Quality Protein Maize

Cereals have low confenfs of essential amino acids, particularly lysine and tryptophan. In developing countries especially, this creates nutritional deficiencies for a large proportion of the population because a single cereal may account for a major part of the protein intake. In some countries (Central and South America and sub-Saharan Africa), people rely on maize as their principal food. In order to counter the problem, high-lysine mutants of maize have been identified. However, these mutants are associated with negative effects on yield and they have soft, chalky kernels that are susceptible to disease and insect damage. 

An account of how the research evolved can be found in Prasanna et al. (2001). An updated review of the topic has been given by Gupta et al. (2009). The QPM maize germplasm has now been dispatched to different countries around the world and has had a great influence in improving the nutrition of a large number of people as well as animals. 

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Graham, G. G., Lembcke, J., Lancho, E., and Morales, E. (1989). Quality protein maize Digestibility and utilization by recovering malnourished infants. Pediatrics 83, 416-421. 

Gupta, H. S., P. K. Agrawal, V. Mahajan, G. S. Bisht, A. Kumar, P. Verma, A. Srivastava, R. Babu, M. C. Pant, and V. P. Mani. 2009. Quality protein maize for nutritional security Rapid development of short duration hybrids through molecular marker assisted breeding. Current Science 96 230-237. 

RP-HPLC is especially valuable in genetic studies of maize. Paulis et al. [175] showed that prolamin RP-HPLC differentiates normal, opaque-2, and modified opaque-2 genotypes differing in nutritional quality and endosperm texture. Modified opaque-2 maize genotypes ( quality protein maize ) are enriched in high-proline alcohol-soluble glutelin subunits and contain less zein than normal maize. 

RP-HPLC of storage proteins can also predict quality in other cereals. In barley, RP-HPLC of hordeins [112,224] and high-MW glutelins [225] can reveal malting quality. In maize, Paulis et al. [226] showed by RP-HPLC that there are more y-zeins in quality protein maize than in normal maize this relates to lysine content and nutritional quality. RP-HPLC can relate protein composition to kernel hardness, density, and vitreosity of both normal maize and quality protein maize genotypes [227-229]. Differences between alcohol-soluble proteins of hard and soft endosperm of normal and quality protein maize show that the zein distribution influences kernel texture and hardness [230-232]. 

Explain the reason why quality protein or high-lysine maize is nutritionally superior compared to regular maize counterparts. Investigate how opaque-2 maize was transformed into quality protein maize. What other cereals have high-lysine types ... 

Anonymous. 1988. Quality Protein Maize. National Academy Press. Washington, D.C. 

Investigate the nutritional and nutraceutical properties of blue maize and quality protein maize tortillas. 

Amaya-Guerra, C., Sema-Saldivar, S.O., and Alanis-Guzman, M.G. 2006. Soybean fortification and enrichment of regular and quality protein maize tortillas affects brain development and maze performance of rats. Br. J. Nutr. 96 161-168. 

Serna-Saldivar, S.O., Herrera Macias, P., Amaya Guerra, C. A., Melesio Cuellar, J.L., Preciado Ortiz, R.E., Tenon Ibarra, A.D., and Vazquez Carrillo, G. 2008b. Evaluation of the lime-cooking and tortilla making properties of quality protein maize hybrids grown in Mexico. Plant Foods Human Nutr. 63(3) 119-125. 

Serna-Saldivar, S.O., Gomez, M.H., Islas-Rubio, A.R., Bockholt, A.J., and Rooney, L.W. 1992. The alkaline processing properties of quahty protein maize. Chapter 16 in Quality Protein Maize, E.T. Mertz (ed.). American Association of Cereal Chemists, SL Paul, MN. 

Sproule, A.M., Saldivar, S.O., Bockholt, A.J., Rooney, L.W., and Knabe, D.A. 1988. Nutritional evaluation of tortillas and tortilla chips from quality protein maize. Cereal Foods World. 33(2) 233-236. 

Sullivan, J.S., Knabe, D.A., Bockholt, A.J., and Gregg, E.J. 1989. Nutritional value of quality protein maize and food com for starter and grower pigs. J. Anim. Sci. 67 1285. 

Quality protein maize Genotypes that contain almost twice as much lysine and tryptophan than regular maizes and have better nutritional value. Quality protein maize has the opaque-2 gene that is combined with modifier genes that significantly improved the endosperm hardness and agronomic performance of the crop. 

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