使用微波輔助酸修飾生產半結晶性玉米澱粉糊精與其性質

Abstract

實驗目的為利用微波選擇性加熱於澱粉顆粒中非結晶區。以Lintnerized starch為對照組，微波輔助酸修飾不同直鏈澱粉含量之糯性玉米、一般玉米及HylonV。藉微波輔助酸修飾製備具有半結晶性玉米澱粉糊精（amylodextrin），證明澱粉顆粒中非結晶區已被去除。以一般玉米澱粉尋找出水解率類似Lintnerization的微波加熱條件(2N30秒)。利用一般微波加熱器作用於飽和2N HCl 的三種澱粉顆粒(約40%)30秒，生產半結晶糊精。結果顯示Lintnerization 與微波輔助酸修飾中，糯性玉米澱粉破壞程度較一般玉米澱粉高，HylonV比一般玉米澱粉更具酸抗性。由微波輔助酸修飾所產生的微晶化糊精顆粒型態雖依然存在，但分子卻明顯變小。以X-ray圖譜之結晶度變化得知，經由Lintnerization與微波輔助酸修飾，繞射強度有上升或下降的變化，結晶型態並無改變。綜合得知，微波可選擇性的加熱存在澱粉中非結晶區的酸溶液。

The aim of this study is to provide evidences of selective heating of microwave on amorphous region of starch granules. Acid modification assisted with microwave on starch granules was employed as model system and Lintnerized starch prepared from three maize starches with different amylose content, waxy、normal maize、Hylon V maize starch were used as reference. Amylodextrin products with semi-crystalline properties were successfully prepared by microwave assisted acid modification indicating the removal of amorphous region of starch granules. Normal maize starch was used to optimize condition of microwave heating to obtain similar hydrolysis ratio of Lintnerization. It was selected to produce semicrystallin amylodextrin from the three maize starches by heating 2N HCl solution saturated starch granules (about 40% moisture) on domestic microwave heater for 30 seconds. HylonV maize starch granules were the most resistant and waxy starch was less resistant comparing to normal starch both under Lintnerization and microwave assisted acid modification. Amylodextrin produced by microwaving process still remained some starch granules even though their molecular size had been dramatically reduced. The amylodextrin obtained from Lintnerization and microwave assisted acid modification all showed clear x-diffraction pattern with slightly increased or decreased intensity without any pattern changes. These results provided indirect evidences that microwave could select heating on the water-enriched amorphous region of starch granules.