Jalil, Abbe Maleyki Mhd (2016) Development of functional bread with beta glucan and black tea and effects on appetite regulation, glucose and insulin responses in healthy volunteers. PhD thesis. http://theses.gla.ac.uk/7956/ Copyright and moral rights for this work are retained by the author A copy can be downloaded for personal non-commercial research or study, without prior permission or charge This work cannot be reproduced or quoted extensively from without first obtaining permission in writing from the author The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given Glasgow Theses Service http://theses.gla.ac.uk/ [email protected] Development of Functional Bread with Beta Glucan and Black Tea and Effects on Appetite Regulation, Glucose and Insulin Responses in Healthy Volunteers Abbe Maleyki Mhd Jalil BSc, MSc A thesis submitted for the degree of Doctor of Philosophy To The College of Medicine, Veterinary and Life Sciences, University of Glasgow July 2016 From research conducted at the School of Medicine, Human Nutrition University of Glasgow Glasgow Royal Infirmary, 10-16 Alexandra Parade, G31 2ER Glasgow, Scotland © A.M.M Jalil 2016 Author's declaration I declare that the original work presented in this thesis is the work of the author Abbe Maleyki Mhd Jalil. I have been responsible for the organisation, recruitment, sample collection, laboratory work, statistical analysis and data processing of the whole research, unless otherwise stated. Abbe Maleyki Mhd Jalil ii Acknowledgements First of all I would like to thank my supervisors for their continual guidance and support throughout this study. For Dr. Ada Garcia, I would like to thank her for the time, support, instruction, and technical knowledge that she provided to me. For Dr Emilie Combet and Professor Christine Edwards, I would like to express my sincere gratitude for their knowledge, expertise, encouragement, support, and overall kindness. Without my supervisors I could not have done it, thank you for being so thoughtful. A big thank you to my good friend, Nuraiza Meutia for her help on cannulation. I would also like to thank you my desk mates (Majid and Sulaiman) for their thoughts, foods, advice and kind help. I would also like to give a special thanks to Dr. Dalia Malkova and Hani Alfehaaid, who helped me with the lab analysis of appetite hormones. I would like to acknowledge the lab technicians, Frances Cousins, Graeme Fyffe, John McMillan and Susan Ridha for helping me with ordering and organizing our lab. Not to forget Michael Logan, Mhairi McGowan, Hannah Harris, Jaafar Khan, Clare Clark, Eleni Rizou, Susanna Palma, Maira Bouga, Min Hou, Vaios Svolos and Jaroslav for their thoughts, laugh and good foods. I would like to thank you to Ministry of Education (Malaysia) and Universiti Sultan Zainal Abidin (UniSZA) for their sponsorship and support. iii Dedication I would like to dedicate my thesis to my parents (Hasnah, Norehan, Mhd Jalil and Mohd Nasser), my wife (Nadia Nazeerah Nasser) and my three little boys (Anas, Aqeel and Ammar). I was very lucky that they were able to be close to me and encourage my every step. I will be eternally grateful for their support, love and prayers. iv Table of Contents AUTHOR'S DECLARATION II ACKNOWLEDGEMENTS III DEDICATION IV TABLE OF CONTENTS V LIST OF TABLES VIII LIST OF FIGURES IX ABBREVIATIONS XIII ABSTRACT 1 1 CHAPTER 1: INTRODUCTION 3 1.1 Food matrix interactions of dietary fibre, (poly)phenols and macronutrients 6 1.1.1 (Poly)phenols-dietary fibre interaction 6 1.1.2 Interaction of (poly)phenols, dietary fibre and macronutrients 8 1.2 Functional foods 11 1.3 β-Glucan in functional foods 13 1.4 Physiological effects of soluble viscous fibres in the upper gut 21 1.4.1 Effects of viscous fibres on gastric emptying 25 1.4.2 Effects of viscous soluble fibres on digestion and absorption 27 1.4.3 Postprandial glucose and insulin 29 1.5 Physiological roles of β-Glucan in lower gastrointestinal tract 35 1.5.1 Colonic fermentation 35 1.5.2 Colonic fementation products 37 1.6 Stimulation of gastrointestinal hormones 44 1.6.1 CCK 46 1.6.2 Peptide YY (PYY) 48 1.6.3 GLP-1 52 1.7 Dietary (poly)phenols 54 1.7.1 Basic (poly)phenol structures 55 1.7.2 Tea (poly)phenols 58 1.7.3 Tea in food products 62 1.8 Physiological effects of tea (poly)phenols 63 1.8.1 Tea (poly)phenols metabolism and absorption 64 1.8.2 Colonic fermentation of tea (poly)phenols 68 1.8.3 Effects of tea intake on postprandial glucose and insulin levels 70 1.9 Effects of drinking tea on perceived satiety 74 1.10 