Studies on the Malting Parameters of Two Acha Species Digitaria exilis and Digitaria iburua

The malting parameters of two acha species (Digitaria exilis-white and Digitaria iburua-black), a small annual herbaceous indigenous African cereal grain were studied. This study was aimed at assessing the brewing potential of the two acha species. The research was carried out in Microbiology Laboratory of Nnamdi Azikiwe University, Awka. The brewing properties assessed were; moisture content, cold water extract, hot water extract, diastatic power, total nitrogen, cold water soluble protein, total soluble protein and free amino nitrogen. Extraction, digestion, titration, colorimetric and spectrophotometric methods were used to assess the above brewing properties. The moisture content of the white species malt (11.0 - 12.4%) was higher than that of the black (10.3 – 11.2%) and increased with germination time but decreased after the peak (4th) day. The lower moisture content of the black acha malts gave a resultant effect of more extract production from cold water extract ( CWE 27.5, 30.10%), hot water extract (HWE 278, 304ol/kg) and diastatic power (DP 19 ,23oL) of the two acha malts on the fourth (peak) day of germination. The peak values for total nitrogen (1.6, 1.75%), cold water soluble protein (120, 128%), total soluble protein (6.2, 7.5%) and free amino nitrogen (FAN 105, 114.5%) were also higher for the black acha on the peak day of germination. The correlation studies between the HWE (R2=0.9903, 0.9551), Cold water soluble protein (CWS-P- R2= 0.9809, 0.9285) and Diastatic power for the black and white species, respectively, were positively significant depicting a strong relationship between the correlated parameters. The black acha malt recorded more extract yield than the white acha and the result of the two acha species assessed showed that they possess brewing properties.