RESUMEN
The amount and quality of protein were determined in daily food rations of workers, including blue collar and white collar ones, which were reproduced in the laboratory on the basis of the data provided by the Central Statistical Bureau concerning the mean annual food consumption in 1986 (studies on household budgets). The amount of protein in the daily food ration of blue collar workers was higher (76 g) than in the families of white collar workers (68 g). The amount of energy provided by protein (12%) and the degree of coverage of the requirements for protein (mean 92%) were similar in both rations. The nutritional value of protein expressed as the NPU coefficient of protein utilization was relatively low in both rations (mean 66%). A comparison of these food rations in the years 1973, 1980, 1981 and 1986 showed that in 1980 the rations had the highest protein content (mean 93 g daily)--the highest proportion of protein-derived energy (mean 14%) and the highest proportion of protein requirement coverage (mean 120%). The nutritional value of protein (NPU, mean value 71%) was similar to that in 1973 and 1981. As compared to the preceding years the food rations in 1986 showed the lowest coverage of protein requirements and lower nutritional value as expressed with the NPUop index. A high correlation was found between the amino acid composition of dietary protein obtained by chemical analysis and those calculated from the Tables of Composition and Nutritional Value of Food Products.