甘藷定溫加熱過程澱粉糖化反應機制研究

Abstract

本研究以不同烘烤溫度(60 oC、70 oC、80 oC、90oC)以及不同烘烤時間(5、10、15、20、25、30分鐘)烘烤甘藷，並分析烘烤甘藷後麥芽糖含量變化情形，並進一步分析溫度對於糖化反應中兩個重要因素─澱粉酶活性以及澱粉糊化程度─的影響。利用Labview系統以及熱電致冷晶片建立的定溫加熱系統提供了快速且穩定的溫度控制，對於需要長時間定溫烘烤的實驗相當有幫助。結果顯示麥芽糖含量在烘烤溫度為60oC時增加的幅度是四個溫度最低的，而最高的則為80 oC；α澱粉酶以及β澱粉活性則是在烘烤過後便呈現衰退的趨勢，但是此趨勢會在經過十分鐘的烘烤後漸漸緩和；澱粉糊化程度實驗結果則顯示當烘烤溫度較低時(60oC)澱粉糊化程度較不顯著，而當烘烤溫度提高到90 oC，即使烘烤時間僅有五分鐘也能夠達到完全糊化。綜合以上實驗結果，推論在甘藷烘烤過程中，澱粉糊化程度對於糖化反應的影響較α澱粉酶以及β澱粉活性大。

The purpose of this thesis was to assess the temperature effect on saccharification reaction. During baking, maltose content of sweet potato is increasing due to saccharification of starch. Saccharification in sweet potato is an amylase reaction on pasted starch and baking temperature and time are key factors that influence the final content of maltose. Heating will increase degree of starch pasting to favorite saccharification but also the deteriorate activity of amylase. In this study, we developed a constant temperature heating apparatus, which is is monitored by the plate thermal couples and the temperature is controlled by PID controller written in Labview software, for heating sweet potato slice. Under the well-controlled process, a better temperature-time relationship of saccharification will be understood. In the experiment, baking temperatures are controlled from 60°to 90°C in 10°C difference and durations of heating are from 5 to 30 minutes in 5 minutes difference. Results show that the highest maltose conversing was observed at 80°C. On the other hand, activity of amylase decrease after 5 minutes baking but the decreasing trend become smooth after 10 minutes. Furthermore, when baking temperature becomes higher, the degree of pasting starch become higher even with short baking time. In conclusion, the degree of pasting starch is more influential than the activity of amylase in saccharification reaction during baking.