Difficulties in Assessing the Nutritional Quality of Rice Protein

Abstract

The biological assessment of protein quality is difficult in samples which contain relatively little protein. The difficulty is particularly severe in samples which contain protein of poor quality and, especially so, if the protein is limiting in lysine. Typical difficulties likely to be encountered are exemplified in assays of the nutritive quality of rice proteins. It is concluded that in the samples tested the relative nutritive value (RNV) of the rice protein varied from approximately 50 to 80% compared to lactalbumin, and was negatively correlated with total protein content. The net utilizable protein, however, rose with total protein content between 6 to 10% protein, the fall in RNV being more than compensated for by the increase in total protein. The response per unit lysine consumed in these samples, all of which were limiting in lysine, does not appear to be constant indicating difficulties in the interpretation of chemical score.