Nigerian Sorghum Research Articles

Evaluation of the physico-chemical properties of cassava, cocoyam, sweet potato starches and glucose syrups produced from the hydrolysis of the starches with sorghum malt enzyme extract

Some physicochemical properties of starches from cocoyam, cassava and sweet potato were compared for suitability in glucose syrup production. Glucose syrups were produced from the starch slurry using 30 g of sorghum malt per 250 g starch weight. Malts were produced from Nigerian sorghum varieties; SFF- Sorghum ‘Farafara’ and SFD-Sorghum ‘Farindawa’ (Sorghumbicolor L. Moench). The grains were steeped for 24 h with 8 h air rest and germinated for 96 h. Results showed that malted SFD and SFF-sorghum grains recorded diastatic powers (61.45 and 52.32 DU.g-1), α-amylase (38.19 and 43.3 DU.g-1) and β-amylase (14.13 and 18.15 DU.g-1) activities, respectively. Cocoyam starch contained highest amylose (28.20%) when compared with sweet potato starch (22.50%) and cassava starch (20.40%). Solubility and swelling power of cassava, sweet potato and cocoyam starches were 17.2, 16.5 and 15.3 g.g-1 and 9.6, 6.2 and 7.6% at 90℃, respectively. Cocoyam starch showed the highest transition temperatures (69.5, 73.6, 82.3℃) and gelatinization enthalpy (17.3 J.g-1) than sweet potato (67.4, 71.3, 78.4℃, 12.3 J.g-1) and cassava (61.3, 65.5, 75.6℃, 13.4 J.g-1) starches. Dextrose equivalent for cassava, sweet potato and cocoyam glucose syrups were 40, 36, 30. Cassava starch glucose syrup obtained from SFD-malt hydrolysis met most of the Standard Organization of Nigeria set specifications.

AGRONOMIC PERFORMANCE OF FIVE SORGHUM VARIETIES IN A HUMID TROPICAL ZONE AS INFLUENCED BY FERTILIZER RATES

The phenology, growth and yield performance of four new varieties of sorghum as influenced by NPK 15:15:15 rates were evaluated in Awka, Anambra State Nigeria, a humid tropical zone. The new varieties, Improved Deko, SK-5912, KSV-8 and CSR-01 were evaluated alongside BidaLocal, an existing Nigerian sorghum landrace whereas NPK rates comprised 0, 200 and 400kg/ha. Experimental design was 3 x 5 factorial experiment in randomized complete block design(RCBD). The findings showed significant (P<0.05) interaction effect on phenology of sorghum. All the new varieties significantly flowered and matured earlier than the landrace. Earliestflowering (≈ 69 days) and grain maturity (≈ 111 days) were recorded in Improved Deko across the NPK rates whereas latest flowering (≈ 114 days) and harvest (≈ 154 days) were observed in Bida local. This implied that the Improved Deko flowered (45 days) and matured (43 days) earlier than the Bida Local across the NPK rates. Bida Local produced more number of leaves with wider stems than the new varieties especially at 90 days after planting while fewest number of leaves and narrowest stems were observed in Improved Deko. Although there was a progressive increase in growth (plant height, number of leaves, stem girth) with increase in NPK rates but the mean values recorded with 200 kg/ha NPK application were significantly at par with those obtained with 400 kg/ha NPK application. Highest panicle weight (67.5 g/plant) and grain yield (2.33 t/ha) were significantly (P<0.05) recorded in SK-5912 when the variety received 200 kg/ha NPK. This grain yield (2.33 t/ha) from SK-5912 was higher than the world average sorghum production (1.45 t/ha) Varieties SK-5912, KSV-8 and CSR-01 and Improved Deko had 145.84%, 50.26% and 35.09% grain yield increase with 200 kg/ha NPK when compared to the local variety. The results obtained from the study showed that SK-5912, KSV-8 and CSR-01 sorghum varieties can adapt favourably to a humid region of Awka agricultural zone of Anambra State, Nigeria especially when the soil is amended with 200 kg/ha NPK.

