臺灣博碩士論文加值系統

共軛亞麻油酸(conjugated linoleic acid, CLA)是指一群含有共軛雙鍵的亞麻油酸異構物。CLA主要是存在於反芻動物的肉或乳汁中，而且不易受到加工或儲藏條件所影響。CLA的抗癌效果雖然已經被證實，但其機制仍未清楚，至於CLA的抗氧化能力，則目前仍具有相當爭議性，所以有必要進一步探討CLA對不同種類的模式油的抗氧化能力。此外，CLA與模式油於加熱和光照反應過程中的交互作用亦不明瞭。本研究的目的在於(1)探討共軛亞麻油酸甲酯和模式油於加熱和光照反應中的交互作用；(2)比較共軛亞麻油酸甲酯和模式油於加熱和光照反應中的安定性；(3)探討共軛亞麻油酸甲酯對不同種類模式油的抗氧化作用。
結果顯示，以氣相層析法同步分離共軛亞麻油酸甲酯與模式油的最佳分離條件為：注射器使用不分流模式，溫度200 ℃；烘箱溫度控制為50 ℃維持一分鐘後，以20 ℃/min昇溫至180 ℃維持30分鐘；攜帶氣體為氦氣，流速1.1 mL/min；偵檢器溫度240 ℃，以火焰解離偵檢器偵測。
共軛亞麻油酸甲酯與三種模式油的安定性大小為methyl stearate (MS) ＞ methyl oleate (MO) ＞ methyl linoleate (ML) ＞ methyl conjugated linoleate (MCLA)，其安定性與油脂之飽和程度有關，含雙鍵數愈多則愈不安定。而在大多數的處理組中，MCLA可能促進模式油的裂解或是效果不顯著，但在少數的處理組中，MCLA有緩和模式油的裂解。
添加MCLA對模式油裂解之影響在100及200 ℃加熱時不明顯，但在150 ℃加熱時，模式油的裂解速率會隨著MCLA的添加百分比增加而增加。在過氧化價的變化方面，加熱條件較溫和時，模式油的過氧化價呈持續上升的趨勢，且隨著MCLA添加百分比增加而增加；隨著加熱條件逐漸加劇，樣品之過氧化價呈現先升後降的趨勢，此時MCLA的添加對其過氧化價並無明顯之影響。
光照組別的過氧化價會較加熱組別高，而添加MCLA對模式油的光氧化並沒有顯著之影響。整體看來，MCLA在本實驗的模式系統中並不具有抗氧化之特性。

Conjugated linoleic acid (CLA) belongs to a group of octadecadienoic acids that contain two conjugated double bonds. CLA is present in meats and dairy products of ruminants origin, and is stable under various processing and storage conditions. Several studies have shown that CLA possesses anticarcinogenic properties, however, the mechanism is still unclear. Also, the antioxidant activity of CLA remains controversial. Thus, it is necessary to study the antioxidant activity of CLA towards the various model lipids. In addition, the interaction between CLA and model lipids during heating and illumination remains unknown. The objectives of this study are to: (1) investigate the interaction between methyl conjugated linoleate and model lipids during heating and illumination; (2) compare the stability of methyl conjugated linoleate and model lipids during heating and illumination; and (3) evaluate the antioxidant activity of methyl conjugated linoleate towards the model lipids.
Results showed that the optimum conditions for the separation of MCLA and model lipids consisted of a splitless injection system with helium as carrier gas at a flow rate of 1.1 mL/min. Oven temperature was programmed at 50 ℃, held for 1 min, then increased to 180 ℃ at a rate of 20 ℃/min, and held for 30 min. Injector temperature was 200 ℃. Detector temperature was 240 ℃. MS showed the highest stability, followed by MO, ML and MCLA. The stability of each sample could be associated with the degree of unsaturation. Model lipids with high degree of saturation or with low temperature treatment was able to retard the degradation of MCLA. In most cases, MCLA either facilitated degradation of model lipids or had no effect. In other cases, MCLA was able to retard the degradation of model lipids during heating.
At 100 and 200 ℃ heating, the effect of MCLA on the degradation of model lipids was not pronounced. However, the degradation rate of model lipids increased with increasing MCLA levels at 150 ℃. The peroxide values of model lipids increased with increasing levels of MCLA at low temperature. At high temperature, the peroxide values of model lipids increased initially and then declined afterwards, and, meanwhile, the addition of MCLA did not show significant influence.
The peroxide values of samples under light storage were higher than those under heating, and the addition of MCLA did not show significant effect on the peroxide values of model lipids during illumination. In this study MCLA did not show significant antioxidant ability against lipid oxidation.

目 錄
頁次
第一章 緒言………………………………………………………1
第二章 文獻回顧…………………………………………………4
一、共軛亞麻油酸的簡介及來源………………………………4
1. 共軛亞麻油酸在肉品及乳汁中的含量……………………4
2. 共軛亞麻油酸在乳製品中的含量…………………………7
3. 人體中共軛亞麻油酸的來源………………………………15
二、加工方法對食物中共軛亞麻油酸含量的影響……………15
1. 加工方法對肉品中共軛亞麻油酸含量的影響……………16
2. 加工方法對乳製品中共軛亞麻油酸含量的影響…………19
三、共軛亞麻油酸的生理功效…………………………………21
1. 共軛亞麻油酸於動物試驗之生理功效……………………21
2. 共軛亞麻油酸於細胞培養試驗之生理功效………………31
四、共軛亞麻油酸的抗氧化能力………………………………40
1. 共軛亞麻油酸於模式系統中之抗氧化能力………………40
2. 共軛亞麻油酸於動物體內之抗氧化能力…………………44
3. 共軛亞麻油酸抗氧化能力之反證…………………………47
五、共軛亞麻油酸的分離與鑑定………………………………58
六、油脂的氧化…………………………………………………60
第三章 材料與方法………………………………………………66
一、實驗材料……………………………………………………66
二、儀器設備……………………………………………………67
三、實驗流程……………………………………………………68
(一)加熱處理…………………………………………………68
(二)光照處理…………………………………………………69
(三)以氣相層析法同步分離共軛亞麻油酸甲酯
異構物及模式……………………………………………71
(四)以氣相層析儀分析各脂肪酸甲酯的殘留量……………72
(五)模式油於加熱和光照中之裂解速率測定………………74
(六)POV (peroxide value)的測定…………………………75
(七)統計分析…………………………………………………78
第四章 結果與討論………………………………………………79
一、以氣相層析法同步分離共軛亞麻油酸甲酯
異構物與模式油……………………………………………79
二、共軛亞麻油酸甲酯與模式油於加熱與光照過程中
的氧化安定性………………………………………………88
1. 加熱處理……………………………………………………89
2. 光照處理……………………………………………………105
三、共軛亞麻油酸甲酯之抗氧化能力…………………………111
1. 加熱處理……………………………………………………111
2. 光照處理……………………………………………………129
第五章 結論………………………………………………………135
參考文獻……………………………………………………………137

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