CHEMICAL AND BIOLOGICAL EVALUATION OF GRAIN PROTEIN IN QUALITY PROTEIN MAIZE

Abstract

Quality protein maize (QPM) cultivars developed by Embrapa Milho e Sorgo (Brazil) were evaluated for profiles of essential amino acids and protein utilization using weanling male Wistar rats. Seven groups of six animals were kept in standard environmental conditions for ten days, and fed with either: a) a control diets (10% casein and 7% protein level), b) a non-protein diet, c) maize based diets with 7% protein (yellow QPM - BR 473, white QPM - BR 451 and common maize - BR 136), d) a mixed rice and bean diet with 10% protein (1:1 in protein base). Protein of QPM BR 473 and QPM BR 451 maize cultivars showed similar quality, which was superior (p < 0.05) to that of common maize, according to NPR (Net Protein Ratio - 3.37, 3.54 and 2.58, respectively to BR 473, BR 451 and BR 136) and NPU (Net Protein Utilization - 56%, 58% e 43%, respectively) indexes. Since QPM Brazilian cultivars have high protein value (an average of 83% compared to a reference protein) and show similar quality to the protein found in a rice and bean diet, its use should be encouraged in official Brazilian programs that aim to reduce malnutrition, particularly among poor children.

KEY WORDS: Corn, quality protein maize, protein value, QPM.