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The Problem of Curvature in Slope Assays for Protein Quality

  • J. Murray McLaughlan
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 105)

Abstract

The dose-response curves in a valid slope-ratio assay must be linear and meet at the zero protein dose. However in rat bioassays at least 3 types of curvature are found when the method is applied to a wide range of samples; the types of curvature result from: 1) excessive protein 2) lysine deficiency and 3) threonine deficiency. Whole wheat flour which was limiting in lysine and threonine showed marked downward curvature after supplementation with threonine. It can be argued from these results that the slope ratio and relative protein value method underestimated the protein quality of lysine-deficient foods.

Keywords

Wheat Flour Protein Quality Protein Efficiency Ratio Slope Ratio Limit Amino Acid 
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Copyright information

© Plenum Press, New York 1978

Authors and Affiliations

  • J. Murray McLaughlan
    • 1
  1. 1.Department of National Health and WelfareOttawaCanada

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