Stabilization time of chemical attributes and nutritional quality of manipueira for biofertilization

Abstract

Manioc flour and gum (starch) have a cultural value for Amazonians. The processing of cassava roots releases manipueira, a liquid waste with a high polluting potential, due to its high levels of hydrocyanic acid. The large volumes of manipueira produced in this sector require safe disposal, whether for cooking (tucupi, flour), drinking or agronomic purposes. The aim of this study was to evaluate the stabilization time of chemical attributes and the nutritional quality of manipueira. For this study, cassava roots of the Amazonas cultivar (bitter or wild) harvested 12 months after the manioc was grown, were processed to extract the manipueira, which was stored and sampled at 0; 2; 5; 8; 11; 18; 25; 32; 46; 62 and 92 days. The variables evaluated were: pH and total cyanide content. Nutrients (N, P, K, Ca, Mg and S) were assessed at 0, 47, 62 and 92 days after storage (DAA). The pH stabilized at 10 DAA, varying between 3.8 and 4.0. The total cyanide content stabilized at 62 DAA, containing 410 mg L-1. The macronutrient contents did not vary with storage time, with the following decreasing order of concentration: K > N > P > Mg > Ca > S, corresponding to the contents: 7.49; 1.25; 1.06; 0.68; 0.41 and 0.18 g-1, respectively.