| As a major component of Castanea henryi, starch is rich in several kinds of nutrition, and also affects processing characteristics and nutritional quality of Castanea henryi. This paper mainly studied physical and chemical properties of Castanea henryi starch as well as factors that have effect on starch paste retrogradation and methods of anti-retrogradation. Also, the processing technology of microwave puffing Castanea henryi flaky pastry was studied according to market needs. The results of the research are summarized below:1 Study of physical and chemical properties of Castanea henryi starchAmylose content is 27.50 % of total Castanea henryi starch. The relative density and the white degree of Castanea henryi starch is respectively 1.31 and 63.The crystalline structure of Castanea henry istarch possesses'C'XRD pattern. And the starch granule has smooth surface, elliptic shape mostly, few of them was round or irregular. The granule has obvious polarization cross ring veining and has a range 0.8μm～13.7μm with hilum locating at the midpoint.According to the mensuration Castanea henryi starch paste is with lower clarity, lower freeze-thaw stability and lower gel intensity. The solubility and swelling power increase as temperature grows, but solubility increases slowly. Castanea henryi starch is a restrictive swelling starch because the swelling power is lower.The changes of viscosity of Castanea henryi starch paste with different addictives were studied by Brabender viscosity instrument. The results showed that the initial gelatinization temperature of Castanea henryi starch was 64.8℃. The gelatinization temperature and the viscosity-peak of Castanea henryi starch increase with addition amount of sucrose, salt and NaHCO3 while the retrogradation decreased with it. And the viscosity and retrogradation of Castanea henryi starch increased under both of acidic condition (pH=4) and alkali condition (pH=10). However, the relatively litmusless condition (pH=6 or pH=8) would hardly affect the viscosity-peak and initial gelatinization temperature. The temperature changes had great influence on viscosity of Castanea henryi starch with or without different factors.2 Study of Castanea henryi starch paste retrogradation and restraining methodsCastanea henryi starch paste got retrogradation so easily at the temperature of 4℃that retrogradation rate had reached 9.76% after 24 hours. Also it can be seen from the research that Castanea henryi starch easily got retrogradation under the condition of both pH5 and pH7 against both pH3 and pH9. Addiction amount of both 3.0g/100mL and 6.0g/100mL of sucrose had a significant effect on starch retrogradation rate. Starch retrogradation would be mitigated or even inhibited when the addiction amount reached both 9.0g/100mL and 12.0g/100mL. Meanwhile, adding salt could mitigate or inhibit starch retrogradation, but there existed no difference between addiction amounts.The study of effectiveness of different addiction amounts of six addictives on inhibiting Castanea henryi starch retrogeadation showed that all addictives were effective. The comparison between six addictives of their effectiveness on inhibiting Castanea henryi starch retrogeadation with their minimum quantities showed that GMS achieved best effect, followed by SSL, trehalose, CSL, SE and DATEM.Through L16(45) orthogonal experiment, the optimal compound formula for inhibiting Castanea henryi starch retrogeadation was as followed: 0.35g/100mL GMS , 0.30g/100mL SSL , 0.45g/100mL CSL and 0.20g/100mL SE.3 Study of processing technology of microwave puffing Castanea henryi flaky pastryBy analyzing and studying of basic materials and processing technology of microwave puffing Castanea henryi flaky pastry, using puffing degree, hardness and comprehensive sensory evaluation as index, through single factor analysis and L9(34) orthogonal experiment, the optimal basic ingredient of microwave puffing flaky pastry was determined as: 50% Castanea henryi powder(That is ,in every 100g of raw material powder, the ratio of Castanea henryi powder to flour was 1:1), 25.0g shortening oil, 25.0g sucrose, 3.0g salt, 1.5g NaHCO3, emulsifier(0.35g GMS, 0.30g SSL, 0.45g CSL and0.20g SE ) and the moisture content of the Materials was 20%. This optimal combination could help Castanea henryi flaky pastry obtain best puffing degree, crisp, color, taste and flavor.The optimal basic processing technology parameter of microwave puffing Castanea henryi flaky pastry was determined as: Castanea henryi powder passed 100 mesh; kneading and mixing time of dough for 10 min; 3.0mm for dough thickness, microwave puffing power for 800w and puffing time for 3min.
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