African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5093

Full Length Research Paper

Evaluation of brewing potentials of grains, malts and worts of some sweet sorghum and sorghum varieties

Owuama, Chikezie I.
  • Owuama, Chikezie I.
  • Department of Microbiology, School of Life Sciences, Modibbo Adama University of Technology, Yola, Nigeria.
  • Google Scholar


  •  Received: 10 April 2019
  •  Accepted: 14 May 2019
  •  Published: 15 May 2019

Abstract

Little or no attention has so far been paid to using sweet sorghum malt for commercial beer brewing. Thus, three sweet sorghum varieties (SSV) and four sorghum varieties (SV) were analyzed for brewing quality. Variations were observed in their thousand grain weights (22.8 to 58.7 g), grain moisture contents (12.5 to 20.5%), germination energies (99.0 to 100%) and germination capacities (99.7 to 100%). After 4-day germination, radicle lengths of seedlings were 2 to 5 fold of plumules. Remarkable variations existed in their water sensitivity (7.1 to 27.6%) and grain protein contents (7.0 to 11.8%). Malts moisture contents (8.6 to 13.8%), malting losses (16.3 to 26.0%) and malts protein contents (12.2 to 19.5%) differed among cultivars. Cold water extracts (CWE) (3.8 to 8.8%) and hot water extracts (HWE) (8.8 to 17.5%) varied with cultivars. HWE were 1.5 to 3-fold of CWE. Diastatic powers (DP) were substantially higher in SSV (123.7 to 136.7º) compared to SV (111.8 to 117º). Amyloglucosidase (AMG) activities were detected in SSV malts but not in SV. α-Amylases activities in both SSV and SV malts were about 2 to 4-fold of β-amylases. Generally, DP in SV malts = α-amylase + β-amylase activities. But DP in SSV malts >α-amylase + β-amylase + AMG activities, thus, suggesting synergism between the enzymes. SSV showed similar wort yields with SV. Reducing sugars in wort of SSV (12.3 to 15.6 mg/ml) were higher than those of SV (6.2 to 10.5 mg/ml). Malts and worts analyses suggest that SSV have greater beer brewing potentials than SV.

Key words: Diastatic power, amylase, amyloglucosidase, sweet sorghum, malt, wort.