Effect of extrusion on the lycopene composition and bioactivity of extrudates

擠壓為食品業界中經常使用的加工技術之一，與其他加工技術相比，擠壓加工過程為一高溫高壓的環境，在作業過程中包含了混合、剪切、輸送、蒸煮、擠壓等操作，往往會使物料在擠壓機中產生化學及結構上的變化。蕃茄紅素則為蕃茄中主要的紅色色素，目前已知具有抗氧化、抗癌及預防心血管疾病發生等生理活性。許多的文獻指出，反式蕃茄紅素在經過高溫加熱後，會產生異構化的現象而形成順式蕃茄紅素，因而提升了他的生物可利用率及抗氧化活性。 本研究使用了玉米粉、大豆粕與乾燥後之蕃茄渣做為原料，並以擠壓加工時的套桶溫度、螺軸轉速與物料水分含量作為獨立變因，分析不同產品中蕃茄紅素的組成、理化性質、抗氧化活性及抗癌活性，以瞭解擠壓加工對產品中蕃茄紅素的影響。 研究結果顯示，順式蕃茄紅素的比率會隨著套桶溫度、螺軸轉速的提升及水分含量的降低而有顯著的增加，由蕃茄紅素的組成及產品理化性質分析的結果，得知在高套桶溫度(180℃)、高螺軸轉速(200 rpm)及低水分含量(12-14%)的操作條件下，產品中順式蕃茄紅素的比率較高，且可得到一膨發率佳、比容積大及口感爽脆之產品。而在產品抗氧化性的分析結果得知，在經過適當操作條件的擠壓加工後，確實會使得產品的抗氧化活性獲得顯著的提升 (P < 0.05)。此研究結果顯示，擠壓加工確實能夠使原料中的反式蕃茄紅素轉變為順式蕃茄紅素，並可藉此生產出具有較佳生物可利用率及生理活性之機能性擠壓產品。Extrusion is a popular process in the food industry. It is the combination of blending, shear cutting, steaming, pressing and sterilizing in the barrel tube, thus resulting the molecular transformation and chemical reaction of the raw. Lycopene, the major pigment of tomatoes, have a lot of bioactivities, such as antioxidant, anticancer and anti-atherosclerosis activities. Previous studies showed that thermal process could facilitate the isomerzation of all-trans lycopene into many types of cis-lycopene and thus increase its antioxidant activity and bioavailability. In order to understand the effect of extrusion on the lycopene, this study utilized extruder to process the corn flour, soybean meal (SBM) and dry tomato pomace. We used barrel temperature, screw speed, and moisture content as independent factors, and then analyzed the lycopene composition, physical properties, antioxidant and anticancer ability of extrusion products. Our results showed that extrusion could improve the cis lycopene rate of products. And the cis lycopene rate would increase when the increasing barrel temperature and screw speed and decreasing moisture content. Under the high barrel temperature (180℃), high screw speed (200 rpm) and low moisture content (12-14%) process condition, we can get a high cis lycopene rate, high expansion rate, and good texture product. Extrusion process also could enhance the antioxidant activity of products. These results suggest that extrusion process could improve the isomerzation of lycopene and thus produce extrudates with better bioavailability and bio-functions