Comparative nutritional advantage of quality protein maize (QPM) over normal maize (Zea mays L.) cultivars
2012
Gado, J.G. | Escobedo, E.G. | Badong, M.D. | Solivas, J.L., Philippines Univ. Los Baños, College, Laguna (Philippines). Inst. of Chemistry | Salazar, A.S., Philippines Univ. Los Baños, College, Laguna (Philippines). Inst. of Plant Breeding | Lacsamana, M.S. | Arreola, S.L.B. | Subularse, V.C., Philippines Univ. Los Baños, College, Laguna (Philippines). Inst. of Chemistry
Continued nutritional evaluation of different maize cultivars is essential to pinpoint desirable traits for breeding Quality Protein Maize. Analysis of protein, carbohydrates and beta carotene in yellow and white cultivars from QPM and normal maize were inducted. Proximate analysis was done to assess the overall nutritive quality of each group. Effect of grain processing and cooking on lysine, tryptophan, total carotenoids and carbohydrate contents were determined. All cultivars tested had comparable ash, crude fiber and total carbohydrate. Mineral content of the corn samples ranged from 1.16_1.65%, crude fiber 1.65_2.37%, and total carbohydrate, 72.8_81.3%. Normal maize had significantly higher crude protein (8.33%) than QPM (6.64%), attributable to the higher zein in the former. Yellow QPM have significantly highest lysine content (4.51 mg/g) but have comparable tryptophan levels with the rest. Generally, QPM have higher Amino Acid Score than normal maize. QPM cultivars have higher amylose content (low glycemic index) than normal cultivars though both groups have comparable starch content and amylose: amylopectin ratio. QPM and normal yellow maize cultivars have significantly higher total carotenoids compared to the QPM and normal white cultivars. QPM yellow cultivars' mean total carotenoid (20.14 ug/g) was significantly higher than normal yellow cultivars' (12.22 ug/g) content regardless of milling. Beta carotene was significantly higher in milled QPM yellow compared to normal yellow maize, regardless of cooking, but was undetected in the white cultivars. Grain processing decreased crude protein, increased carbohydrate and amylose content, but had no effect on lysine, tryptophan, total carotenoid and amylose: amylopectin ratio. Cooking did not affect protein quality of both groups of cultivars. The nutritive advantage of OPM over normal maize cultivars can help alleviate malnutrition especially in countries that highly depend on maize as staple.
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