| In this paper, castanea henryi as the raw materials, castanea henryi resistant starch as the main object of study, microwave radiation as the modified manner, response surface method was used to study the optimum conditions of microwave power, microwave time, different drying methods, drying temperature, drying time, etc. for the formation of castanea henryi resistant starch. And study the three different drying methods’ effects of castanea henryi powder for solubility, swelling degree, transparency, retro gradation, freeze-thaw stability, crystal structure, particle characteristics, etc. At last the processing of high resistant starch content of castanea henryi instant was researched. The main research results were as follows:(1)Castanea henryi was used as the raw material to prepare castanea henryi resistant starch by the treatment of microwave in combination with three different drying methods. Using response surface analysis the microwave output power, microwave time, drying temperature and drying time’s influence to the resistant starch content. The results showed that:microwave irradiation power and time, vacuum drying time and temperature had a significant effect on the castanea henryi resistant starch content. It was concluded that the optimum preparation process:Microwave output power was 400W, microwave processing time was 4.20min, vacuum drying time was 21.2h, vacuum drying temperature was 57.9℃,in this condition, the castanea henryi resistant starch content was 6.67 g/100 g.Microwave radiation effected castanea henryi starch’s external appearance and internal structure to some degree. Starch molecule chain breaked and some polymerization was reduced, the amylose and amylopectin starch molecular ratio increased which changed the castanea henryi starch physical and chemical properties which effected of castanea henryi powder’s all the physical and chemical properties. The experiment showed that microwave treatment can change the thermodynamic properties of starch; reduce the solubility and swelling power, but the freeze-thaw stability enhancement, iodine blue value and coagulation sink increase.Microwave radiation can significantly increase the content of castanea henryi resistant starch across physical degeneration. By simulating gastrointestinal environment, castanea henryi power was digested by artificial gastric juice and intestinal juice. By comparing the hot air drying system of castanea henryi powder’s digestibility, the microwave radiation increased the digestibility of castanea henryi powder. But the digestive rate of the three kinds of powder obtained by microwave radiation combined with drying was:microwave-freeze drying> microwave-hot air drying> microwave-vacuum drying, which means castanea hemyi resistant starch with good resistance to digestion.(4)Castanea henryi was used as the raw material to prepare the high resistant starch instant castanea henryi by the treatment of microwave radiation. Using response surface analysis the microwave output power, microwave time and immersion time’s influence to the appearance, aroma, taste, texture and so on. The results showed that:microwave output power and time, immersion time had a significant effect on overall evaluation of castanea henryi.It was concluded that the optimum preparation process:microwave output power was 480W, microwave processing time was 3.80min and immersion time was 13.2h.In this condition, the overall evaluation of instant castanea henryi was 9.8. |
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