Comparative Studies On The Wort Properties Of A Nigerian Grown Sorghum Malted In The Industry And In The Laboratory

ALOH | 102 pages (25216 words) | Theses
Microbiology | Co Authors: CLETUS UCHECHUKWU

 

ABSTRACT

There is limited information on the quality of sorghum malt produced commercially at the high temperature of 30oC. This study investigated and compared wort properties of a Nigerian grown sorghum malted in the industry and malted in the laboratory. Total of 6 kg of sorghum sample used in this study was supplied by the Nigerian Breweries PLC., Aba plant. The methods of analysis of the Institute of Brewing (IOB), 1997 and Laboratory Methods in malting of International Centre for Brewing and Distilling (ICBD) were used to analyze all the parameters of the specific objectives. Variable results with similar patterns were observed on germinated sorghum malt from Nigerian Breweries Plc. Laboratory, and ranged as follows: moisture content (6.02 – 7.83%), diastatic power (23.76 - 43.32oWK), and α-amylase (38.98 - 43.88 DU) and β-amylase (29.2–34.77oL) whereas from Herriot-Watt University Laboratory, the moisture content (6.26 – 7.88%), diastatic power (23.83 - 43.72oWK), and α-amylase (40.1 – 44.0 DU) and β-amylase (30.4 – 35.1oL) were recorded. High values of α and β-amylases were enhanced at the higher temperature of 30°C except moisture content which was at 26 °C. Highest results observed by comparing laboratory made sorghum malt to commercial made sorghum malt included HWE (294 and 288 Lo/Kg) at 28oC on day 5, FAN (162 and 142 mg/L) at 28oC on day 5 and TSN (0.62 and 0.62 %) at 30oC on day 6, showed that optimum malting days is best at 5days at 280C. In analyzes for HWE and FAN, laboratory malted sorghum using a non-conventional mashing method-decantation mashing showed higher values with stronger correlation more than conventional mashing method-infusion mashing method when compared to industrially produced sorghum malt except for TSN values. These results have shown that sorghum malt can yield enough extract when compared to barley by applying this non-conventional decantation mashing method.

 

 

TABLE OF CONTENTS

                                                                                                                                   

Title Page                                                                                                                    i

Certification                                                                                                                ii

Dedication                                                                                                                  iii

Declaration                                                                                                                  iv

Acknowledgements                                                                                                    v

Table of Contents                                                                                                       vii

List of Tables                                                                                                              xi

List of Figure                                                                                                              xii

Abstract                                                                                                                      xiii

 

1.0       CHAPTER 1: INTRODUCTION                                                      1

1.1       Background of Study                                                                                     1

1.2       Problem Statement                                                                                          3

1.3       Justification of This Research                                                                         4

1.4       Aims and Objectives                                                                                       5

 

2.0       CHAPTER 2: LITERATURE REVIEW                                                       6

2.1       Sorghum: Classification and Distribution                                                       6

2.2       Structure of Sorghum Grain                                                                           7
2.3      
Historical Use of Sorghum in Beer Production                                              9
2.4       Malting and Brewing Processes                                                                      11

2.4.1    Malt and malting                                                                                             11
2.5       Sorghum Malting Process                                                                              12
2.5.1    Steeping                                                                                                          14
2.5.2    Germination                                                                                                    17
2.5.3    Kilning                                                                                                            20
2.5.4    Milling                                                                                                             21

2.5.5    Mashing                                                                                                          26
2.6       Enzymes in Malted Sorghum                                                                          29
2.7       Use of Sorghum Malt in Modern Beer Brewing                                            33
2.7.1    Generation of enzyme by sorghum malts                                                       33
2.7.2    Extract yields                                                                                                  34
2.7.3    Fermentable sugars                                                                                         35
2.7.4    Physiological differences of sorghum and barley in relation to malting         36

2.7.5    Protein content, grain hydration                                                                     36

2.7.6   Malting response                                                                                             38

2.7.7    Location of enzymes                                                                                       38

2.7.8    Enzyme development and soluble carbohydrate and protein-extract

            recovery in sorghum malt                                                                                39

 

