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VIETNAM NATIONAL UNIVERSITY-HO CHI MINH CITY UNIVERSITY OF TECHNOLOGY VO THI KIM NGAN STUDY ON THE EXTRACTION AND ISOLATION OF CAFFEINE FROM GREEN TEA Camellia sinensis (L.) FIELD : ORGANIC CHEMISTRY MASTERS THESIS HO CHI MINH CITY, July 2010 CÔNG TRÌNH ĐƯỢC HOÀN THÀNH TẠI TRƯỜNG ĐẠI HỌC BÁCH KHOA ĐẠI HỌC QUỐC GIA TP HỒ CHÍ MINH Cán bộ hướng dẫn khoa học: TS. PHẠM THÀNH QUÂN Cán bộ chấm nhận xét 1: TS. PHẠM S Cán bộ chấm nhận xét 2: TS. NGUYỄN THỊ LAN PHI Luận văn thạc sĩ được bảo vệ tại Trường Đại học Bách Khoa, ĐHQG Tp. HCM ngày 07 tháng 08 năm 2010 Thành phần Hội đồng đánh giá luận văn thạc sĩ gồm: 1. PGS.TS Trần Thi Việt Hoa 2. TS. Phạm Thành Quân 3. TS. Trần Thị Kiều Anh 4. TS. Phạm S 5. TS. Trần Lê Quan Xác nhận của Chủ tịch Hội đồng đánh giá LV và Bộ môn quản lý chuyên ngành sau khi luận văn đã được sửa chữa (nếu có). Chủ tịch Hội đồng đánh giá LV Bộ môn quản lý chuyên ngành TRƯỜNG ĐẠI HỌC BÁCH KHOA TP. HCM CỘNG HÒA XÃ HỘI CHỦ NGHĨA VIỆT NAM PHÒNG ĐÀO TẠO SAU ĐẠI HỌC Độc Lập - Tự Do - Hạnh Phúc Tp.HCM, ngày 0 5 tháng 0 7 năm 2010 NHIỆM VỤ LUẬN VĂN THẠC SĨ Họ và tên học viên : VÕ THỊ KIM NGÂN Phái: Nữ Ngày tháng năm sinh: 06/04/1982 Nơi sinh : Tiền Giang Chuyên ngành : CÔNG NGHỆ HỮU CƠ MSHV : 00507378 I.TÊN ĐỀ TÀI Nghiên cứu trích ly và tách caffeine từ trà xanh II. NHIỆM VỤ VÀ NỘI DUNG Khảo sát ảnh hưởng của các yếu tố nhiệt độ, thời gian, tỷ lệ rắn- lỏng và số lần trích đến lượng caffeine trong dịch trích từ trà bằng nước . Khảo sát sự hấp phụ caffeine khi cho dịch trích chảy qua cột hấp phụ với bốn loại chất hấp phụ khác nhau: XAD-4, XAD-7, IR 120H và than hoạt tính . Khảo sát sự giải hấp caffeine từ các cột hấp phụ nói trên với các dung môi giải hấp khác nhau: ethanol, acetone, ethyl acetate, chloroform và hexane . III. NGÀY GIAO NHIỆM VỤ: 01/2010 IV. NGÀY HOÀN THÀNH NHIỆM VỤ: 06/2010 V. CÁN BỘ HƯỚNG DẪN: TS. PHẠM THÀNH QUÂN CÁN BỘ HƯỚNG DẪN CN BỘ MÔN QL CHUYÊN NGÀNH ACKNOWLEDGEMENTS I would like to acknowledge the following people for their contributions to the project: My supervisor, Dr. PHAM THANH QUAN for his time, guidance and enthusiasm throughout the project. Professors and staffs of the Department of Organic Chemistry and Faculty of Chemical Engineering for their help and useful advice. My friends in the Laboratory of Organic Chemistry for their help. My family for their support and encouragement. i ABSTRACT Caffeine is the world’s most popular drug and consumed everyday by millions of people in the world. It is also used in many beverages and food. Due to its ability to relieve headache and stimulate breathing, caffeine has been used in headache relieving medicine, treatment of cessation of breathing for newborn babies and as an antidote against the depression of breathing by overdoses of heroin. Caffeine was found in tea with a content of 3-4 %. Tea has been widely grown in Vietnam and is a large potential source of caffeine production. In this project, the extraction and isolation of caffeine from Vietnamese green tea were intensively studied and several results were obtained as below. • Green tea was extracted by hot distilled water and the optimal caffeine extraction was established for 5g of tea: 10 min, 75oC, solid-liquid ratio of 1/20, one-time extraction. The caffeine amount in the tea extract is 3.2 times that of EGCG. • Caffeine in the tea extracts were adsorbed onto four adsorbent columns (XAD-4, XAD-7, IR-120H, activated carbon) by passing the extracts through the columns. XAD-4 was found to have the highest adsorption affinity for caffeine while IR-120H has the highest adsorption ability for EGCG. • Caffeine was desorbed from the columns by different solvents: ethanol, acetone, ethyl acetate, chloroform and hexane. Acetone showed the best desorption capability for caffeine compared to other solvents. EGCG was not found in the desorption solutions from XAD-4, XAD-7, activated carbon but was detected in the desorption solutions by ethanol, acetone and ethyl acetate from IR-120H column. ii TABLE OF CONTENTS ! ""# $% &'(&%)&* * &'(&%+, -(&. )&/#&0 1'* 2 )&* 2 )&&3 !3&'+, 2 )&45&+ %&0"%, *%&()&%&()& !%&0)&6 *%&()&6 *%&4%7 **81 **'(0(()&, *-((.%9 *1% ()&&32 )&(.: )&(& .9 -!2 )&3&'+0"%45(.#*- -&'(%&4#;'/&3&')&&3 !'&. *- -&'(%&4#;'/&3&')&&3'&. *, -*! &32 )&)'&2 !'&.<%&0=0>.=7? 17&@*6 iii --! &3'(.&2 !'&.<%&0=0>.=7?7 '@- -1! &3%&0;0>.<;#@)&&2 !'&.<91&A 7'@- -,! &3.'4&32 )&)'%&2 !'&.<91&A 7'A=7@ -*!%&0)&45 &0.'%&()&%&()&-9 -*8;- &0.'-9 -*%&()&B5&3!%&4%3& !1* -**8;9 &0.'1- -*- )" 4& &0.'1, -*1;7 &0.'16 C, ,1 40%&3,1 0 .0)&3&'.0%6* *5( 0;%( 61 iv LIST OF TABLES v LIST OF FIGURES vi [...]