國產紫心甘藷生粉、熟粉及澱粉之理化性質與回凝特性比較

Comparing Physicochemical Properties and Retrogradation Characteristics of Uncooked Powder, Cooked Powder and Starch from Domestic Purple Sweet Potato

黃筱筑(Hsiao-Chu Huang) ； 江伯源(Po-Yuan Chiang)

《臺灣農業化學與食品科學》 55卷3&4期 (2017/08) Pp. 121-132

https://doi.org/10.6578/TJACFS.201706_55(3&4).0001

摘要

甘藷為台灣重要糧食作物之一，具有食糧、飼料，加工原料等用途，104年全國生産量高達23萬公噸，常見之食用品種為台農57號（TN57），台農66號（TN66）及台農73號（TN73），其中TN73含有高量花青素具抗氧化功用，且烹煮後肉色艷麗，可做為鮮食，餡料加工等用途，乃是國人喜愛之營養，美味農作物，本試驗比較紫心甘藷之生粉，熟粉及澱粉之理化性質及回凝特性的差異，試驗結果如下：不同粉類之成糊性質黏度值由大至小為澱粉＞生粉＞熟粉，熟粉相較於生粉無明顯的糊化圖譜，而相較於澱粉生粉數值皆明顯下降，尖峰黏度自5411 cP下降至574 cP：熟粉，生粉及澱粉粒徑D50分別為84.51μm，22.27μm及14.86μm；生粉及澱粉膨潤力溶解度皆隨時間增加，在溫度超過75℃後會大幅上升，和55℃下比較TN73生粉溶解度自16.68％增加至39.71％。澱粉溶解度自0.39％增加至6.95％，與RVA糊化溫度結果相符：觀測回凝性質，在4℃下貯放7天後澱粉硬度明顯升高而粘性下降，生粉貯存硬度和澱粉相同呈逐漸升高，但黏度結果相反亦隨時間增長而上升，熟粉則無顯著質地改變；以掃描式電子顯微鏡觀察回凝過程變化，澱粉網狀構造呈孔洞增大，生粉及熟粉由片狀結構逐漸呈現不規則網狀構造，希盼本試驗初步結果可作為甘藷生熟粉應用或開發為相關即食沖泡飲品之應用與參考。

關鍵字

台農73號 ； 生粉 ； 熟粉 ； 澱粉 ； 回凝

並列摘要

Sweet potato is one of the major food crops in Taiwan, with food, feed, processing and other uses of raw materials. It have been reported that 104 annual production capacity was up to 230,000 tons. Tainung 57 (TN57), Tainung 63 (TN66) and Tainung 73 (TN73) are common varieties of sweet potato in Taiwan, which TN73 contains a high amount of anthocyanin with antioxidant function, showing bright color after cooking and can be used as fresh food, filling and other purposes. Being the food which is popular and contains much nutrients. In this experiment, the differences of physical and chemical properties and retrogradation characteristics of uncooked powder, cooked powder and starch of purple sweet potato were compared. The results of the test are as follows: peak viscosity, final viscosity and setback viscosity of different powders arranged from large to small are starch＞uncooked powder＞cooked powder. and the result of cooked powder is not obvious compared with the raw powder. Compared with the starch, viscosity values of uncooked powder significantly decreased, such as the peak viscosity from 5,411 cP down to 574 cP. The solubility and swelling power of uncooked powder and starch are increased with time and increased significantly after the temperature exceeded 75℃. Compared with 55℃, from 16.68% to 39.71% solubility increase and starch solubility increase from 0.39% to 6.95%, presuming that starch gelatinization attribute for the changes and is consisted with the results of gelatinization temperature in RVA tests. Observing the properties of retrogradation at 4℃ after 7 days, the hardness of starch increased obviously and the viscosity decreased. The storage hardness of uncooked powder increased gradually with the same upward trend in starch. However, the results showed that adhesiveness of uncooked powder was increased with the increase of time. There is no significant texture change in cooked powder. Under the observation of scanning electron microscopy, the starch network is hardened and the pore becomes larger. The structures of uncooked powder and cooked powder changed from flaky structure to irregular network. The preliminary results of this trial can be used as a sweet potato flour application or development for the relevant ready-to-eat beverage.

並列關鍵字

TN73 ； Uncooked Powder ； Cooked Powder ； Starch ； Retrogradation