Journal of the American Oil Chemists Society · 2003 · 339 citations · 11 references
AgricultureAgronomyFood ScienceFood AnalysisFood ChemistryHuman NutritionNitrogen NutritionProtein AnalysisProtein CharacterizationProtein QualityProteins In FoodsFood Protein CompositionNitrogen Content AnalysisNitrogen Content EstimationProtein Content AnalysisProtein Content DeterminationProtein Quality AssessmentSeed Protein QualityTotal Kjeldahl Nitrogen
Abstract The Kjeldahl and Dumas methods for quantifying nitrogen content were compared using nine soybean products having protein contents ranging from 0.5 to 90%. In addition to comparing day‐to‐day variability of the Dumas method, differences between and variabilities of two Kjeldahl systems and Kjeldahl operators were also evaluated. The Kjeldahl method gave slightly, but significantly, lower values than did the Dumas method. Both the Kjeldahl and Dumas methods had equivalent variabilities (same SD about the means). The ratios between the means for the Kjeldahl and Dumas (K/D) protein values ranged from 0.66 to 1.03. The conversion equation y =−0.00536+0.97188 x ( R 2 =0.9997) was developed and validated to convert from Dumas to kjeldahl protein concentrations.
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