title: Hardness as a modification index for malting red and white sorghum (kaffir) grains.
abstract: BACKGROUND
  This study investigated changes in the resistance to fracture of malting red and white sorghum grains using a hardness tester as another method for monitoring grain modification.
  
  
  RESULTS
  Grain hardness decreased progressively from 134.35 N and 137.29 N in malting red and white sorghums and levelled off after 120 h at 76.98 N and 69.14 N. In the red grain malts traditionally used for burukutu production, moisture content (r = -0.983), dhurrinase activity (r = -0.981), malting loss (r = -0.981), free amino nitrogen (r = -0.909) and cold water extract (r = -0.908) were better indicators of grain hardness than root length (r = -0.89). In the white sorghum malts, malting loss (r = -0.988), dhurrinase activity (r = -0.954) and diastatic activity (r = -0.936) were better indicators of grain modification than root length (r = -0.916). The soluble nitrogen ratio at the end of malting was lower in the red (0.049) compared with the white (0.0548).
  
  
  CONCLUSIONS
  Grain hardness using a hand-held tester is a simple, fast and good index of modification of malting red and white sorghum grains. Oven-dried red and white sorghum malts could be considered to be well modified at hardness values/indices below 77 N/0.5730 and 72 N/0.5036, respectively.
authors.affiliation: Department of Food Science and Technology, University of Nigeria, Nsukka, 410001, Nigeria.
authors.forename: Peter O
authors.initials: PO
authors.lastname: Uvere
authors.forename: Patrick O
authors.initials: PO
authors.lastname: Ngoddy
authors.forename: Chibuzo S
authors.initials: CS
authors.lastname: Nwankwo
mesh_terms: D000681:Amylases / Q000378:metabolism; D004044:Dietary Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D005511:Food Handling; D005513:Food Inspection / Q000379:methods*; D063427:Food Quality; D018525:Germination; D006244:Hardness; D055595:Mechanical Phenomena; D009549:Nigeria; D010446:Peptide Fragments / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D010858:Pigmentation; D010940:Plant Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D018517:Plant Roots / Q000254:growth & development; D059748:Proteolysis; D012639:Seeds / Q000737:chemistry* / Q000201:enzymology / Q000254:growth & development; D012995:Solubility; D045868:Sorghum / Q000737:chemistry* / Q000201:enzymology / Q000254:growth & development; D013045:Species Specificity; D014867:Water / Q000032:analysis; D001617:beta-Glucosidase / Q000378:metabolism
chemical_list: D004044:Dietary Proteins; D010446:Peptide Fragments; D010940:Plant Proteins; D014867:Water; D000681:Amylases; C411650:Dhr1 protein, Sorghum; D001617:beta-Glucosidase
keywords: hardness; malt; modification indices; sorghum