The Influence Study Of Superfine Grinding On The Physicochemical And Processing Properties Of Castanea Henryi Powder

The seeds of Castanea henryi are rich in starch and sugar, while rich in fats, proteins, amino acids, vitamins, and ascorbic acid, carotene and other substances.In this paper,Castanea henryi produced in Fujian province was used as the material in the research and dried in three methods(hot air drying,vacuum drying,freeze-drying).Then the product was pulverized to Castanea henryi superfine powder.And its physical and chemical properties were explored.Furthermore,the application on bread depending on the theoretical foundation were also studied.The results are as follows.Firstly,the process exploration of the Castanea henryi ultrafine grindingAfter the fresh shelled Castanea henryi was cut to sheet slice,the complex combination of 0.14% (mass fraction) citric acid,0.20%EDTA-2Na,0.5% NaCl,0.03% Vc were used for the color protection treatment.Furthermore,hot air drying, vacuum drying,and vacuum freeze-drying were chose for drying treatment.Finally it was pulverized in the superfine grinder more than 200 mesh.In the single-experiments,factors including speed of main engine rotating speed,wind speed and amounts of rough Castanea henryi powder were done in the research.And the conditions which were rotating speed,wind speed and amounts of rough Castanea henryi powder were 35Hz,32Hz and 800g.Then three factors three levels orthogonal experiments based on the single-experiments, with factors including rotating speed(32Hz,35Hz,38Hz),wind speed(29Hz,32Hz,35Hz) and amounts of rough Castanea henryi powder(750g,800g,850g) were also done. The two groups of experiments mentioned above showed that the optimal main engine rotating speed,optimal wind speed and optimal amounts of rough Castanea henryi powder are 38Hz,35Hz and 800g respectively.Under this condition, the yield rates of ultra-micro Castanea henryi powder above 200 meshes were 92%.Secondly,the influence of superfine on the physical and chemical properties of ultra-micro Castanea henryi powderThere were certain influence to ultra-micro Castanea henryi powder on its physical and chemical properties after the ultra-fine grinding treatment.The research showed that:the bulk density of superfine powder though freeze drying was the largest one.and the bulk density of superfine powder though hot air drying was the least one.Bulk density after the vacuum drying and the freeze-drying process had little difference between each other.The surface structure of ultra-micro Castanea henryi powder observed with scanning electron microscope is partially worn and rough. The shape of the granule is partially elliptical,but some is irregular.The two drying methods,hot air and vacuum,had little difference in the shape of granule magnified 2000 times.The shape of freeze-dried granule is more regular than the previous two ways.Under the same temperature conditions, the solubility in order from the biggest to the smallest isrfreeze-drying,vacuum drying,hot air drying.The water-retaining capacity(WRC) in order from the biggest to the smallest is:freeze-drying,hot air drying,vacuum drying.With the increase of temperature, the water-retaining capacity of the granule dried though the three methods also increases gradually.For freeze-thaw stability, the same freeze-thaw cycles, the water separating proportion in order from the biggest to the smallest is:hot air drying,vacuum drying,freeze-drying.The result showed that:freeze-thaw stability of the Castanea henryi ultrafine powder dried though freezing method is the best one.The gelatinization process of Castanea henryi ultrafine powder which began about 66℃is an endothermic.The peak temperature and peak viscosity in gelatinization process is not identical, and the order from the biggest to the smallest is.vacuum dried granule,Castanea henryi starch,hot air dried granule,freeze-dried granule.Thirdly, study of the baking characteristics of Castanea henryi superfine powder on breadThe raw materials of Castanea henryi superfine powder bread were studied by the index of sensory score and hardness score.The raw materials,such as Castanea henryi superfine powder 18%,yeast 1.84%,bread improver 0.2%,sugars20%,salt 1%,egg10%,milk powder 5%,oil 8% and water 50%,were proved to be the best by single-experiments and quadratic orthogonal regression rotation combination design experiments.The flavor, taste and color of the bread Obtained under this condition was best.The resistant starch content measured in Castanea henryi superfine powder bread is 26.9% which was 3.3% higher than the general bread. The result also showed that the content of resistant starch increased though the superfine treatment.It is beneficial to human healthy.