[Comparison of 4 methods of evaluating protein quality in vegetable sources]

This study compares the practical value of the following methods: protein efficiency ratio (PER), blood urea concentration in rats (BUC), relative nutritive value (RNV), and predicted protein value (PPV) to evaluate the protein quality of 41 diets of plant origin. Results demonstrated low correlations between PER and RNV (r = 0.66), PER and PPV (r = 0.53), RNV and PPV (r = 0.54), whereas there was a high negative correlation between PER and BUC (r = -0.89). These different procedures can be useful and valid for distinct and well-defined objectives, but the evaluation of results must be made in accordance with the purpose of the experiment. In assessing the protein quality of foodstuffs, it is therefore recommended that mathematical computer models be developed which take into account the cybernetic system of the amino acid metabolism. This would definitely reduce the actual need of expensive long-term biological assays.