臺灣博碩士論文加值系統

中文摘要
學號 : N9236010
論文名稱 :不同加工製程及不同採收季節對阿里山烏龍茶抗氧化活性之探討
總頁數 : 103
學校名稱 : 國立屏東科技大學 系(所)別 : 食品科學系碩士班
畢業時間及摘要別 : 九十八學年度第二學期碩士學位論文摘要
研究生 : 梁孟鈞 指導教授 : 謝寶全、蔡碧仁 博士
論文摘要內容 :

茶葉因含有豐富的茶多酚，而具有良好的抗氧化性質，經研究更證實多酚化合物比維生素C、E和β-胡蘿蔔素更具有抗氧化性。茶葉製造時發酵程度之不同會影響酚類化合物之含量，一般而言，茶葉中酚類化合物含量，隨發酵程度之加深而漸減，同時也衍生烏龍茶特殊之香氣與滋味。但製程和季節對茶葉中酚類化合物及抗氧化力之影響卻缺乏資料，故本研究採用不同採收季節及不同加工階段之阿里山烏龍茶葉為原料，比較其總酚、類黃酮及總兒茶素之抗氧化活性差異。由實驗結果顯示，阿里山烏龍茶以水為溶劑，在50 ℃下萃取30分鐘有最佳DPPH自由基清除能力及還原力，且隨著濃度的增加而提高。進一步探討其加工製程不同階段之茶葉，如:新鮮茶葉(茶菁)、冷凍茶(揉捻後之茶葉)、初製茶及精製茶之抗氧化活性評估及抗氧化成份。結果顯示，茶菁的抗氧化成份及抗氧化活性皆最低。在不同採收季節方面，FRAP還原力以春、秋茶高於夏、冬茶，但DPPH清除能力則以春、冬茶優於夏、秋茶。為更精確評估茶葉抗氧化活性，將各樣品以紅外線水份測定儀測定其水分含量，結果顯示，茶菁之水分含量最高(76.5%)，而精製茶水分含量最低(5.9%)，之後以乾重計算類黃酮、總酚、總兒茶素及各別兒茶素之含量。類黃酮含量以夏、秋茶含量高於冬茶及春茶，總酚含量則以夏、冬茶高於春、秋茶。以HPLC分析各樣品中沒食子酸(GA)、表沒食子兒茶酸(EGC)、表沒食子兒茶酸鹽(EGCG)和咖啡因(CAF)之含量，發現茶菁中之酚類以GA、EGC、EGCG及CAF含量最高，而精製茶含量最低。由此得知茶葉的發酵導致兒茶素濃度減少，尤其以EGC及EGCG之含量影響最大。茶葉依加工條件不同，其酚類化合物衍生物也不同。在發酵過程中，兒茶素和茶黃質結合成複雜的酚類化合物，提供獨特的風味和顏色，且帶動烏龍茶之抗氧化活性變化。
關鍵字：烏龍茶、總酚、類黃酮、抗氧化活性

Abstract
Student ID : N9236010

Title of thesis : Studies on antioxidative activity of Alishan oolong tea from different seasons and process.

Total page : 103

Name of institute : National Pingtung University of Science ＆ Technology Department of Food Science
Graduate date : 2010.7 Degree Conferred : Master

Name of student : Meng-Jun Liang Adviser : Pao-Chuan Hsieh
Pi-Jen Tsai
The contents of abstract in this thesis :

Tea is rich in polyphenols due, and has good antioxidant properties. The study confirmed that polyphenols had more antioxidant activity than vitamin C, E and β-carotene. The content of phenolic compound in tea depends on the degree of fermentation. Generally speaking, phenolic compound will decrease during fermented processing. However, the effects of season and process on the phenolic compounds of tea lack of information. In this study, the tea leaves of Alishan oolong tea from difference harvest seasons and processing steps were used as raw materials to compare their difference in total phenol, flavonoid, total catechin and antioxidant activity. The results indicated that DPPH free radical scavenging and FRAP reducing power were the highest in the sample extracted by water at 50℃ for 30min and increased with the increasing concentration. Further more, we compared of the tea from different possessing step (fresh tea (tea leaves), cold tea (tea after twisting), preliminary tea and refined tea). It revealed that the fresh tea exhihibited the lowest amount of antioxidant and antioxidant activity . For the harvesting seasons, the FRAP reducing power of spring, and autumn teas were higher than that of summer and winter teas, but the DPPH scavenging ability of spring and winter teas were higher than that of summer and autumn teas. The moisture contents of the teas were measured. The results showed that the moisture content of tea leaves were the highest (76.5%), while the refined tea was the lowest (5.9%). Flavonoids contents of summer tea and autumn tea were higher than that of spring tea and winter teas. Finally, gallic acid (GA), epigallocatechin (EGC), epigallocatechin gallate (EGCG), and caffeine (CAF) of teas were analyzed by HPLC. GA, EGCG, EGC and CAF contents were the highest in fresh tea leaves, it appears that the result of fermentation of tea catechin concentrations, particularly in the EGC and EGCG contents were the hishest, while content of refined tea was the lowest. According to this study, catechins and theaflavins of tea form a complex phenolic compounds providing a unique flavor and color,in the fermentation process.The phenolic compounds derivatives and their antioxidative activities of tea were different, depending on the harvest seasons and processing conditions.

