Study on the Physicochemical Properties and Ready-to-eat Characterics of Wheat Flour with Different Treatment of Drum Drying (Pregelatinized)

Abstract

即食穀粉具有沖泡即食（ready-to-eat）之特性，近年廣受消費者所喜愛，市場潛力大。本實驗探討滾筒乾燥對冷、熱漿－小麥麵粉理化性質及沖泡特性之影響。實驗結果如下：熱漿預糊化處理小麥麵粉，因加熱時間較長，其粉末呈為黃色。另在尖峰黏度、最終黏度、黏度裂解值、黏度回升值項目中，冷漿預糊化處理均較熱漿樣品高；冷漿樣品粒徑較小，糊化片狀物呈多孔黏稠狀，膨潤力大、溶解度及離層性則較熱漿樣品小。兩種滾筒預糊化處理之粉末其十字偏光及X-ray繞射波峰均呈消失變化，糊化度均達100%，以85℃預糊化5 min可得到較佳離層安定性。

Due to its ready-to-eat characteristic, instant flour is widely preferred by consumers and has great marketing potential. This study examines the influence of cold and hot slurry feed on physicochemical and ready-to-eat properties of the wheat flour pregelatinized by drum-drying. Results are as following: The pregelatinized hot slurry of wheat flour, because of its long heating time, became slightly yellow. Different kinds of viscosities such as peak viscosity, final viscosity, break viscosity and setback viscosity were also compared, and the results showed that the cold slurry had higher value than hot slurry feed. Cold slurry had a smaller particle size and greater swelling power, but the WSI and separation ratio are lower than hot slurry. The drum-dried pregelatinization of the two samples, cold and hot slurry, could be grounded into powder, their polarized light photomicrographs and X-ray diffraction peak were not detected, showed that gelatinization had reached to 100%. The hot slurry can get a better separation ratio when pregelatinized for 5 minutes at 85℃.