Phenotyping of Sorghum Lines for Resistance to African Stem Borer (Sesamia Calamistis)

Stem borer ( Sesamia calamistis ) is a serious insect pest of sorghum (Sorghum bicolor) resulting in grain yield losses ranging between 15-80%. However, genotypes showing complete resistance to these borers have not been identified in Nigeria. Utilization of resistant varieties in combination with other methods of control would offer a sustainable strategy for S. calamistis management in sorghum production. The objective of this study was to validate the acclaimed resistance in the materials received from Kenya and India in Nigerian environment and to screen and ascertain the status of some Nigerian Sorghum to Sesamia calamistis . Eighty-eight sorghum lines were artificially infested with the eggs of the stem borers at two different environment (Field and Screen House) using alpha-lattice design, consisting of 11 plots in eight blocks, replicated twice. Data were collected on leaf feeding, number of dead-hearts, cumulative stem tunnel length, number of exit holes, and selected agronomic traits. There were significant (p<0.01) differences among the test genotypes for all the traits measured. Based on the selection index, 15% of genotypes were categorized as resistant, 42% as moderately resistant,33 as moderately susceptible and 10% as susceptible.13 genotypes showed resistance across the environments (field and screen house): ICSB464, ICSL71086, SSV20041-2YELLOW, ICSL71018, ICSR94032, ICSV700, ICSL71193, ICSR94030, ICSL71253, ICSL71268, ICSL71023, ICSL71061 and ICSL71137 were resistant with selection index ranging from 0.0 to 0.5. These sorghum lines with various resistance to S. calamistis could be used as source of resistance and as parents in sorghum improvement programme in breeding for resistance to stem borer. Keywords: Genotypes, novel source of resistance, Sesamia calamistis , Sorghum bicolor DOI: 10.7176/JBAH/11-18-04 Publication date: September 30 th 2021

Effect of Steep Time and Regimen on the Diastatic Activity of Some Improved Nigerian Sorghum Cultivars

Effect of Steep Time and Regimen on the Diastatic Activity of Some Improved Nigerian Sorghum Cultivars

Effect of Different Steeping and Malting Regimen on the Amylolytic Activities of Some Improved Nigerian Sorghum Grain Varieties

Three Nigerian improved sorghum varieties were evaluated to ascertain how different steeping and malting regimen affect their amylolytic enzyme development. Steeping incorporated air rest and continuous steep regime for 72 h. Samples were withdrawn every 12 h. Germination was then carried out for four days before kilning at 50°C for 24 h. Grain and malt parameters were examined. Results obtained showed variations in the response of sorghum root length to steep regimen and time. CSR-02 gave maximum root length (3.32 cm) after 72 h of air rested steeping. CSR-02, Samsorg 44 and Samsorg 14 had germinative energies of 92.00 ± 4.24, 94.00 ± 1.41 and 96.00 ± 1.41%; germinative capacities of 91.00 ± 1.41, 75.50 ± 2.12 and 88.00 ± 2.83; water sensitivities of 6.50 ± 2.12, 13.50 ± 1.44 and 1.00 ± 0.41 respectively. TKW results were 29.73 ± 0.32, 33.85 ± 1.54 and 33.51 ± 0.41 kg for CSR-02, Samsorg 44 and Samsorg 14 respectively. Variations in the response of the sorghum varieties to various conditions of steep regime and steep period were also observed. Steeping for 48 h seems to be the optimum time for the development of amylolytic activity in all the sorghum varieties at both steeping regimens. Samsorg 14 gave the highest total amylase activity (355.44 µg glucose equivalents), followed by Samsorg 44 (278.08 µg glucose equivalents). Samsorg 14 also showed the highest α-amylase development (276.93 µg glucose equivalents). Air rest was found to be show greater effect on β-amylase development in all the sorghum varieties.

Partial Purification of a Catalase from an Improved Nigerian Sorghum Grain Variety

Catalases are key components of cellular detoxification pathways that prevent the formation of highly reactive hydroxyl radicals through catalyzing the decomposition of hydrogen peroxide into water and molecular oxygen. Their presence in brewery grains prevent the inactivation of important brewery enzymes and also stop lipid peroxidation. To determine their occurrence and establish some of its properties in sorghum, which has become as an important brewery grain similar to barley, crude catalase was obtained from a sorghum grain variety. Preliminary purification of catalase from the sorghum grain variety used, NRL-3, showed that the enzyme was purified 3.2-fold from the crude protein to give a 49% yield of the partially purified enzyme, with a final specific activity of 32 Umg-1 proteins. There was also a positive indication of sorghum catalase presence on SDS PAGE with positive bands occurring between the range of 48-62 kDa. Therefore, the molecular weight of sorghum catalase most likely falls within the two bands. The enzyme showed a narrow pH range with optimum activity occurring at pH 7. Similarly, its optimum activity temperature occurred at 40°C. This work is the first reported attempt at purifying catalase from sorghum.

