THE BREWING POTENTIAL OF “ACHA” (DIGITARIA EXILIS) MALT COMPARED WITH PEARL MILLET (PENNISETUM TYPHOIDES) MALTS AND SORGHUM (SORGHUM BICOLOR) MALTS

Abstract

The malting and brewing characteristics of millets (Pennisetum typhoides and Digitarla exflia) and sorghum (Sorghum bicolor) were compared. Diastase, a-amylase, amyloglucosidase and proteases increased with malting time and the increase was associated with the modification. Development of hydrolytic enzymes was significantly higher in pearl millet and Digitaria exilis ("acha") than in sorghum at P 2 0.01. The major starch degrading enzyme in the three varieties of pearl millet (SE composite, SE.13 and SE 2124) was a-amylase. On the other hand, p-amylase was the major starch degrading enzyme in "acha" {Digitaria exilis) which is similar to the pattern in barley. Gibberellic acid had a stimulating effect on the diastatic activity of pearl millets, Digitarla exilis ("acha") and sorghum (KSV-4), but inhibited the diastatic activities of sorghum [Farafara). Gibberellic acid inhibited the proteolytic activities in all the pearl millet varieties, Digitaria exilis and sorghum varieties. Potassium bromate had little or no effect in the reduction of malting losses. Although "acha" {Digitaria exilia) had a high B-amylase content, a high malting loss makes it uneconomical to brew with "acha" mart. A blend of "acha" malt with pearl millet malt or sorghum malt (composite malt) will produce a malt of the same profile as barley malt and this will enhance the quality of sorghum and pearl millet malt during the mashing process. Wort quality of all the samples was suitable for brewing conventional beer.

Effect of Malting Conditions on Pearl Millet Malt Quality

“…These findings are in agreement with those of other authors working with sorghum 12,13,14,15,17,18,20,22 and millets 13,14,20,26 . Recently, Muoria and Bechtel 13 suggested that a germination temperature > 22°C would be more desirable for sorghum and pearl millet, than for barley, in order to obtain higher values of α-amylase.…”

“…The limited work on millet malting has been mainly on finger millet 1,8,9,10,14,24,26 with less being done on pearl millet. 6,11,13,20,25 The aim of this investigation was to determine optimum pearl millet malting conditions.…”

Effect of Germination Moisture and Time on Pearl Millet Malt Quality - With Respect to Its Opaque and Lager Beer Brewing Potential

“…Extract, as with DP, FAN and beta-amylase activity, increased with germination time. This is in agreement with findings for sorghum 6,15,20 , finger millet 17 and pearl millet 20 . The increase in hot water extract with germination time is an indication of the progress of modification (breakdown of the endosperm reserves, predominantly by amylase and protease activity) of the malt during germination 3 .…”

Developments on the cereal grains Digitaria exilis (acha) and Digitaria iburua (iburu)

“…The low-starch gelatinisation temperature (Jideani et al 1996) and high-beta-amylase activity (Nzelibe and Nwasike 1995;Nzelibe et al 2000) shows the brewing potential of acha and iburu in partial substitution of barley malt. Values are mean ± standard deviation; Means with different superscript within the same column differ significantly (p<0.05) using Duncan multiple range test Agu et al (2007) Constraints and opportunities for commercialisation…”