Caracterização de agroresíduos oriundos da cadeia de processamento do gengibre: composição, estrutura, morfologia e propriedades témicas

Abstract

This study aimed to characterize ginger (Zingiber officinale) residues containing lignocellulosic material to aid in the future development of their applications in sustainable materials. These residues were obtained from the extraction of ginger starch from the rhizome, called extracted bagasse (BGext), and the industrial residue (BGind) provided by a food company specializing in ginger-based products. The main objective was to determine the physical-chemical properties of these agro-residues and verify their potential for the future production of new materials acting as a source of filler for polymer matrices in (nano) composites. Few studies in the literature address this type of material for this purpose. Characterizations (qualitative and quantitative) of its properties were carried out, which included: macroscopic composition of BGind, composition of ginger fiber (TAPPI standards), structure of bagasse (by Fourier Transform Infrared Spectroscopy - FTIR and X-ray Diffraction - XRD), morphology (by Scanning Electron Microscopy - SEM) and thermal stability in an inert atmosphere (by Thermogravimetric Analysis - TG). The results indicated that BGext is a material of greater purity in terms of composition, which is basically composed of lignocellulosic fibers and little plant cellular material. Consequently, BGext presented greater crystallinity and thermal stability in relation to BGind. In the latter, a significant amount of residual starch (14.42 ± 1.35%) and husks (29.03 ± 1.20%) were found, and the fiber content was 28.80 ± 1.30%. Regarding ginger fiber, it presented significant amounts of hemicelluloses (29.97 ± 1.26%) and lignins (28.23 ± 2.39%), while the cellulose content was 48.41 ± 2.03%. Therefore, the use of BGind is favored when the final objectives are the development of materials such as composites or blends of polymeric matrices, such as starch, due to the presence of residual starch in this material that can also be used as a matrix. BGext, being cleaner, favors its use for obtaining cellulosic structures on a nanoscale, since fewer additional physical and chemical treatment processes for cellulose purification will be necessary, making its use more indicated for the development of polymeric nanocomposites. In this way, this study contributed to the understanding of the structure and properties of waste from ginger processing, directing its potential applications, establishing a basis for future research and development in the area of materials derived from biomass, also covering concepts of circular economy and sustainability.