Malting of Finger Millet: Factors Influencing α-Amylase Activity and Wort Characteristics

The effect of germination temperature and duration and application of gibberellic acid on α-amylase activity and some wort characteristics of finger millet malt was studied. Two samples of finger millet were steeped to 33% moisture and germinated at 20, 25, 30, and 35° C for 48 and 96 hr with and without gibberellic acid (0.1 mg/kg). α-Amylase of the malts increased in response to higher germination temperatures (30–35° C). The α-amylase activity showed substantial decrease at the maximum mashing temperature of 70°C. The extract yield varied from 42.7 to 73.5% depending on malting conditions. The worts were light in color, low in soluble nitrogen, and filtered slowly. Reducing sugars were higher in the worts prepared from malts germinated at 30–35° C than those germinated at lower temperatures (20–25° C). Desirable free α-amino nitrogen levels (120–150 mg/L) in the worts were obtained from the malts germinated at higher temperatures for 48–96 hr. Malts treated with gibberellic acid and germinated at 30–35° C for 48 hr produced worts comparable to those of control malts germinated for 96 hr. Response to exogenous gibberellic acid was higher in the malts germinated at 30–35° C than in those germinated at 20–25° C.