Changes in the Activities of Alpha and Gluco-amylases during Malting of Some Improved Nigerian Sorghum Varieties

In this study changes in the alpha and glucoamylase activities of four different improved sorghum varieties were monitored over a 96-hour malting time to determine how the expression of the enzymes were affected by malting. Preliminary tests showed that SK5912 had the highest weight of 40 g/1000 grains and lowest malting loss of about 13%, while KSV 8 followed a weight of 36 g/1000 grains and the most malting loss of 22.6%. Enzyme results showed that the different sorghum varieties differed in their expression of the two of them across different malting regimes. However, all the varieties showed much higher expressions of glucoamylase than α-amylase at all the malting regime. Glucoamylase consistently showed its highest activities of over 71 U/ml across the four sorghum varieties after the first day of germination with variety SRNA giving the highest value slightly above 72 U/ml. The least glucoamylase activities were also given consistently across the four varieties by the unmalted raw grain. The highest α-amylase activities were generally shown across the four varieties after the third day of germination, with variety KSV 8 showing the highest value of about 14 U/ml. The control also gave the least α-amylase activities across all varieties with KSV8 giving the least. Considering the many important and multi-faceted roles that amylases are nowadays known to perform, the study of their expression dynamics in different plants and processes, one of which we report here, could help further the understanding of their characteristics and thus facilitate their maximal utilization.

Rheological, textural and nutritional properties of gluten-free sourdough made with functionally important lactic acid bacteria and yeast from Nigerian sorghum

Sorghum, being gluten-free, is often recommended as a safe food for celiac patients as gluten is associated with celiac disease. However, gluten absence in cereals causes technological inadequacies. Sourdough fermentation using functional starter cultures could produce desirable properties in gluten-free cereals. Sorghum flour was subjected to sourdough fermentation using functional lactic acid bacteria and yeast as starter cultures and their effects on the rheology, texture and nutritional properties of the sourdoughs were investigated. Pediococcus pentosaceus LD7 fermented sourdough had the highest storage modulus (G′) (3.07Pa) and loss modulus (G″) (6.23Pa), while P. pentosaceus SA8 sourdough had the least G′ (0.88Pa) and G″ (2.87Pa). Scanning electron micrograph of the sorghum sourdough breads revealed an intact and less porous cell structure in the samples containing starters in comparison to the control sample. The sourdough bread produced with P. pentosaceus SA8 and S. cerevisiae YC1 had the highest total dietary fibre (17.2%) but least protein content (4.9%). The starters modified the structure and nutrients of the sourdough where P. pentosaceus LD7 exhibited the most significant effect on the rheological properties. The study showed that the use of the selected starter cultures is useful in improving the structure and nutrient of sorghum-based gluten-free breads.

Changes in catalase activities during malting of some improved Nigerian sorghum grain varieties

The catalase activities of ten germinating improved sorghum varieties were monitored over a 4-day period to determine the effect of malting on them. This was done using standard methods that involved catalase assay at the appropriate experimental intervals. Results obtained showed that the different varieties of sorghum differed in their expression of catalase, a difference that was also reflected across the different stages of the malting process. The highest overall catalase activity (20.54 ± 0.74 U) was given by variety SK5912 after 72 hours of germination followed in second place by that from variety Nafelen (18.65 ± 0.99 U) obtained after steeping. The third and fourth highest value (17.88 ± 1.24 U and 17.08 ± 1.64 U) were given by KSV8 and Boboje after 72 and 48 hours of germination respectively. These values are probably indications that no single stage of malting was best for catalase expression among all the varieties. However, the fact that most of them (varieties ICSV 400, SK5912 and KSV 8, CSRO2 and ICSV III) all expressed their highest catalase activities after 72 hours of germination showed that 72 hours is probably the best germination stage for the elicitation of catalase among sorghum grains. The next best stage should be after 48 hours during which point three varieties (Boboje, NRL 3 and KAT 487) had their highest catalase activities. As a unity, all the sorghum varieties had their lowest catalase expression after 24 hours of germination, followed by those obtained after 96 hours germination. Keywords: catalase, sorghum, malting, peroxidase, cereal enzymes

Genomic Signatures of Adaptation to a Precipitation Gradient in Nigerian Sorghum.

