Assessment of malting performance of landrace six-row Arupo S Barley adapted to grow in tropical Nigeria

An adapted, landrace Nigerian Arupo S barley was malted in the laboratory following the standard malting method developed for malting elite barleys. Our results showed that Arupo S barley showed both fast and even germination during the malting process. Friability results further established that Arupo S malted barley produced flours with high amounts of husks. This is an advantage for both the brewing and distilling industries in terms of wort filtration for the brewing industry or phenol retention during peating or kilning for the distilling industry. The proteolysis achieved when Arupo S barley was malted by using standard malting procedures for malting elite barleys showed that a progressive increase in the pattern of release of soluble nitrogen materials in terms of free amino nitrogen (FAN) and amino acid production was achieved. FAN released in Arupo S malt was 118 mg/L on day 4 of the germination period and was sufficient to support yeast fermentation. The amino acids released into the worts of mashed Arupo S malt were generally high. Extracts from mashed Arupo S malt produced a similar range of reducing sugars (glucose, sucrose, fructose, maltose, and maltotriose) found in standard (elite) malted barley varieties. Fermentability results showed that Arupo S malted barley produced maximum predicted spirit yield on day 4 of malting. This study also showed that for the brewing industry, Arupo S malted barley produced good head retention. Our results clearly showed that although the Arupo S six-row barley studied was grown in a hot tropical environment with irrigation (drought and flooding) and was malted using methods developed for malting temperate-grown elite barleys, it still produced overall results comparable to those obtained for adequately researched barleys. A genetic variability that enabled Arupo S barley to grow and produce crops under these harsh environmental conditions, as well as to produce malt, is worth exploring.