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

Abstract

The malting and brewing characteristics of millets (Pennisetum typhoides and Digitaria exilis) and sorghum (Sorghum bicolor) were compared. Diastase, α-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 ≥ 0.01. The major starch degrading enzyme in the three varieties of pearl millet (SE composite, SE.13 and SE 2124) was α-amylase. On the other hand, β-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, Digitaria exilis (“acha”) and sorghum (KSV-4), but inhibited the diastatic activities of sorghum (Farafara). Gibbereltic 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 exilis) had a high β-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.