COMPARISON OF Tetrahymena pyriformis W AND RAT BIOASSAYS FOR THE DETERMINATION OF PROTEIN QUALITY

Abstract

ABSTRACT The protein quality of 34 samples of commercially prepared foods was determined using the Tetrahymena pyriformis W and rat Protein Efficiency Ratio (PER) bioassays. ANRC Reference Casein was used as the reference protein in both assays. The regression equation relating the Tefrahymena Relative Nutritive Value (RNV) and PER was: PER = 0.286 + 0.022 (RNV), r = 0.90 (P < 0.01). This relationship could be used to predict the protein quality of food samples. The use of the Coulter particle counter instead of the direct microscopic counting procedure increased the efficiency of the Tetrahymena assay by reducing counting error and the length of time required. In addition, quantitative information on cell size in relation to quality and quantity of protein in the test sample was obtained. The results of these studies suggest that the Tetrahymena pyriformis W assay may be adapted to provide a rapid, low cost assay for estimation of protein quality of commercially prepared foods.