Effect of Experimental Variables on the Malting Performance of Nigerian Maize Oba Super 2 Variety

Background: The Nigerian cultivar, Oba Super 2 (OS2) maize is inexpensive but under- utilized owing to poor development of malting technology for brewing. Aim: To study the effects of experimental variables on the malting performance of Nigerian maize Oba Super 2 variety. Study Design: Exploratory. Place and Duration of Study: Department of Applied Microbiology and Brewing, Nnamdi Azikiwe University, Nigeria, between March, 2018 to September, 2019. Methodology: Certified Oba Super 2 maize variety was obtained from Premier Seed Limited, Zaria. The grain sample was malted at varying steeping (S) period (S30, S36 and S42 hours), different germination (G) period (0, 1, 2, 3, 4 and 5 days) and varying kilning (K) temperatures (45, 50 and 55°C) to determine the malting performance. The properties of the un-malted and malted maize were determined using standard methods. Data were analysed using analysis of variance (ANOVA) at P < 0.05. Results: The malting loss (ML) was significantly higher (P < 0.05) at different steeping period, on the fifth day of germination (G5). The cold water extract (CWE) was significantly higher (P < 0.05) on the fourth day of germination (G4) kilned at K50. The values for hot water extract (HWE) were significantly higher (P < 0.05) on the G4 at K45, K55 and K50, respectively, while free alpha amino nitrogen (FAN) values were significantly higher (P < 0.05) on the G4, all kilned at K50. The values for diastatic power (DP) were significantly higher (P < 0.05) on the G5, kilned at K50, while the cold water soluble protein (CWS-P) was significantly higher (P < 0.05) on the G3 kilned at K50. Conclusion: The results indicated that longer steeping and germination periods as well as moderate kilning temperature contributed maximally in improving the malting properties and high extract yields.

Production of Malt-based Sugar Syrup from Enzymatic Hydrolysis of Malted Sorghum and Millet Grains

The suitability of sorghum and millet grains in the production of malt-based syrups was determined. The grains were steeped for 50 h, germinated for 5 days at room temperature and were kilned for 48h to produce the malts. Mashing was carried out by three-stage decoction method and the resulting wort further hydrolysed with glucoamylase enzyme to yield malt syrups. Proximate analysis results showed that the crude protein contents in sorghum (11.3%) and millet (10.8%) malts were significantly (p < 0.05) higher than in sorghum (10.36) and millet (8.58%) grains. Cereal grains (sorghum, millet) were higher in fat (6.83, 7.30%), ash (2.41 and 3.16%), fibre (3.31 and 2.63%), moisture (9.93 and 9.95%) and total carbohydrate (71.63 and 53.35%) contents when compared with the malts. Results for malting characteristics of the grains showed that sorghum had significantly (p < 0.05) higher germinative energy (82.53%), germinative capacity (90.50%) diastatic power (32°L) and lower malting loss (13.50%) than millet grains: 76.6%, 85.67%, 27°L and 18.47% respectively. Mashing temperature and pH optima results for amylase activity were 60-70°C in sorghum, 40-450C in millet and pH 6-7 in sorghum and millet respectively. Results obtained on the analysis of the malt syrup samples (sorghum and millet) were (%): Moisture (12.35, 13.46), ash (0.02, 0.04), pH (4.5, 5.0), total solids (82.20, 80.1), Dextrose equivalent (85, 81) and reducing sugar (70.30, 65.45) respectively. Viscosity, colour and taste of the end products were physically checked. Sorghum grain exhibited better potential for syrup production.

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.

Preliminary study in improving the malting properties of Dawa, local Sorghum (Sorghum vulgare) variety.

Improving the malting properties of local sorghum [Dawa] (sorghum vulgare) was investigated. Malting is the germination of cereal gain in moist air under controlled conditions, the primary objective being to promote the development of enzymes which are not present in the ingeminated grain. Steeping, germination and kilning temperatures and conditions were altered to affect the improvement of the malt to be produced. Aseptic conditions were employed to avoid contamination of the process. A steeping regime of 52 hours was adopted. The steeping cycle involves 22 hours water steep and 8 hours air rest. Germination was done for 5 days during which enzymes development took place. Kilning was done in an oven for 24 hours at 500C so as to arrest germination. After these, grain and malt analyses were carried out. During the analyses, the following results were obtained: Moisture content (5.4%), thousand corn weight (28.5g), Germinative energy (95.5%), Germinative capacity (90%), cold water extract (44.8%), hot water extract (23%) and malting loss (13%). The result obtained shows that the sorghum variety had high malting loss which was attributed to the high germination temperature used. Also from the result, a Germinative capacity of 90% was gotten. This makes the sorghum (Dawa) variety a good grain raw material for brewing.

VARIETAL DIFFERENCES IN BARLEYS AND MALTS: XIV. INTERVARIETAL RELATIONS BETWEEN WORT PROPERTIES AND BARLEY AND MALT PROPERTIES

Data representing 24 barley varieties grown at six experimental stations in Canada were used to examine intervarietal relations among wort properties (degree of attenuation, viscosity, initial turbidity, final turbidity, and stability) and a number of barley, malting, and malt properties.The wort properties show significant associations with malt extract, saccharifying activity (Lintner value), and wort nitrogen, and also with barley salt-soluble nitrogen, hours steep, and malting loss, but they are not significantly related to barley starch, extract, or Lintner value after activation with papain. Degree of attenuation and stability increase, while viscosity and turbidity decrease, with increases in malt extract, saccharifying activity, wort nitrogen, barley salt-soluble nitrogen, and malting loss. It is concluded that the wort qualities are dependent on the development of enzymes in the growing barley and hence they reflect the extent of malt modification.Only one of the correlation coefficients is of such magnitude that a single malt property can be regarded as a measure of a wort property. This is the coefficient (r =.842) between wort nitrogen and wort viscosity. The other associations discussed, though significant, are loose, and it is concluded that wort properties cannot be adequately predicted from the commonly measured barley and malt properties.It is suggested that the results of quality tests on laboratory worts give information of value in assessing the quality of brewery worts.