Addis Ababa University Addis Ababa Institute of Technology School of Chemical and Bioengineering
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ADDIS ABABA UNIVERSITY ADDIS ABABA INSTITUTE OF TECHNOLOGY SCHOOL OF CHEMICAL AND BIOENGINEERING QUALITY IMPROVEMENT AND SHELF STABILTY OF BEER BY CONTROLLED MALT BLENDING RATIOS WITH RESPECT TO MALT PROTEIN CONTENT A Thesis Submitted to the School of Graduate Studies, Addis Ababa Institute of Technology, for Partial Fulfillment of the Requirement for the Degree of Master of Science in Chemical Engineering (Food Engineering) By: - Yidnekachew Hailu Advisor: - Dr. Eng Shimelis Admassu (Associate Professor) Addis Ababa, Ethiopia January, 2020 i Declaration I ,the undersigned, declare that this thesis presented for the attainment of the degree of Master of science in Chemical Engineering(Food Engineering) has been composed solely by myself and has not been presented or submitted ,in part or as whole, for a degree in any other institution or university. The Thesis presented is my original work and all sources of information or materials used for the thesis have been duly acknowledged. Mr.Yidnekachew Hailu Tadesse Signature: _____________ Date: _____________ Msc Candidate This Thesis has been submitted for examination with my approval and done under my supervision as University advisor. Dr.Eng Shimelis Admasu Emire Signature: _____________ Date: _____________ Advisor The Undersigned member of the thesi9s examining board appointed to examine the thesis of Mr.Yidnekache Hailu is submitted for the degree of Master of Science in Chemical Engineering (Food Engineering) confirmed that the thesis fulfills the requirements of the graduate program and approved it to be accepted. Approved by the examining Board Signature Date __________________________ _____________ _____________ Chairman, School’s Head Mr.AdamuZegeye _____________ _____________ Internal Examiner Dr.Helen W/Gabriel _____________ _____________ External Examiner i Acknowledgements I am so indebt to my Advisor, Dr. Engineer Shemelis Admasu , for his closest follow-up and leadership next to the Almighty GOD. I would like to offer my sincere thanks to the School of Chemical Bioengineering, Addis Ababa Institute of Technology and BGI Ethiopia Plc, Special thanks goes to the manager, Mr. Workneh Birhanu. I would like to extend my gratitude towards the following individuals too: Ato Kebena Bula, Ato Elias Hailu, Ato Yizengaw Eniyew, Ato Derejen Tilahun, Ato Belachew Assefa, Ato Wasyhun Yihunie, W/o Azeb G / Giorgis and Ato Mesfin Shumye. I would like to thank also my family members for their consistent support and inspiration namely: my mother (W/o Nunu Altaseb), my brothers Ato Abenezer Amdie and Ato Esayas Hailu. I am also greatful to my classmates for the care and teamwork. I want to give credit to staff members of Center for Food Science and Nutrition of Addis Ababa University (Dr.Paulos Getachew, Dr. Kaleab Baye, Ato Kelbessa Urga ,Ato Debebe Hailu), for their support. I also acknowledge staff members of Ethiopian Public Health Institute: Ato Biniyam Tesfaye, Ato Daniel Abera and Ato Mesay Getachew, among others. ii Table of Contents Title Page Numbers Acknowledgements ii Table of contents iii Abbreviations vi List of Tables vii List of Figures viii Abstract- ix Chapter-1 1 1. Introduction 1 1.1. Background 1 1.2. Statement of the problem 2 1.3. Significance of the study 3 1.4. General Objective 3 1.5. Specific Objectives 3 Chapter-2 4 2. Literature review 4 2.1. Introduction 4 2.2. Impact of malt protein on brewing optimization 4 2.3. Overview of beer manufacturing in Ethiopia 5 2.4. Beer Production process technology 7 2.4.1. Malted Grains 7 2.4.2. Beer Quality and Stability 12 2.4.3. The Nature of beer Particles 12 2.4.4. Origin and control of Particles in brewing process 13 2.4.4.1. Mashing 13 2.4.4.2. Wort Boiling 14 2.4.4.3. Wort Cooling 14 2.4.4.4. Fermentation 14 2.4.5. Wort and beer Clarification 15 2.5. Settlements/Sedimentation of Solids 15 iii 2.5.1. Colloidal Stability 16 2.5.2. Turbidity and Haze Formation 17 2.5.2.1. Components of Haze particles 18 2.5.2.2. Polyphenol 19 2.5.2.3. Prolamin storage protein: General properties 20 2.5.2.4. Regulation of prolamin gene expression 21 2.5.3. Proteomic Analysis of different extracts from barley grains 22 2.5.4. Particles Contributing to Turbidity in Beer 22 2.6. Accelerated Shelf- Life Testing 24 2.6.1. Predicting the Shelf-Life of Beer 24 2.6.2. Predicting Test 25 2.6.2.1. Accelerated beer aging test 25 2.6.2.2. Predicting Test 26 2.6.2.3. Sensitive protein content 26 2.6.2.4. Chilling Test 26 2.6.2.5. Polyphenol (Tannoid) content titrating with pvpp 26 Chapter-3 29 3. Material and Methods 29 3.1. Materials 29 3.1.1. Chemicals 29 3.2. Experimental Design Summary 30 3.2.1. Factors, the corresponding ranges and levels 30 3.2.2. Response