AMINO-ACID CONTENT AND PROTEIN BIOLOGICAL EVALUATION OF 12 MEXICAN VARIETIES OF RICE

Protein efficiency ratio (PER) and amino acid content were determined in brown and polished samples of 12 varieties of Mexican rice. All sam ples of the polished rice presented lysine as the limiting amino acid with a chemical score ranging from 46 to 57. The amino acid content of the brown rice samples was similar to that of the polished rice sampl es for each variety. Again, the limiting amino acid was lysine, except in Sinaloa A-80 and CICA-6, which presented isoleucine as the limitin g amino acid. The protein quality of the brown and the polished rice s amples was similar for each variety. Only Sinaloa A-80 and CICA-6 brow n rice samples presented a PER lower than that of their corresponding polished rice samples. The adjusted PER for the polished rice samples ranged from 2.23 (CICA-6) to 1.30 (Cardenas A-80). The adjusted PER fo r the brown rice samples ranged from 2.20 (Morelos A-83) to 1.47 (Card enas A-80). According to these results, the varieties that showed the best protein quality were CICA-6, Morelos A-83, and Navolato A-71 (pol ished samples). In addition, Navolato A-71 (polished samples) presente d the highest protein content (11.6%, db). Thus, Navolato A-71 was the best variety of the Mexican rices studied and could have an important nutritional impact if its consumption becomes generalized.