Evolution of plants under climatic gradients may lead to clinal adaptation. Understanding the genomic basis of clinal adaptation in crops species could facilitate breeding for climate resilience. We investigated signatures of clinal adaptation in the cereal crop sorghum (Sorghum bicolor L. [Moench]) to the precipitation gradient in West Africa using a panel (n = 607) of sorghum accessions from diverse agroclimatic zones of Nigeria. Significant correlations were observed between common-garden phenotypes of three putative climate-adaptive traits (flowering time, plant height, and panicle length) and climatic variables. The panel was characterized at >400,000 single nucleotide polymorphisms (SNPs) using genotyping-by-sequencing (GBS). Redundancy analysis indicated that a small proportion of SNP variation can be explained by climate (1%), space (1%), and climate collinear with space (3%). Discriminant analysis of principal components identified three genetic groups that are distributed differently along the precipitation gradient. Genome-wide association studies were conducted with phenotypes and three climatic variables (annual mean precipitation, precipitation in the driest quarter, and annual mean temperature). There was no overall enrichment of associations near a priori candidate genes implicated in flowering time, height, and inflorescence architecture in cereals, but several significant associations were found near a priori candidates including photoperiodic flowering regulators SbCN12 and Ma6. Together, the findings suggest that a small (3%) but significant proportion of nucleotide variation in Nigerian sorghum landraces reflects clinal adaptation along the West African precipitation gradient.

Evaluation of functionally important lactic acid bacteria and yeasts from Nigerian sorghum as starter cultures for gluten-free sourdough preparation

There is an increasing prevalence of celiac disease, which is gradually encroaching into Africa and Nigeria ranks first among sorghum-producing African countries. It is important to select starter cultures that can improve the functional properties of peculiar flour such as sorghum for the development of novel gluten-free diets. Therefore, this study aimed at screening of functionally important lactic acid bacteria (LAB) and yeasts as starter cultures for the development of sorghum-based sourdough. A total of 103 LAB and 20 yeast isolates obtained from Nigerian sorghum flour were screened for functional properties essential for sourdough preparation. Three LAB isolates were selected based on proteolytic activities, exopolysaccharide production and acidification properties, while one yeast strain was selected based on its gas production ability, low pH and acetic acid tolerance. Pediococcus pentosaceus SA8, Weissella confusa SD8 and P. pentosaceus LD7 showed highest proteolytic activity (24.7 mm), exopolysaccharide production (753.3mg/100 ml) and acidification property (0.25 g/100 g lactic acid) respectively. Saccharomyces cerevisiae YC1 had vigorous gas production (CO2 > 20 mm at 8 h), tolerated pH 2.5 and 0.1% acetic acid, and had highest leavening activities (60.87% at 1 h). The selected LAB and yeast strains possessed promising attributes as functional starter cultures for the production sourdoughs breads.

Utilization of whole sorghum crop residues for bioethanol production

Sorghum is the fifth most important cereal worldwide and is a major source of agricultural residues in tropical regions. Bioconversion of whole sorghum crop residues comprising stalks, leaves, peduncles and panicles to ethanol has great potential for improving ethanol yield per sorghum crop cultivated, and for sustainable biofuel production. Effective pretreatment of sorghum lignocellulosic biomass is central to the efficiency of subsequent fermentation to ethanol. Previous studies have focused on the bioconversion of sorghum stalks and/or leaves only to bioethanol, but the current study is the first report dealing with whole crop residues. We specifically focused on the impact of Nigerian sorghum cultivation location and cultivar type on the potential ethanol yield from whole sorghum crop residues. Efficient bioconversion of whole sorghum residues to ethanol provides a sustainable route for utilization of crop residues thereby providing a non-food feedstock for industrial-scale bioethanol production. Copyright © 2016 The Institute of Brewing & Distilling

Bioconversion of degraded husked sorghum grains to ethanol

AbstractEfficient starch saccharification is an essential step towards achieving improved ethanol yields by fermentation. Sorghum grains are important starch sources for bioconversion to ethanol. In the present study, disease degraded (spoilt) husked grains from Nigerian sorghum cultivars were obtained from field sites and subjected to bioprocessing to ethanol. The crude husked grains (comprising husks, spikelet, awn, rachis and pubescence materials) were hammer milled and each meal separately mashed with enzyme cocktails comprising amylase, glucanase and protease enzymes. The saccharified worts obtained were then fermented with the yeasts, Saccharomyces cerevisiae and Pichia stipitis (aka Scheffersomyces stipitis), without exogenous nutrient supplementation. Sugars liberated during mashing were determined and it was found that enzymatic hydrolysis of milled sorghum grains was effective in yielding favourable levels of fermentable sugars up to 70g sugar/100g substrate with one particular cultivar (KSV8). Ethanol and carbon dioxide production was measured from subsequent trial fermentations of the sorghum mash and it was found that S. cerevisiae produced ethanol levels equating to 420 L/t that compares very favourably with yields from wheat and barley. Our findings show that crude degraded sorghum grains represent favourable low-cost feedstocks for bioconversion to ethanol with reduced energy input and without additional costs for nutrient supplementation during fermentation. Consequently, our results suggest some economic benefits could be derived from spoilt or degraded sorghum grains.

