; Other cereal starch granules had angular shape, the cross located at the center of granule. Legume starches exhibited C type of X-ray pattern, while cereal starches had A-type X-ray pattern.Onset temperature and peak temperature and conclusion temperature and enthalpy of gelatinization for legume starches were all lower than cereal starches, indicating that the structure of cereal starches was more organized and compact. The freeze-thaw stability for legume starches was worse than cereal starches. All starch pastes were pseudoplastic fluid, thixotropy for buckwheat starch was minimum, while waxy proso millet starch was opposite.2. Phenomena that the intensity of diffraction peak and hardness and resistant starch content increased were distinct at a storage of 4℃ for 7 d. Aging ability was stronger for legume starches than cereal starches.Pasting properties of eight kinds of starch were influenced by heat treatment significantly. Peak viscosity and breakdown and setback for aged starches were lower than native starches. The pasting temperature for aged starches of broad bean and pea and mung bean and buckwheat and millet and proso millet starches was higher than their native starch, while barley and waxy proso millet starches were opposite. All aged starches didn’t appear endothermic peak, demonstrating that new composed crystal structure was stable and hardly melted.3. Retrogradation degree of starch gels increased as concentration rose. Broad bean and mung and proso millet starch gels aged easily at 4℃ during storage, while for pea and buckwheat and barley and millet starch gels at-18℃. The increase of pH value decreased hardness and gumminess and chewiness of starch gels. The addition of glucose and sucrose raised starch gel properties, besides, glucose was better than sucrose; The addition of xanthan and konjac gum enlarged hardness; The addition of fumaric acid boosted hardness and gumminess and chewiness remarkably. The addition of glucose and sucrose as well as xanthan and konjac gum promoted freeze-thaw stability; The addition of fumaric acid improved freeze-thaw stability for pea and buckwheat and barley and proso millet and waxy proso millet starch pastes and weakened for mung bean starch paste and had no effect on broad bean and millet starch pastes.