Hypothesis to be tested in this thesis 79 2 CHAPTER 2: GENERAL MATERIALS AND METHODS 80 2.1 Study one: Bread development, starch functionality, antioxidant activity and short- chain fatty acid production from in vitro fermentation 82 2.1.1 Bread development 82 2.1.2 Materials for bread making 82 2.1.3 Bread preparation 82 2.2 Proximate analysis 84 2.2.1 Protein content (Kjedahl method) 84 2.2.2 Fat content (solvent extraction, Soxlet method) 84 2.2.3 Resistant starch (RS) and solubilised (digestible) starch 85 2.2.4 β-Glucan content 88 2.2.5 Starch hydrolysis of breads 89 2.2.6 Microscopic study of breads structures 90 2.2.7 In vitro digestion model 90 2.2.8 Determination of total (poly)phenols 93 2.2.9 Determination of ferric reducing ability of plasma (FRAP) assay 93 2.2.10 In vitro batch fermentation 94 2.3 Study two: Effects of functional breads on palatability and satiety 99 2.3.1 Breakfast meal preparation 99 2.3.2 Ad libitum lunch and energy intake estimation 101 2.3.3 Satiety and palatability scoring (adaptive visual analogue scale, AVAS) 101 2.4 Study three: Effects of functional breads on postprandial glucose, insulin and gut hormones 103 2.4.1 Blood collection 103 2.4.2 Total cholecystokinin (CCK) determination 105 2.4.3 Active glucagon-like peptide (GLP-1) determination 107 2.4.4 Total peptide YY (PYY) determination 108 3 CHAPTER 3: COMBINED EFFECTS OF ΒETA GLUCAN AND BLACK TEA ON STARCH HYDROLYSIS, ANTIOXIDANT POTENTIALS AND IN VITRO BATCH FERMENTATION 110 3.1 Introduction 112 3.2 Materials and methods 115 3.2.1 Materials and bread preparation 116 3.2.2 Proximate analysis 116 3.2.3 Determination of resistant starch (RS) and digestible (solubilised) starch 116 3.2.4 β-Glucan content 117 3.2.5 Starch hydrolysis of bread 117 3.2.6 Microscopic study of breads structures 117 3.2.7 In vitro digestion model 117 3.2.8 Determination of total (poly)phenols 118 3.2.9 Determination of ferric reducing ability of plasma (FRAP) assay 118 3.2.10 In vitro batch fermentation 119 3.3 Statistical analysis 119 3.4 Results 120 3.4.1 Bread characteristics 120 3.4.2 Nutrient composition 120 3.4.3 Microscopic study of bread structure 123 3.4.4 Starch hydrolysis of breads 123 3.4.5 Total (poly)phenols released and antioxidant activity of breads 127 3.4.6 Short chain fatty acid production 130 3.5 Discussion 136 3.6 Conclusions 140 4 CHAPTER 4: PALATABILITY, PERCEIVED SATIETY AND AD LIBITUM ENERGY INTAKES AT LUNCH AFTER INTAKE OF FUNCTIONAL BREAD PREPARED WITH ΒETA GLUCAN AND BLACK TEA 141 4.1 Introduction 143 4.2 Experimental design 145 4.2.1 Study design 145 4.2.2 Sample Size 145 vi 4.2.3 Inclusion and exclusion criteria 146 4.2.4 Subject recruitments 146 4.2.5 Study protocol 146 4.3 Materials and methods 147 4.3.1 Breakfast meal preparation 147 4.3.2 Ad libitum lunch and energy intake estimation 147 4.3.3 Satiety and palatability scoring (adaptive visual analogue scale, AVAS) 148 4.4 Statistical analysis 148 4.5 Results 151 4.6 Discussion 163 4.7 Conclusions 168 5 CHAPTER 5: EFFECTS OF FUNCTIONAL BREADS PREPARED WITH ΒETA GLUCAN AND BLACK TEA ON POSTPRANDIAL GLUCOSE, INSULIN AND APPETITE HORMONES IN HEALTHY VOLUNTEERS 169 5.1 Introduction 171 5.2 Experimental design 172 5.2.1 Study design 172 5.2.2 Sample size 172 5.2.3 Inclusion and exclusion criteria 173 5.2.4 Subject recruitment 173 5.2.5 Study protocol 173 5.2.6 Statistical analysis 177 5.3 Results 178 5.4 Discussion 191 CHAPTER 6: GENERAL DISCUSSION 198 6.1 Summary of results 200 6.2 Relationship between in vitro and in vivo studies, and possible explanations 206 6.3 Reflections on methodology: strengths and limitations 208 6.4 Implications for food industry 212 6.5 Implications for healthy eating at the population level 213 6.6 Future research 214 6.7 Conclusions 215 7 REFERENCES 218 vii List of Tables Table 1-1. Current dietary fibre definitions from around the world. Adapted from (Jones, 2014) ........................................................................................................................... 15 Table 1-2. Different types and characteristics of soluble dietary fibres .............................. 18 Table 1-3. Different types and characteristics of β-glucan ................................................. 20 Table 1-4. Association between total dietary fibre (or whole grain) intakes and chronic diseases (T2DM, cancers and CVDs). ........................................................................ 23 Table 1-5. Effect of β-glucan containing foods on postprandial glycaemia and insulin levels in healthy subjects.