Summary 30 3.2.3. Several blending ratios responses 30 3.2.4. Optimization of process for mixture D-optimal 31 3.2.4.1. Constraints applied for the Optimization 31 3.2.4.2. Selected Optimum Solution 31 3.2.4.3. Validation of Optimal Combination (Comparison of Products) 31 3.3. Malt Analysis 32 3.3.1. Total Protein Content 33 3.3.2. Moisture Content 34 iv 3.4. Wort Analysis 34 3.4.1. Extract Yield by Mashing 34 3.4.2. Total Polyphenol 36 3.4.3. Free Amino Nitrogen (FAN) 36 3.5. Design of the Experiment 37 3.5.1. Pysico-chemical and instrument Analysis of beer 37 3.5.2. Bitterness 37 3.5.3. VDK 38 3.5.4. Total Polyphenol 38 3.5.5. Determination of Calcium ion ( Ca 2+) 38 3.5.6. Determination of Foam Stability Value 39 3.5.7. Pasteurization 39 3.6. Microbial Analysis of the beer 39 3.6.1. Saccharomyces Wild yeast 39 3.6.2. Total Count 40 3.6.3. Lactic Acid Bacteria 40 3.7. Sensory Analysis 41 Chapter-4 43 4. Results and Discussion 43 4.1. Moisture Content 43 4.2. Protein Fractionation of Malt 44 4.3. Particle size distribution 45 4.4. Pysico-chemical, Instrumental and microbial Analysis results of the beer 45 4.5. Accelerated Shelf-Life /Forcing Test Results 46 4.6. Sensory Analysis 47 Chapter-5 49 5. Conclusion and Recommendations 49 References 51 Appendix A 54 Appendix B 57 Appendix C 58 v Abbreviations EBC European Brewery Convention OG Original Gravity Al(w/w) Alcohol Weight by Weight Al (v/v) Alcohol Volume by Volume Er Real Extract Ea Apparent Extract ADOF Apparent Degree of Fermentation SG Specific Gravity BU Bitterness Unit VDK Vicinal Diketones FAO Food & Agricultural Organization LAB Lactic Acid Bacteria DMS Dimethyl Sulphide AAB Acetic Acid Bacteria GMP Good Manufacturing Practice HA Haze Active PVPP Polyvinyl Poly Pryollidon FAN Free Amino Nitrogen vi List of Tables Table 1 Main Malt Producing Countries...................................................................................................8 Table 2 Import of Malt in Ton...................................................................................................................9 Table3 Blending Ratio Response..............................................................................................................31 Table 4 Validation of Optimal Combination...........................................................................................33 Table 5 Protein Fractionation....................................................................................................................46 Table 6 Particle Size Distribution..............................................................................................................48 Table 7 Chemical Analysis results of the optimized Beer.........................................................................49 Table 8 Chill Haze Measurement after Forcing Test.................................................................................50 Table 9 sensory Analysis result.............................................................................................................51 vii List of Figures Figure 1 Malt handling and cleaning Flowchart.......................................................................................11 Figure 2 Beer Production Flow Sheet....................................................................................................14 Figure 3 Concept of Protein Polyphenol interactions leading to Haze..................................................42 Figure 4 Flavonoid Phenolic and Proanthocyanidin (Condensed Tannin) Structure..............................42 Figure 5 Mode of Combination of Proteins with Polyphenols................................................................43 Figure 6 Similarities of Polyproline and Polyvinylpyrrolidine (PVPP)..................................................43 Figure 7 Flavan-3-ol Monomers found in Malt, Hops and Beer.............................................................44 Figure 8 Flavanol 3’-4’ Ortho-hydroxy Chelation of Metals.................................................................44 Figure 9 The Oxidation of Flavan-3-ols....…………………………………………………….............45 viii Abstract The beer industry has begun its wider demand of raw materials to accomplish the vast production .Ethiopia has many breweries being opened, among the raw materials that are needed ,the Malt has been praised as the soul of the beer. Both imported and local malts are used in the beer production. Besides the maximum quality and quantity imported malt contributes for beer production, it also takes much of our foreign currency. Based on the proximate analysis of both malt variants the different parameters essential for the malt types have been analyzed. Taking the critical parameters in this research which are proteins which occur as polyphenol complexes, Free Amino Nitrogen (FAN) in The extract