MBAA TQ http://dx.doi.org/10.1094/TQ-51-3-0901-01 | 
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Reginald C. Agu (1,2), Bartho N. Okolo (1), and Anny N. Moneke (1). 1. Department of Microbiology, University of Nigeria, Nsukka, Nigeria. 2. The Scotch Whiskey Research Institute, Research North Avenue, Riccarton, EH14 4AP, Scotland, United Kingdom.
Abstract
This study shows the differences in alcohol yields between the same millet variety grown at different periods and environment / locations, and highlights the importance of the two variables on cereal quality. Millet variety Pennisetum maiwa (grown in Nigeria in 2005) gave an alcohol yield of 462.22 liters of alcohol per metric ton (LA / t) dry weight basis (dwb). When P. maiwa was grown in 2013, it gave an alcohol yield of 441.94 LA / t (dry). The difference in alcohol yield when P. maiwa was grown in Nigeria in 2005 and 2013 was 20.28 LA / t dry. An alcohol yield of 413.45 LA / t (dry) was obtained from similar millet variety P. glaucum'Bajra' (grown in India in 2013). The difference in alcohol yield obtained from these millet samples grown at the two different locations in 2013 was approximately 29 LA / t (dwb). The study also established important links between alcohol yield obtained from millet and their residue viscosities. More alcohols were obtained when the substrates present in the cereal was extracted and converted to reducing sugars for yeast fermentation, causing a reduction in residue viscosity and vice versa. While all the millet samples studied looked exactly alike, their alcohol yield and residue viscosity results were different, indicating differences in the physiology of the three samples. Understanding the physiology of cereals is important when procuring raw materials for use in industrial processing. Environmental growing conditions, locations, and other batch-to-batch inconsistencies also need to be understood. Therefore, cereals should not be considered as “fixed quality commodities” as this study has shown. Such knowledge is important and will give good returns in terms of smooth and efficient processing, alcohol yield, and ultimately, profit.
Keywords: alcohol yield, cereals, environment, fixed commodity, location, millet, residue viscosity
Synthesis
This study shows the differences in alcohol yield of the same variety of millet grown at different times and in different locations / environment, and highlights the importance of these two variables on the quality of the cereal. The Pennisetum maiwa millet variety grown in Nigeria in 2005 yielded 462.22 liters of alcohol per metric ton (LA / t) dry weight. When P. maiwa was cultivated in Nigeria in 2013 it only had an alcohol yield of 441.94 LA / t (dry), for a difference of 20.28 LA / t. A yield of 413.45 LA / t (dry) was obtained with a similar variety of millet ( P. glaucum'Bajra'), grown in India in 2013. The difference in alcohol yield of these millet samples grown at different sites in 2013 was approximately 29 LA / t (dry). This study established that there are important links between the alcohol yield of a millet and the viscosity of its residue. More alcohol was obtained when the substrates present in the cereal were extracted and converted to reducing sugars by fermentation with yeast, causing a reduction in the residual viscosity, and vice-versa. Although all the millet samples studied appeared the same, their alcohol yields and residual viscosity results were different, indicating the existence of physiological differences in the three samples. It is important to understand the physiology of cereals when procuring raw material for industrial processing. The environmental conditions during its growth in the field, the cultivation sites and other inconsistencies from batch to batch must be taken into account. This study showed that cereals should not be considered as “fixed quantity commodities” (simple articles of consumption). This knowledge is important and its application will result in benefits in terms of smooth and efficient processing, higher alcohol yield and, in the long run, financial gains. This study showed that cereals should not be considered as “fixed quantity commodities” (simple articles of consumption). This knowledge is important and its application will result in benefits in terms of smooth and efficient processing, higher alcohol yield and, in the long run, financial gains. This study showed that cereals should not be considered as “fixed quantity commodities” (simple articles of consumption). This knowledge is important and its application will result in benefits in terms of smooth and efficient processing, higher alcohol yield and, in the long run, financial gains.
Keywords: cereals, environment, “fixed commodity,” millet, alcohol yield, site, residual viscosity
