The Development of Pumpkin Extrudates and the Study of Its Anti-oxidative Characteristics and Liver Protectve Functions

本研究應用擠壓技術進行南瓜的加工、抗氧化特性及其護肝功能之研究。第一章利用反應曲面法尋求添加南瓜粉於玉米粉中之最佳比例及擠壓機之最適操作條件，開發最佳品質之膨發休閒保健食品。第二章進行南瓜擠壓產品抗氧化功能之研究。以擠壓機最適操作條件之南瓜擠壓產品，評估其抗氧化功能，包括清除DPPH自由基能力、還原力之測定、總抗氧化能力和螯合亞鐵離子能力。另外，亦加入BHA和α-生育醇實驗組為對照組進行抗氧化性之評估。第三章進行南瓜擠壓產品之生理活性之研究，按照健康食品之護肝功能評估方法，把未添加及添加不同比率的南瓜擠壓產品分別餵食正常老鼠及被誘發肝損傷之大鼠，探討大鼠血液中之血糖、三酸甘油脂、膽固醇、肝功能生化指數GOT 及GPT 餵食前後變化情形，又取其肝臟測定抗氧化酵素系統（活性及mRNA）之變化。 第一章之研究已找出南瓜擠壓產品之最適擠壓操作範圍為：螺軸轉速275~288 rpm、進料含水率11.5~12.5%、南瓜粉添加比例19~21%。第二章之研究利用上述四種抗氧化功能測定，皆以純南瓜粉原料效果最佳；南瓜擠壓產品其次；玉米粉擠壓產品最低，且三者間均有顯著差異(P<0.05)。而本研究亦顯示南瓜擠壓產品雖然只有20%的添加比例，卻具有接近於佳純南瓜粉原料之抗氧化功效。第三章之研究顯示在肝損傷老鼠之試驗中，發現攝食南瓜擠壓產品（南瓜粉添加20%組）均可減緩因肝損傷而造成之GOT 或GPT 上升狀態，並可增加SOD 活性及抗氧化酵素的活性表現以代償這項傷害。本研究成果已說明南瓜原料經擠壓加工後仍具有其原來的機能活性。In In this study, a single screw extruder was used to process pumpkin extrudates. The anti-oxidative characteristics and liver protection functions of the extrudates were also studied. Response surface methodology (RSM) was used to investigate the effect of operation condition on the physiochemical properties of a pumpkin extrudates in the first part. In the second part, the antioxidant activities of the extrudates were evaluated by the inhibition of peroxidation rate, DPPH scavenging abilities, reducing power, total antioxidant activity and chelating abilities. Pumpkin powder, corn grits extrudates, vitamin C, vitamin E (α-tocophero) and BHA were used for comparisons. IC50 value is the effective concentration for the antioxidant activities and was obtained by interpolation from linear regression analysis. The third part of this study is to evaluate the physiological activity of the pumpkin extrudes. This study compared the normal and liver damaged rats induced by TAA with pumpkin powder extrudate and normal feeding. The blood sugar, serum triacylglycerol, serum cholesterol, GOT and GPT of the rats were determined. The activity of the anti-oxidative system was also determined by measuring the activity of the SOD and mRNA contents in the livers of the induced rats. In the first part, the regions of the optimum operating conditions were identified at the screw speed of 275~288 rpm, feed moisture content of 11.5~12.5 %, and pumpkin flour level of 19~21 %, respectively. In the second part, according to the results of the four antioxidant properties above, the effects of pumpkin powder were the highest, pumpkin extrudates was the second, and corn grits extrudates had the lowest effects; significant difference shown among these treatments (P