3.0       CHAPTER 3: MATERIALS AND METHODS                               41

3.1       Grain/Malt Samples                                                                                        41

3.2       Study Site                                                                                                       41

3.3       Analysis of the Malt Grain                                                                             41

3.3.1    Cleaning and sorting of grains for malting                                                     42

3.3.2    Determination of mold contamination and weevil infestation                       42

3.3.3    Determination of moisture content of the grains                                            42

3.3.4    Germinative energy                                                                                         43

3.3.5    Germinative capacity                                                                                      44

3.4       Malting of the grains                                                                                       44

3.4.1    Laboratory malting of sorghum                                                                      45

3.4.1.1 Steeping                                                                                                          45

3.4.1.2 Germination of the grain samples                                                                   45

3.4.1.3 Kilning/drying of germinated grains                                                               45

3.5.      Analysis of Malt Samples                                                                               46

3.5.1    Amylase enzyme extraction assay                                                                  46

3.5.2    Diastatic power of sorghum malt                                                                    48

3.5.3    Moisture content of sorghum malt                                                                  49

3.6.      Mashing of the Sorghum Samples                                                                  49

3.6.1    Decantation mashing                                                                                      49

3.6.2    Infusion mashing                                                                                            50

3.7       Extract Determination                                                                                    51

3.7.1    Determination of hot water extract (HWE) of sorghum malt                        51

3.7.1.1 Determination of specific gravity                                                                   51

3.7.1.2 Anton parr density meter                                                                                52

3.7.2    Determination of total soluble nitrogen (TSN)                                               53

3.7.3    Determination of free alpha amino nitrogen (FAN)                                       54

3.8       Statistical Analysis                                                                                          55

 

 

4.0       CHAPTER 4: RESULTS AND DISCUSSION                                            56

4.1       Analysis of Raw Sorghum Grains Studied                                                     56


4.2       Enzyme Assay, Moisture Content and Diastatic Power Analyses on Malted
            Sorghum Grain
.                                                                                               59

4.2.1    Analysis of malted sorghum grain in Nigerian Breweries Plc. laboratory      59

4.2.2    Analysis of malted sorghum grain in Herriot-Watt University

laboratory                                                                                                        61

4.3       Extract Determination                                                                                    63

4.3.1    Germination at 26oC – hot water extract (HWE)                                           64

4.3.2    Germination at 28oC – hot water extract (HWE)                                           65

4.3.3    Germination at 30oC – hot water extract (HWE)                                           67

4.3.4    Relationship between HWE obtained from laboratory and industry malted
             sorghum                                                                                                         69

4.4       Total Soluble Nitrogen (TSN)                                                                         72

4.4.1   Germination at 26oC – total soluble nitrogen (TSN)                                       72

4.4.2   Germination at 28oC and 30oC– total soluble nitrogen (TSN)            74

4.4.3    Relationship between TSN obtained from laboratory and industry malted

sorghum                                                                                                          76

4.5       Free Amino Nitrogen (FAN)                                                                          79

4.5.1    Germination at 26oC – free amino nitrogen (FAN)                                        79

4.5.2    Germination at 28oC and 30oC– free amino nitrogen (FAN)                         81

4.5.3    Relationship between TSN obtained from laboratory and industry malted   sorghum                                                                                                          84

4.6       Discussion                                                                                                       87

 

5.0      CHAPTER 5: CONCLUSION AND CONTRIBUTION TO

            KNOWLEDGE                                                                                              95         

5.1       Conclusion                                                                                                      95

5.2.      Suggestions for further research and contribution to knowledge                   96              References                                                                                                                      

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LIST OF TABLES

4.1       Results of analysis of raw sorghum grains studied                                         57

4.2       Results of analysis of sorghum malt – Nigerian Breweries Plc. Laboratory   60

4.3       Results of analysis of sorghum malt – Herriot-Watt University Laboratory  62

4.4       Hot water extract (Lo/Kg) of laboratory made sorghum malt (germination   temperature of 26oC) compared to commercial made sorghum malt            65

4.5        Hot water extract (Lo/Kg) of laboratory made sorghum malt (germination temperature of 28oC) compared to commercial made sorghum malt            66

4.6       Hot water extract (Lo/Kg) of laboratory made sorghum malt (germination   temperature of 30oC) compared to commercial made sorghum malt            68

