[Evaluation of the flour and starch from white and purple varieties of mapuey (Dioscorea trifida)].

Mapuey (Dioscorea trifida), is a tropical America tuber, which is appreciated for its taste and fine texture. It has not been fully cultivated in Venezuela, even though products like its flour and starch could replace conventional used products. In this work physical and chemical characteristic of flours from mapuey (varieties white and purple), were assessed, as well as some of their micronutrients. Physical, physicochemical and rheological properties, and chemical composition of isolated starches were also evaluated. Flours were obtained by a drying process and starches by aqueous extraction. Chemical analysis was performed following standard methodologies. The flour yield of purple mapuey was the highest, as was its protein content. The minerals content, showed significant differences between both varieties, presenting purple variety a higher content. Isolated starches showed high purity, this was corroborated by the scanning electron microscopy which showed irregular shaped granules (oval and elongated), with truncated end and smooth surfaces. Purple mapuey granules were smaller. Both varieties exhibited a B type diffraction pattern. The greater swelling power and water absorption capacity was presented by white mapuey, while the highest solubility was shown by the purple one. The white mapuey had maximum viscosity, as well as the highest value of breakdown, suggesting more fragile granules. Setback was lower in the white mapuey, suggesting lower tendency to retrogradation. The purple mapuey although, it showed a higher amylose content, presented lower consistency, even though the difference was not relevant.