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Title of Thesis

Extraction of green tea catechins for the preparation of functional drink: correlation with lifestyle-related disorders

Author(s)

Rabia Shabir Ahmad

Institute/University/Department Details
National Institute Of Food Science & Technology / University Of Agriculture, Faisalabad
Session
2010
Subject
Food Technology
Number of Pages
199
Keywords (Extracted from title, table of contents and abstract of thesis)
Functional, Extraction, Nutraceutical, Catechins, Green, Preparation, Functional, Measured, Cholesterol, Hypercholesterolemia, Disorders, Correlation, Triglycerides, Lifestyle, Effectiveness

Abstract
Present research project was an attempt to explore the functional/nutraceutical worth of locally grown green tea variety (Qi-Men)against lifestyle-related disorders. For the purpose, green tea catechins and epigallocatechin gallate (EGCG) were characterized and subsequently utilized for the preparation of functional drink and then tested in experimental rats modeling. Regarding chemical composition, green tea is rich in polyphenols with special reference to flavonoids including catechins. Among minerals, potassium and calcium were present in substantial amount whilst sodium, manganese, iron and zinc in relatively less quantity. Optimization of extraction conditions was carried out using various solvents (aqueous ethanol, aqueous methanol, water) and time intervals (20, 40, 60 min) to improve extraction efficiency of catechins. EGCG, a major fraction of green tea catechins was also separated through solvent partition method. HPLC quantification of catechin fractions revealed that maximum amount of epigallocatechin (EGC), epigallocatechin gallate (EGCG), epicatechin gallate (ECG) and epicatechin (EC) was extracted with aqueous ethanol at 40 min. In vitro analysis for antioxidant activity and DPPH radical scavenging ability of catechins and EGCG proved their excellent antioxidant potential. Based on the results of extraction efficiency, HPLC analysis and in vitro tests, one best treatment from extracted catechins was selected for the preparation of functional drink (Green Cool). In product development phase, three functional drinks were prepared i.e catechins containing drink, EGCG enriched drink and a control for comparison purpose. Drinks were subjected to physico-chemical analysis during two months storage that showed non-substantial effect on total soluble solids (TSS) whilst pH and acidity were affected significantly. Color of the drinks measured through CIELAB system, affected non-momentously. Hedonic response of the functional drinks remained acceptable during storage. Efficacy trials were carried out in male Sprague Dawley rats to explore the nutraceutical worth of drinks against ailments arising due to unhealthy lifestyle. For the purpose, four studies were performed on the basis of various diets given to rats i.e. study I (normal diet), study II (high cholesterol diet), study III (high sucrose diet), study IV (high cholesterol + high sucrose diet). Functional drinks containing catechins and EGCG resulted in significant reduction in body weight of rats indicating their effectiveness against obesity and allied discrepancies. Maximum reduction in body weight gain was in study II and III i.e. 10.73 to 8.49 % and 10.12 to 10.49% in groups consumed catechins and EGCG, respectively. Likewise, cholesterol and LDL were substantially reduced by functional drinks however, effect was more pronounced in catechins group in which 14.42% decrease was observed in study IV and 30.43% in study II,respectively. HDL was non-significantly affected by the treatments.Triglycerides were also reduced by drinks carrying bioactive molecules in rats provided diets rich in cholesterol and sucrose. Serum glucose and insulin levels were also mitigated by functional drinks containing catechins and EGCG. Similarly, antioxidant potential was improved as indicated by elevated serum glutathione level and decreased thiobarbituric acid reactive substances(TBARS) via both drinks containing catechins and EGCG but latter was more effectual for the purpose. Organs to body weight ratio remained unaffected by functional drinks.Furthermore, serum biochemistry values were within normal range revealing safety of use.From the present investigation, it is deduced that drinks supplemented with catechins and EGCG are effective against obesity, hypercholesterolemia, hyperglycemia and oxidative stress therefore, can be a part of diet based therapy for attenuation of lifestyle-related disorders.

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1,318 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 CONTENTS

 

vi
14 KB
2

1

INTRODUCTION

 

1
31 KB
3 2 REVIEW OF LITERATURE

2.1 Green tea; an overview
2.2 Extraction of catechins
2.3 In vitro studies of green tea
2.4 Functional foods and beverages
2.5 Lifestyle disorders and green tea
2.6 Health claims of epigallocatechin gallate (EGCG)

6
135 KB
4 3 MATERIALS AND METHODS

3.1 Materials
3.2 Characterization of green tea
3.3 Extraction from green tea
3.4 HPLC analysis of catechins
3.5 In vitro studies
3.6 Selection of best treatment
3.7 Functional drink
3.8 Efficacy studies
3.9 Statistical analysis

31
64 KB
5

4

RESULTS AND DISSCUSSION

4.1 Characterization of green tea
4.2 Extraction and analysis of active ingredients
4.3 In vitro studies
4.4 Product development
4.5 Efficacy studies

46
825 KB
6

5

SUMMARY

 

156
44 KB
7

6

APPENDICES

 

154
192 KB