去支鏈酵素處理對不同預煮溫度之糯性米穀粉理化特性和抗性澱粉含量的影響

Effects of debranching enzyme treatment on physiochemical properties and resistant starch content of waxy rice flour with various precooking temperatures

本研究的目的是比較天然糯性米穀粉和經不同預煮溫度與去支鏈處理的米穀粉之理化特性和其回凝樣品之抗性澱粉含量。第一變因為預煮溫度處理，分別於55、65、75 與121 oC進行30 分鐘；第二變因為去支鏈酵素處理時間，分別為1、6、12 與24 小時，以Pullulanase於55 oC 進行。進一步烹煮與回凝4 oC 24 小時。結果顯示與天然米穀粉相比，適當的預煮溫度及去支鏈處理時間之組合條件可增加視直鏈澱粉含量、油結合力、水結合力、溶解度指數和抗性澱粉含量。而考量個別變因，提高預煮溫度可以增加視直鏈澱粉含量、油結合力、水結合力、溶解度指數和抗性澱粉含量。增加去支鏈處理時間可以增加油結合力、水結合力和溶解度指數。隨著去支鏈處理時間增加至12 小時可提高視直鏈澱粉和抗性澱粉至最大量，更長處理時間反而使兩者含量下降。

The objective of the study was to evaluate the effects of debranching time on physicochemicalproperties and resistant starch content of waxy rice flour with various precooking temperatures.The first factor is precooking temperature including 55, 65, 75, 121 oC for 30 min; and the secondfactor is debranching time including 1, 6, 12, 24 h at 55 oC with pullulanase. Further cooking andretrogradation at 4 oC for 24 h made the retrograded debranched rice flour. Results showed thatthe treated samples had the increase in the apparent amylose content (from 0.58% to 7.12-36.32%),oil absorption capacity (from 1.22 g/g to 1.27-2.80 g/g), water absorption capacity (from 2.56 g/gto 2.64-21.00 g/g), water solubility index (from 1.34% to 6.76-45.23%), and resistant starch (from0.66% to 6.63-25.47%) as compared with native rice flour. The higher precooking temperaturemade the treated samples with the higher apparent amylose content, oil absorption capacity,water absorption capacity and water solubility index, and resistant starch. The increase in thedebranching time also made the debranched rice flour with higher oil absorption capacity, waterabsorption capacity and water solubility index. However, the apparent amylose content of the debranched rice flour and resistant starch of the retrograded debranched rice flour increased withthe debranching time up to 12 h, but decreased with the longer debranching time.