利用蝶豆花開發機能性膨發米點心之研究

蝶豆花富含許多機能性成分包含: 酚酸、類黃酮、花青素、三帖類化合物以及類固醇等，而蝶豆花的花青素能夠提供鮮豔色彩且具有良好清除自由基的能力，可作為一種天然色素及抗氧化素材。多項研究表明蝶豆花花青素具較高的熱穩定性，可承受一般食品工業上之熱加工處理。而擠壓膨發食品為一相當普遍且受歡迎的休閒點心食品，具有口感脆，呈多孔狀組織，且輕巧及同重量下具有較大體積等特性。擠壓膨發技術，具有高效能、高品質、多樣化等優點。因此，本研究目的為利用蝶豆花良好的熱穩定性、顏色多樣性及良好的抗氧化性質，添加於糙米中，並搭配膨發擠壓之高溫短時加工技術，欲保留較佳的色素及抗氧化性質，進行（3x3x3）複因子膨發擠壓試驗，以不同比例蝶豆花（0、5、10 %）、螺軸轉速（320、350、380 rpm）與模具溫度（110、120、130℃）探討最佳加工條件。研究結果顯示，蝶豆花添加比例的增加會使擠出物的水溶性指標及徑向膨發率顯著下降，同時顯著（p<0.05）提升擠出物之假密度、吸水性指標及抗氧化性質，且其抗氧化性質能夠因適當的提升模具溫度而顯著（p<0.05）上升，在添加10%蝶豆花下，模具溫度120℃及螺軸轉速350 rpm時，擠出物有最高的總酚含量537.32 ppm；而在相同的模具溫度下，提升螺軸轉速至380 rpm有最高的DPPH清除自由基能力77.16%及還原力0.140。經最佳操作條件之選定與評估後，在0%、5%及10%蝶豆花添加下各挑選一組擠出物進行感官品評試驗，研究結果顯示，添加5%蝶豆花之擠出物雖具有最好的接受度但卻與10%蝶豆花添加之擠出物無顯著差異，且10%蝶豆花添加之擠出物具有最佳的抗氧化性質，因此，在10%蝶豆花添加、模具溫度120℃、螺軸轉速380 rpm為本研究之最佳研究結果。

關鍵字

蝶豆花；米；擠壓技術；膨發點心；抗氧化

並列摘要

Clitoria ternatea is rich in many functional ingredients including: phenolic acid, flavonoids, anthocyanins, triterpenoids and steroids. The anthocyanin of Clitoria ternatea can provide bright colors and good antioxidant capacity which can be the natural pigments and antioxidant materials. A number of studies have shown that the anthocyanins of Clitoria ternatea have good thermal stability that can withstand the thermal processing in the general food industry. Extrusion food is a common and popular snack food, which has crisp texture, porous structure, light and has a large volume under the same weight. The advantages of extrusion technology are high efficiency, high quality and variety. Therefore, the purpose of this study is to develop a brown rice snack added with Clitoria ternatea. And processing by collet extruder which is a high temperature low time (HTST) techonology to protect the color and antioxidant properties. The study is designed by (3x3x3) complex factor with different proportion of Clitoria ternatea (0%、5%、10%), screw speed (320, 350, 380 rpm) and die temperature (110, 120, 130°C). The results showed that when the proportion of Clitoria ternatea increased, the water soluble index (WSI), and the radial expansion ratio would be decreased, whereas the bulk density, water absorption index (WAI) and antioxidant properties would be significantly increased. The antioxidant properties could be appropriately raised up significantly while the die temperature was increased. Under the addition of 10% Clitoria ternatea, the highest total phenols content was 537.32 ppm at die temperature 120°C and screw speed 350 rpm. At the same die temperature, when screw speed was increased to 380 rpm, the extrudates has the highest DPPH scavenging ability 77.16% and reducing power 0.140. After optimum operating conditions of selection and evaluation, the extrudates were selected for each of the 0%, 5%, and 10% Clitoria ternatea addition for sensory evaluation test. The results showed that the extrudates of 5% Clitoria ternatea addition are the most acceptable but not significantly different with the extrudates of 10% Clitoria ternatea addition which have the best antioxidant properties. When the die temperature 120°C and screw speed 380 rpm is the optimum processing conditions for the extrudates of 10 % Clitoria ternatea addition.