4.7       Total soluble nitrogen (%) of laboratory made sorghum malt (germination temperature 26oC) compared to commercial made sorghum                         73

4.8       Total soluble nitrogen (%) of laboratory made sorghum malt (germination temperature 28oC) compared to commercial made sorghum malt                 75

4.9       Total soluble nitrogen (%) of laboratory made sorghum malt (germination   temperature 30oC) compared to commercial made sorghum malt                        76

4.10     Free Amino Nitrogen (%) of laboratory made sorghum malt (germination    temperature 26oC) compared to commercial made sorghum malt             80

4.11     Free Amino Nitrogen (%) of laboratory made sorghum malt (germination    temperature  28oC) compared to commercial made sorghum malt                        82

4.12     Free Amino Nitrogen (%) of laboratory made sorghum malt (germination    temperature  30oC) compared to commercial made sorghum malt                        83

 

 

 

 

 

 

 

 

 

LIST OF FIGURES

2.1       Diagram of a sorghum kernel.                                                             9

2.2       Schematic diagram of wort production                                                          13

2.3       Brewing process of western beers – Procédé de brassage des

            bièresoccidentales                                                                                           17

2.4       Diagram of unmalted and malted grain sorghum – this study                       32

4.5       Germination test for sorghum used in this study                                            58

4.6       Correlation between HWE of wort made from laboratory sorghum malt

            made at 26oC, 28oC and 30oC – decantation Vs infusion mashing                70

4.7       Correlation between HWE of wort made from industrial sorghum malt

            made at 26oC, 28oC and 30oC – decantation Vs infusion mashing                74

4.8       Correlation between TSN of wort made from laboratory sorghum malt

            made at 26oC, 28oC and 30oC – decantation Vs infusion mashing                77

4.9     Correlation between TSN of wort made from industrial sorghum malt made
           at 26oC, 28oC and 30oC – decantation Vs infusion mashing                          
82

4.10     Correlation between FAN of wort made from laboratory sorghum malt

            made at 26oC, 28oC and 30oC – decantation Vs infusion mashing                85

4.11     Correlation between FAN of wort made from industrial sorghum malt

            made at 26oC, 28oC and 30oC – decantation Vs infusion mashing                86

 

 

 

 

 

 

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APA

ALOH, A (2023). Comparative Studies On The Wort Properties Of A Nigerian Grown Sorghum Malted In The Industry And In The Laboratory. Repository.mouau.edu.ng: Retrieved Nov 30, 2023, from https://repository.mouau.edu.ng/work/view/comparative-studies-on-the-wort-properties-of-a-nigerian-grown-sorghum-malted-in-the-industry-and-in-the-laboratory-7-2

MLA 8th

ALOH, ALOH. "Comparative Studies On The Wort Properties Of A Nigerian Grown Sorghum Malted In The Industry And In The Laboratory" Repository.mouau.edu.ng. Repository.mouau.edu.ng, 15 Aug. 2023, https://repository.mouau.edu.ng/work/view/comparative-studies-on-the-wort-properties-of-a-nigerian-grown-sorghum-malted-in-the-industry-and-in-the-laboratory-7-2. Accessed 30 Nov. 2023.

MLA7

ALOH, ALOH. "Comparative Studies On The Wort Properties Of A Nigerian Grown Sorghum Malted In The Industry And In The Laboratory". Repository.mouau.edu.ng, Repository.mouau.edu.ng, 15 Aug. 2023. Web. 30 Nov. 2023. < https://repository.mouau.edu.ng/work/view/comparative-studies-on-the-wort-properties-of-a-nigerian-grown-sorghum-malted-in-the-industry-and-in-the-laboratory-7-2 >.

Chicago

ALOH, ALOH. "Comparative Studies On The Wort Properties Of A Nigerian Grown Sorghum Malted In The Industry And In The Laboratory" Repository.mouau.edu.ng (2023). Accessed 30 Nov. 2023. https://repository.mouau.edu.ng/work/view/comparative-studies-on-the-wort-properties-of-a-nigerian-grown-sorghum-malted-in-the-industry-and-in-the-laboratory-7-2

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