Development of microparticles from wheat glutenins by electrospray and potential application as controlled-release fertilizers

Development of microparticles based on natural polymers has been of interest for researchers due to their applications, such as release systems. Currently, one of the problems presented by agriculture worldwide is the loss of fertilizers, i.e., urea, causing environmental pollution and high costs. The aim of this work was to develop microparticles of wheat glutenins by means of electrospray technique, with potential application as a urea controlled-release system in agricultural soils. The microparticles of wheat glutenins were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). In addition, a release kinetic test was performed to evaluate the possible behaviour of wheat-glutenin microparticles in agricultural soils with pH 4, 7 and 10, using buffers as the release medium. TGA indicated that microparticle stability was $${>}100{^\circ }\hbox {C}$$ , while FT-IR demonstrated the existence of physical interactions between urea and wheat glutenins. The kinetic tests showed the possible behaviour of the controlled-release fertilizer at pH 4, 7 and 10; rapid release at acidic pH and a decrease in release time at basic pH. With these results, we can conclude that the urea-charged wheat-glutenin microparticles can function as a controlled-release fertilizer in agricultural soils.