title: Total and reactive lysine contents in selected cereal-based food products.
abstract: The aim of the study was to determine and compare reactive and total lysine contents in a range of breakfast cereal products. Crude fiber, fat, ash, and crude protein contents of 20 breakfast cereal products ranged from 4 to 38, 14 to 144, 7 to 32, and 52 to 253 g/kg, respectively. The concentrations of glutamic acid (18.7-32.1 g/100 g protein) and proline (4.7-10.8 g/100 g protein) were high while those of the amino acids methionine (1.2-2.0 g/100 g protein) and histidine (1.2-3.3 g/100 g protein) were relatively low. There was a strong relationship between reactive lysine determined using the guanidination and fluorodinitrobenzene methods (R = 0.99). The total lysine content, determined after conventional acid hydrolysis, ranged from 0.8 to 3.7 g/100 g protein, while the reactive lysine content (guanidination) ranged from 0.4 to 2.8 g/100 g protein. Reactive lysine was 20-54% lower than total lysine in the cereal products. The large differences between total and reactive lysine suggest a considerable loss of lysine in the breakfast cereals tested.
authors.affiliation: Department of Animal Science, Gorgan University of Agricultural Sciences & Natural Resources, Iran.
authors.forename: Nour Mohammad
authors.initials: NM
authors.lastname: Torbatinejad
authors.forename: Shane M
authors.initials: SM
authors.lastname: Rutherfurd
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Moughan
mesh_terms: D000596:Amino Acids / Q000032:analysis; D004041:Dietary Fats / Q000032:analysis; D004043:Dietary Fiber / Q000032:analysis; D004044:Dietary Proteins / Q000032:analysis; D004139:Dinitrofluorobenzene / Q000737:chemistry; D002523:Edible Grain / Q000737:chemistry*; D019791:Guanidine / Q000737:chemistry; D008239:Lysine / Q000032:analysis* / Q000737:chemistry
chemical_list: D000596:Amino Acids; D004041:Dietary Fats; D004043:Dietary Fiber; D004044:Dietary Proteins; D004139:Dinitrofluorobenzene; D019791:Guanidine; D008239:Lysine