Key words : oolong tea, polyphenols, flavonoids, antioxidative activity

目錄
第一章、前言…………………………………………………………………1
第二章、文獻回顧……………………………………………………………3
一、引言……………………………………………………………3
二、茶的歷史………………………………………………………5
三、臺灣茶葉之起源及品種………………………………………6
四、茶葉之分類……………………………………………………7
五、茶葉之發酵與萎凋……………………………………………11
六、茶葉的製程及原理……………………………………………13
七、多元酚類生合成及氧化過程…………………………………18
八、製茶過程中影響多元酚類之因子……………………………20
九、茶葉精製與焙火………………………………………………20
十、茶葉包裝與儲存………………………………………………23
十一、茶葉之成分及其功效………………………………………23
十二、茶葉抗氧化成分……………………………………………27
十三、兒茶素在生理抗氧化上之作用……………………………29
第三章、實驗材料與方法……………………………………………………31
一、實驗架構………………………………………………………31
二、實驗材料………………………………………………………32
(一)茶葉………………………………………………………32
(二)阿里山烏龍茶不同加工製程之茶葉……………………32
(三)不同採收季節之阿里山烏龍茶…………………………34
(四)藥品………………………………………………………35
1.標準品…………………………………………………35
2.試藥……………………………………………………35
3.溶劑……………………………………………………36
4.儀器設備………………………………………………36
三、實驗方法…………………………………………………………37
(一)樣品之製備…………………………………………………37
1.一般製備…………………………………………………37
2.樣品製備…………………………………………………37
(二)初步抗氧化力比較……………………………………………38
1.各種茶種之抗氧化力比較…………………………………38
2.各種茶種之初步pH值測……………………………………38
(三)烏龍茶清除DPPH自由基能力及還原力之初步萃取條件的探
討………………………………………………………………38
(四)不同加工製程及不同季節對烏龍茶抗氧化物質的影響……39
(五)以HPLC分析茶中萃取物之抗氧化成分………………………39
(六)抗氧化活性能力測定…………………………………………39
1.DPPH自由基清除能力試驗…………………………………39
2.螯合亞鐵離子能力之測定…………………………………40
3.還原力測定…………………………………………………41
(七)抗氧化活性成分測定…………………………………………42
1.總酚含量測定………………………………………………42
2.類黃酮含量測定……………………………………………42
3.總兒茶素含量測定…………………………………………43
4.HPLC分析…………………………………………………44
(1)HPLC 分析條件………………………………………44
(2)標準品之配製…………………………………………44
5.統計分析……………………………………………………44
第四章 結果與討論………………………………………………………………45
一、各種茶種之初步抗氧化力比較及pH值測定………………………45
二、阿里山烏龍茶清除DPPH自由基能力及還原力之初步萃取條件的探
討……………………………………………………………………48
三、不同加工製程及不同採收季節對阿里山烏龍茶抗氧化活性能力測
定之探討……………………………………………………………54
(一)DPPH自由基清除能力試驗……………………………………54
(二)還原力…………………………………………………………58
(三)螯合亞鐵離子能力……………………………………………61
(四)阿里山烏龍茶之水分含量及萃取率…………………………65
(五)總酚含量………………………………………………………69
(六)類黃酮含量……………………………………………………74
(七)總兒茶素含量…………………………………………………77
四、HPLC分析烏龍茶萃取物之抗氧化成分……………………………79
(一)以HPLC分析在不同加工過程之阿里山烏龍茶萃取液………85
(二)以HPLC分析在不同採收季節之阿里山烏龍茶萃取液………89
五、咖啡因 ………………………………………91
六、相關性之分析………………………………………………………92
第五章 結論………………………………………………………………………95
第六章 參考文獻…………………………………………………………………96
第七章 作者簡介…………………………………………………………………103