Influence of malting conditions on sorghum (Sorghum bicolor (L.) Moench) as a raw material for fermented beverages

There has been recently increased interest in sorghum to substitute the gluten containing cereals in the diet of people suffering from celiac disease. The response surface methodology was used to determine the influence of malting parameters (degree of steeping, germination temperature and time) on sorghum (Sorghum bicolor (L.) Moench). Each parameter was varied at three levels. Malting attributes, considered important to produce high quality malt for the production of lactic acid fermented beverages, were analyzed. The optimized conditions were: degree of steeping 41%, germination temperature 27 after 7 days of germination. Under these conditions, the following values of the studied attributes can be obtained: aα-amylase 139U/g, β-amylase 60U/g, extract 83.8%, free amino nitrogen 117.8mg/100g, Kolbach index 26.6%, water-extractable arabinoxylan 0.3g/L and vitamin B2 114.9μg/L. Among the tested parameters, the germination time had the highest effect on malting attributes. Although the activity of amylolytic enzymes aα- and β-amylase were low, the value of extract was high and comparable to that of barley malt. The obtained results showed that sorghum malt is a promising raw material for the production of lactic acid fermented beverages.