| The particle properties, rheological properties, gelatinization and Pasting properties of chestnut starch were studied by dynamic rheometer, rapid viscosity analyzer, differential scanning calorimetry, scanning electron microscopy (SEM) and other methods, and have further explored the processing parameters of water chestnut starch.1. starch from water chestnut was extracted by repeatedly water washing. Observed with SEM, the granules had two kind of shape:oval and polygon; the particle size was from 5 to 30μm.2. the content of starch amylose,and non-soluble amylose of water chestnut was 15.88%and 28.01%.the hydratability was 2.01g/g.3. Measuerd with rapid viscosity analyzer, the gelatinization temperature of chestnut starch was 81.7℃-88.6℃. DSC(Differential Scanning Calorimetry) spectrum shows that the gelatinization temperature of chestnut starch was 79.5℃-87.3℃. respective the gelatinization temperature of chestnut starch was from 87.1℃to 83.0℃with dynamic rheometer.4. The result of freeze thaw stability experiments showed that the water chestnut starch paste was non-Newtonian pseudoplastic fluid and had weak freeze thaw stability and prone to have the phenomenon of shear thinning. NaCl and monoglyceride can make shear stress of the paste decreased, the viscosity decreased slightly and hysteresis area increased; xanthan gum and cellulose can make shear stressand viscosity of the paste ignificantly increased, while little changed in hysteresis area. It is showed during dynamic rheological analysis of water chestnut starch that G'and G" changed significantly in the peak.5. By measuring the turbidity of starch, retrogradation properties and thermal characteristics during storage analysis, water chestnut starch showed fast short-term retrogradation and the overall regenerative ability. After 24h storage,the percentage of retrogradation (R%) was 11.76.6. The main factors of the Process engineering in the water chestnut:the water content and the starch paste content in the modulation process, the freezing temperature, retrogradation time, freeze time in the process of frezzing. Through the analysis of dough thixotropic curves, in accordance with hysteresis loop area of the thixotropy curve and the actual production process parameters, the best result of the dough was determined:water content 45%, the amount of 5% thickening:holding temperature of 30℃or room temperature. By orthogonal experimental method to study the freezing temperature, freezing time and aging time on the quality of noodles, the freezing temperature was the most critical factor in the quality, followed by aging time. the best conditions showed:a good pasting noodles, aging for 6h at 4℃,and freezing for 6h at -2℃7. By comparative evaluation of water chestnut noodles and mung bean noodles, the chestnut noodles had the smaller loss of boiling water better transparency, but the worse breaking rate, tensile strength and shear deformation than mung bean noodles.8. By adding other types of starches to improve the quality of the noodles quality, Two aspects has been studied,one is the types of the added starch,the other is the proportion of added starch adding mung bean starch was better than sweet potato starch. The proportion of added starch was 50% of the mung bean starch mixed with 50% of the water chestnut starch as thickening paste, by which the breaking rate decreased from 2-3 to 0-1, while the shear deformation increased by which the breaking rate, the tensile deformation increased from 0.22 to 0.32. |
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