Biochemical quality indices of sorghum genotypes from east Africa for malting and brewing

  • Felix K Kiprotich
  • Erick K Cheruiyot
  • Charles M Mwendia
  • Francis N Wachira
  • James Owuoche

Abstract

There is a gradual shift to substitute barley with sorghum in brewing industry to reduce the cost of doing business and make beer products more competitive. This study evaluates the sorghum genotypes for desirable malting and brewing characteristics. Biochemical characteristics assayed for 131 sorghum [Sorghum bicolor (L) Moench] accessions included total starch, amylopectin, amylose, proteins, tannins contents, germination energy and germination capacity. Results indicate that starch contents ranged from 22.8 - 81.2%, amylose from 11.5 - 30.2% while the amylopectin content ranged from 6.6 - 59.8%. Generally, amylose contents of sorghum genotypes were lower than their amylopectin contents, with a ratio of 1:2. The mean protein content for the sorghum accessions was 9.4% with a range of 3 - 18%, while that of barley was from 7.7 - 9.8%. Germination energy and germination capacity for sorghum ranged from 82.9 - 99.8% and 74.0 to 99.5%, respectively. Barley varieties showed germination energy and capacity greater than 98%. Sorghum tannin contents ranged from 2.55 mg/100 ml to as high as 100 mg/100 ml while barley varieties had tannin contents of 8.9 to 10.3 mg/100 ml. Two genotypes, SDSA 1x ICSR 43 and SP 993520-1 were the most favorable for brewing.

Keywords: Sorghum, starch, protein, tannin, germination energy, malting and brewing

African Journal of Biotechnology, Vol. 13(2), pp. 313-321, 8 January, 2014

Author Biographies

Felix K Kiprotich
Egerton University, Department of Biochemistry and Molecular Biology, P.O Box 536-20115, Egerton, Kenya
Erick K Cheruiyot
Egerton University, Department of Crops, Horticulture and Soil, P.O Box 536-20115, Egerton, Kenya
Charles M Mwendia
Egerton University, Department of Biochemistry and Molecular Biology, P.O Box 536-20115, Egerton, Kenya
Francis N Wachira
Association for strengthening Agricultural Research in Eastern and Central Africa (ASARECA) P.O Box 765, Entebbe, Uganda
James Owuoche
Egerton University, Department of Crops, Horticulture and Soil, P.O Box 536-20115, Egerton, Kenya
Published
2015-05-18
Section
Articles

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eISSN: 1684-5315