| This paper, based on the analysis of tea polysaccharide(TPS) purified and its physicochemical properties, investigated physical and chemical characteristics, gelatinization, retrogradation, crystallization properties of two flours and their starch, and then systemically analyzed the effect of TPS on gelatinization and retrogradation of two flours and their starch, studied on application of TPS as an additive in bread and cake. Results indicated: 1. The tea polysaccharide purified, analyzed by HPLC, presented a signal peak, and the molecular weight determined is 10~10.5×105g/mol. TPS, possessed the characteristics of polysaccharide peak by infrared spectrometer, solid state 13C CP/MAS NMR and liquid state 13C NMR, was a complex polysaccharide with uronic acids, amino or acidamide radical and comprisedαanomer andβanomer in chains. TPS composed of monosaccharides linked byβ-glycosidic bond. The results showed, analyzed by differential scanning calorimetry and X-diffraction, that TPS contained two polymers or more. The relative crystallinities and endothermic peak increased as purification. The solution was belong to Newton fluid as TPS concentration is lower than 8%, and belong to pseudoplastic fluid as the levels is more 8%. Antimicrobial activities of TPS indicated that the solvent can inhibit Escherichia Coli,Bacillus subtilis,Penicillium sp and no effective inhibition with Candida, Lactobacillus Bulgaricus, as TPS levels is more 1%.2. The average dilatation ratio of cake starch granulars were more than those of bread starch granular by the microscopical determination. The iodine-complexation of amy- loses from two starches were between 19.50 and 20.05, and for amylopectins were 0.08~1.0. The viscosity average molecular weight of bread amylose and cake amylose are 210,000 and 231,000, respectively. The apparent viscosities of cake flour and its starch were more than those of bread flour and its starch by the analysis of rheological properties. All solvents were belong to pseudoplastic fluid. The results of DSC indicated that the peak temperatures of flours were higher than those of their starch, and the enthalpies of flours were below than those of their starch. The retrogradation rates and enthalpies of flour gels were less than those of their starch as storage at 20℃,4℃,-20℃, respectively. However, accelerated retrogradation rate and advanced enthalpy during storage at 4℃. The relative crystallinites of bread starch and its amylose were more than those of cake starch and its amylose, analyzed by X-power diffraction, and crystallization rate of flour gels were lower than those of their starch gels.3. TPS increased the apparent viscosity of bread flour and its starch, and cake flour and its starch. In addition, elevating the gelatinized temperature and increasing enthalpy, all samples were analyzed by DSC. The results after storage at 4℃for 20 days showed that the enthalpy, velocity of retrogradation and glass temperature were enhanced with time. TPS strongly inhibited aging rate, enthalpy, crystallization velocity and improved glass temperature as increasing level. The inhibited effect of TPS on starch gels were larger than those of their flour gels. The effects of TPS on starch, amylose, amylopectin are analyzed by 13C CP/MAS NMR. The results indicated that C-1 and C-6 position in the chain of amylose molecular, and C-1, C-4, C-6 position in the chain of amylopectin molecular were strongly effected by TPS.4. TPS added accelerated the fermenting velocity of dough. 1-3% TPS increased the volume of bread. The bulk of cake is slowly increased with increasing TPS. Bread and cake containing 2% TPS possessed the improved flavor and quality, analyzed by sensory evaluation and texture after storage at 20℃,4℃for 5 days. The results indicated that the enthalpy, aging rate, crystallization velocity were continually advanced during storage at 4℃, analyzed by DSC and X-diffraction, and continually declined with increasing TPS. The results analyzed by GC-MS, indicated that the main aroma components of 60% TPS contained aldehydes, alcohols and absented phenolic compounds. Bread and cake saved octanal, benzeneacetaldehyde, epicedrol, linslool in TPS. Wheat flour containing octanal, benzeneacetaldehyde, Furfural, 2-pentyl-furan, Hexanal were preserved after the addition of TPS. TPS, that added in bread and cake, caused more aroma compounds that mainly included 3,7-dimethyl-1,6-Octadien-3-ol and octahydro-4,8,8,9-tetramethyl-1,4-Methanoazulen -7(1H)-one.
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