破損米澱粉之理化特性及組織形態分析   全文下載

Physicochemical and Morphological Analyses on Damaged Rice Starches

本實驗係採用台農秈19號（秈米）及台中糯70號（糯米）米澱粉為試驗材料，探討球磨處理對破損米澱粉理化特性之影響。連續糊化黏度分析顯示，在同一球磨時間下，台農和19號之成糊溫度、最高黏度、崩壞度及最終黏度之下降程度皆較台中糯70號米澱粉顯著，相似之現象亦見於示差掃描熱分析之糊化尖峰溫度、吸熱焓值及X-ray繞射分析之波峰強度。然而，兩品種米澱粉之粒徑中央值，卻皆隨球磨時間增長而顯著升高（p<0.05）。偏極光顯微觀察發現破損澱粉失去十字複曲折性，顯示其澱粉顆粒結構受到破壞並破損。掃描式電子顯微結果顯示，球磨處理後米澱粉顆粒變形且表面較粗糙，並會相互聚集而使粒徑增大，兩品種皆然。整體而言，台農秈19號米澱粉之理化特性及顆粒結構受球磨處理之影響較台中糯70號為大。

Two types of rice cultivars, indica type (Tainung Sen 19, TNuS19) and waxy (Taichung Waxy 70, TCW70) were used as samples to investigate the changes in the physicochemical properties of damaged rice starch by ball-milling treatment. Rapid Visco Analyzer (RVA) analysis indicated that onset temperature (To,η), peak viscosity (P), setback (C-H), and cold-paste viscosity (C) decreases were more pronounced in TNuS19 than in TCW70 starch during the ball-milling treatment. Similar phenomena were also found in peak temperature (Tp) and enthalpy changes (ΔH) by differential scanning calorimetry (DSC), and the peak intensities measured by X-ray diffraction. However, both types of starch showed that extended treatment time resulted in higher median particle size (PS 50). Polarized light micrographs showed that damaged starch granules lost their birefringence, suggesting that the order structure of starch granule was disrupted. The morphological changes in the microstructure of rice starch during ball-milling treatment was also examined by scanning electron microscopy (SEM). The results indicated that TNuS19 starch granules may be more susceptible to mechanical action than TCW70 starch. 本實驗係採用台農秈19號（秈米）及台中糯70號（糯米）米澱粉為試驗材料，探討球磨處理對破損米澱粉理化特性之影響。連續糊化黏度分析顯示，在同一球磨時間下，台農和19號之成糊溫度、最高黏度、崩壞度及最終黏度之下降程度皆較台中糯70號米澱粉顯著，相似之現象亦見於示差掃描熱分析之糊化尖峰溫度、吸熱焓值及X-ray繞射分析之波峰強度。然而，兩品種米澱粉之粒徑中央值，卻皆隨球磨時間增長而顯著升高（p<0.05）。偏極光顯微觀察發現破損澱粉失去十字複曲折性，顯示其澱粉顆粒結構受到破壞並破損。掃描式電子顯微結果顯示，球磨處理後米澱粉顆粒變形且表面較粗糙，並會相互聚集而使粒徑增大，兩品種皆然。整體而言，台農秈19號米澱粉之理化特性及顆粒結構受球磨處理之影響較台中糯70號為大。