Improved production of ethanol using bagasse from different sorghum cultivars

For improved production of ethanol from whole sorghum residues, physico-chemical compositions and fermentation characteristics of the substrates are important factors to consider. In the present study, Nigerian sorghum cultivars SSV2, KSV8 and KSV3 were grown under rain-fed conditions without chemical fertilization in Kano state, Nigeria. On harvest, the whole sorghum residues (bagasse) comprising crushed stalks, leaves, panicles and peduncles were collected for further processing. Bagasse samples, which had different macromolecular composition and carbohydrate pasting properties, were pre-treated with dilute sulphuric acid at 75 °C followed by enzymatic hydrolysis and sequential detoxification by Ca(OH)2 over-liming and charcoal filtration. Hydrolysate samples were subsequently fermented with the yeasts, Saccharomyces cerevisiae and Pachysolen tannophilus. Sugar consumption, carbon dioxide evolution and ethanol production were shown to vary depending on the sorghum cultivar type. While KSV3 yielded most favourable biomass of 37 t ha−1 (dry basis), bagasse from cultivar SSV2 yielded the most favourable level of sugars (69 g/100 g) after enzymatic hydrolysis, and also consistently exhibited improved fermentation performance. Detoxification of pre-treated sorghum bagasse to remove potential yeast inhibitors resulted in improvement in ethanol yield, with 23 g L−1 ethanol (representing 72% of theoretical yield) being achieved from SSV2 bagasse following fermentation with P. tannophilus without exogenous nutrient supplementation. Our findings reveal that the choice of sorghum cultivar is important when converting bagasse to ethanol, and further that pretreatment with dilute acid at moderate temperature followed by detoxification improves fermentation kinetics and ethanol yield.

Grain and malt quality properties of some improved Nigerian sorghum varieties

To determine their grain and malt quality properties, ten improved Nigerian sorghum varieties were subjected to several tests. The parameters that were tested included thousand corn weight, germinative energy, germinative capacity, water sensitivity, malting losses, hot and cold water extracts and free amino nitrogen (FAN). Results obtained showed variations among the sorghum varieties in most of the parameters assessed. While variety SK5912 was heaviest (40.25 g), variety Nafelen 6 had the lowest weight (22.45 g). For germinative capacity, variety KSV8 gave the highest value (97.0%), while variety ICSV400 gave the lowest value (90.5%). Variety KAT487 was the most water sensitive (5%), while four varieties simultaneously gave the lowest value. Boboje gave the lowest malting loss (13.77%), while the highest loss (37.74%) was given by White Kaura. For the extracts, variety SK5912 gave the highest value, as was the case also with FAN. Generally, there were significant differences across the different varieties of sorghum for malting loss, FAN, cold water extract and hot water extract at both p < 0.05 and p < 0.01. The results showed significant agreement with previous reports, with the key findings being that grain size mostly correlated positively with high expression of the critical malting parameters. Copyright © 2014 The Institute of Brewing & Distilling

Impact of Unmalted White Nigerian and Red Italian Sorghum (Sorghum Bicolor) on the Quality of Worts and Beers Applying Optimized Enzyme Levels

Brewing with sorghum adjunct is well established in many countries, such as Nigeria. However, no brewing-related publications based on the use of unmalted sorghum grown in Europe are available to date. Therefore, the objectives of this study were to determine and compare the impact of 40% white Nigerian and red Italian sorghum on wort and beer quality adding optimized levels of exogenous enzymes. Brewing with sorghum adjunct was carried out in a 60-L pilot plant applying a double infusion mashing process. Worts and beers were analyzed with regard to processability, flavor and sensory characteristics, foam stability, shelf life, and gluten content (competitive ELISA). The substitution of 40% barley malt with white or red sorghum caused significant increases in wort pH as well as significant decreases in wort viscosity (calculated to 12.0% w/w extract), TSN, FAN, and total amino acids. Worts produced with 40% red sorghum contained higher levels of total polyphenols and total fermentable sugars than those produced with 40% white sorghum. Beers brewed with 40% unmalted sorghum exhibited significantly lower foam stabilities compared with 100% barley malt beers. However, white sorghum had a considerably less adverse impact on beer foam than red sorghum. The sensory analysis performed according to the Deutsche Landwirtschafts-Gesellschaft e.V. (DLG) scheme revealed no significant differences between 40% sorghum and 100% barley malt beers. Furthermore, the gluten content of beers was significantly reduced by replacing 40% barley malt with sorghum adjuncts. According to the Codex Alimentarius, red sorghum beer could even be labeled as a “very low gluten” beverage.