... It is more common than any medicine The average daily caffeine intake in the United States is about 200 mg per individual [12] Caffeine is widely used in beverage industry Soft drinks typically contain about 10 to 50 milligrams of caffeine per serving By contrast, energy drinks such as Red Bull can start at 80 milligrams of caffeine per serving The caffeine in these drinks either originates from the... used to analyze the amounts of tea caffeine and polyphenols To determine caffeine amount, lead acetate was used to remove polyphenols out of the extract The extraction of tea polyphenols and tea caffeine with MAE for 4 min (30 and 4%) were higher than those of extraction at room temperature for 20 h, ultrasonic extraction for 90 min and heat reflux extraction for 45 min (28 and 3.6%), respectively From... the effectiveness of such products has not been proven, and they are likely to have little stimulatory effect on the central nervous system because caffeine is not readily absorbed through the skin Table 2 2 Caffeine in some commercial products Serving size Product Caffeine per serving (mg) Caffeine tablet (regular-strength) Caffeine tablet (extra-strength) 1 tablet 1 tablet 100 200 Excedrin tablet... in the world Caffeine was discovered in green tea in the 1820s Caffeine content in green tea leaves was found to be 3-4 %, which is higher than that in coffee bean (1.1-2.2%) Tea plants have been intensively grown in many areas in Vietnam, such as Thai Nguyen, Tuyen Quang, Lam Dong This is a large potential supply of caffeine However, up-todate, most of this green tea source has been only used for exportation... soft candy [4] Caffeine is a substance that can stimulate the central nervous system It makes people more alert, less drowsy and improves coordination Combined with certain pain relievers or medicines for treating migraine headache, caffeine makes those drugs work more quickly and effectively Caffeine alone can also help to relieve headaches Antihistamines are sometimes combined with caffeine to weaken... of caffeine with small amounts of theobromine and theophylline Chocolate derived from cocoa beans contains a small amount of caffeine The weak stimulant effect of chocolate may be due to a combination of theobromine and theophylline as well as caffeine A typical 28-gram serving of a milk chocolate bar has about as much caffeine as a cup of decaffeinated coffee, although some dark chocolate currently... since, for a given extraction method, capital costs are relatively constant 2.2.2 Extraction of caffeine from green tea Due to the important role of caffeine in food, beverage and pharmaceutical industries, there have been several attempts to isolate caffeine from tea by extraction 2.2.2.1 Extraction by organic solvents Extraction of caffeine from tea is an important industrial process and can be... extraction yield was 54% while the EGCG extraction yield was 21%, resulting in caffeine/ EGCG extraction selectivity of 2.57 2.2.2.3 Microwave-assisted extraction of tea polyphenols and tea caffeine from green tea leaves A microwave-assisted extraction (MAE) method was used for the extraction of tea polyphenols (TP) and tea caffeine from green tea leaves Various experimental conditions, such as ethanol... caffeine- like substances: theophylline, which is a stronger stimulant than caffeine, and theobromine, which is slightly weaker than caffeine The most important sources of caffeine are coffee (Coffea spp.), tea (Camellia sinensis), guarana (Paullinia cupana), maté (Ilex paraguariensis), cola nuts (Cola vera), and cocoa (Theobroma cacao) The amount of caffeine found in these products varies – the highest amounts... and activated carbons, macroporous polymeric adsorbents are more attractive alternatives because of their wide range of pore structures and physic-chemical characteristics Because of its high chemically stability and excellent selectivity towards aromatic solutes, Amberlite XAD-4 polymeric resin, a macroporous styrene-divinylbenzene copolymer, is found to be a good polymeric adsorbent for organic compounds . ly và tách caffeine từ trà xanh II. NHIỆM VỤ VÀ NỘI DUNG Khảo sát ảnh hưởng của các yếu tố nhiệt độ, thời gian, tỷ lệ rắn- lỏng và số lần trích đến lượng caffeine trong dịch trích từ trà bằng nước . Khảo. xét 2: TS. NGUYỄN THỊ LAN PHI Luận văn thạc sĩ được bảo vệ tại Trường Đại học Bách Khoa, ĐHQG Tp. HCM ngày 07 tháng 08 năm 2010 Thành phần Hội đồng đánh giá luận văn thạc sĩ gồm: 1. PGS.TS Trần. contains two caffeine-like substances: theophylline, which is a stronger stimulant than caffeine, and theobromine, which is slightly weaker than caffeine. The most important sources of caffeine
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