Comparative Studies On The Wort Properties Of A Nigerian Grown Sorghum Malted In The Industry And In The Laboratory
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
0.0
ALOH, A (2023). Comparative Studies On The Wort Properties Of A Nigerian Grown Sorghum Malted In The Industry And In The Laboratory. Mouau.afribary.org: Retrieved Sep 19, 2024, 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
ALOH, ALOH. "Comparative Studies On The Wort Properties Of A Nigerian Grown Sorghum Malted In The Industry And In The Laboratory" Mouau.afribary.org. Mouau.afribary.org, 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 19 Sep. 2024.
ALOH, ALOH. "Comparative Studies On The Wort Properties Of A Nigerian Grown Sorghum Malted In The Industry And In The Laboratory". Mouau.afribary.org, Mouau.afribary.org, 15 Aug. 2023. Web. 19 Sep. 2024. < 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 >.
ALOH, ALOH. "Comparative Studies On The Wort Properties Of A Nigerian Grown Sorghum Malted In The Industry And In The Laboratory" Mouau.afribary.org (2023). Accessed 19 Sep. 2024. 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