A Comparison of White Nigerian and Red Italian Sorghum (Sorghum Bicolor) as Brewing Adjuncts Based on Optimized Enzyme Additions

Sorghum has been used for thousands of years in human food products. In Western countries, however, it is primarily used as bird and animal feed, although there is considerable interest in its use as gluten-free alternative to wheat, barley, and rye. The aim of this study was to compare the mashing performance of white Nigerian and red Italian sorghum based on optimized enzyme additions. For this purpose, both sorghum types were fully characterized using standard methods, Lab-on-a-Chip capillary electrophoresis, and scanning electron microscopy. The application of exogenous enzymes was optimized by monitoring changes in mash consistency during mashing using a Physica MCR rheometer. Furthermore, laboratory-scale mashing trials were carried out to compare the quality of worts produced with up to 40% white or red sorghum and optimized enzyme levels. Both sorghum types are characterized by higher starch and lower protein/β-glucan contents in comparison to barley malt. The addition of protease/β-glucanase as recommended had no significant effect on mash consistency and wort quality. Besides, 50% of the recommended heat-stable α-amylase dose was sufficient for 40% sorghum adjunct. Worts produced with 40% white or red sorghum had significantly lower TSN/FAN contents and viscosities than the reference wort (100% barley malt). However, white sorghum provided significantly more TSN/FAN compared to red sorghum. Its use as a substitute for barley malt also resulted in significantly higher extract contents.

Fermentation of stalk juices from different Nigerian sorghum cultivars to ethanol

For improved production of ethanol from sorghum stalk juice fermentation, cultivation location and cultivar type are important factors to consider. In the present study, SSV2 and KSV8 sorghum cultivars were cultivated in Kano and Kaduna states in Nigeria that exhibit notably different rain precipitation and diurnal temperatures. The crude stalk juices (without pre-treatment or nutrient supplementation) were extracted from these sorghum samples and fermented with a distiller's strain of the yeast, Saccharomyces cerevisiae. Sugar consumption and alcohol production were determined by HPLC and GC-MS, respectively. When it was grown in the Kaduna site, SSV2 was identified as the highest yielding sorghum cultivar from which we extracted the maximum levels of extractable sugars (161.50 g l -1 ) that yielded favourable ethanol levels of 80.56 g l -1 following fermentation. Our findings show that relatively colder and wetter cultivation sites are preferred for sorghum stalk juice destined for bioethanol production.

A Comparison of White Nigerian and Red Italian Sorghum (Sorghum bicolor) as Brewing Adjuncts Based on Optimized Enzyme Additions

A Comparison of White Nigerian and Red Italian Sorghum (Sorghum bicolor) as Brewing Adjuncts Based on Optimized Enzyme Additions

Current Developments in Malting and Brewing Trials with Sorghum in Nigeria: A Review

Initially, large-scale lager beer brewing with sorghum malts proved highly intractable due to a number of biochemical problems including: high malting losses estimated at 10–30% as against 8–10% for barley; high gelatinisation temperatures which limited starch solubilisation/ hydrolysis by the amylolytic enzymes during mashing; low extract yield/low diastatic power (DP) due to inadequate hydrolytic enzyme activities especially β-amylase; low free α-amino nitrogen (FAN) due to inadequate proteolysis limiting yeast growth during fermentation; high wort viscosities/beer filtration problems due to low endo-β-1,3; 1–4-glucanase activities on the endosperm cell walls causing the release of some β-glucans. Strident research efforts using improved Nigerian sorghum malt varieties (SK5912, KSV8 and ICSV400) have reported some encouraging results. The knowledge of the biochemical integrity of the endo-β-glucanases of the sorghum malt is helping to elucidate their mode of activity in the depolymerisation of the β-glucans. This is bound to ensure process efficiency in sorghum beer brewing, reduce beer production costs and ultimately, produce a Pilsner-type of lager beer with 100% sorghum malt.