Efecto de la incorporación de sales en la capacidad superabsorbente de matrices bioplásticas de proteína de soja

Abstract

Recent studies have proposed the use of soy protein-based bioplastic matrices for the controlled incorporation of micronutrients into crops, mitigating the excessive use of fertilizers in horticulture. However, micronutrient incorporation reduces the superabsorbent capacity of these bioplastic matrices, limiting their use as a source of water for crops. The aim of this study was to evaluate the effects of different factors on the loss of water superabsorbent capacity. To this end, we analyzed: (1) the effect of pH, using zinc sulfate monohydrate (ZnSO4·H2O) as a reference and varying the matrix systems towards acid and base, (2) the complex character of the salt, comparing the resonant effect caused by ZnSO4·H2O with that of zinc chloride (ZnCl2) and (3) the ionic strength, comparing the ZnSO4·H2O system with another with zinc chelated with 2,2',2'',2'''-(ethene-1,2-diydinitrile)tetraacetic acid (Zn-EDTA), which is an insoluble salt, were evaluated. Thus, the mechanical (tensile and flexural), microstructural and functional (water uptake capacity and micronutrient incorporation) properties of the different systems were evaluated. The results of this study help to understand the effects of the variation in these three factors on the loss of the superabsorbent capacity of soy-protein bioplastic matrices with incorporated micronutrients.