RESUMO
The aim of this study was to obtain cellulose and cellulose nanoparticles (CNP) from garlic and agave wastes, as well as elucidating its structure at different scales using microscopy and spectroscopy techniques. Cellulose is isolated by using a sequential extractive process and monitored by CLSM and SEM, while CNP are produced in a high-energy planetary mill. FTIR and XRD confirmed the presence of cellulose type I and CI and Dhkl was used to evaluate the size of CNP. The corresponding crystalline structure, d-spacing and angles obtained from crystalline regions of CNP were estimated by TEM and computational simulation. It is shown that the triclinic phase is predominant in G, and a monoclinic conformation in CNP for A. The novelty of this contribution is to demonstrate that the crystalline structure of CNP, extracted from different agro-food wastes, depends on its initial microstructural arrangement (laminar or fibrillar).
RESUMO
The cuajilote (Parmentiera edulis D.C.) tree produces fibrous fruits with a high content of lignocellulosic compounds. However, this fruit and their fibers have been scarcely studied. For this reason, an integral study of their cellular architecture, physicochemical, micromechanical, and structural properties in two maturity stages were carried out. Physicochemical tests, light, confocal and electron microscopy, microindentation, and X-ray diffraction were used for the characterization of fruit and their fibers. Chemical analysis showed that the unripe fruits have the highest cellulose content (42.17%), but in ripe fruit the cellulose content decreases (32.76%) while lignin content increases from 35.26 to 40.79%, caused by the lignification of the sclerenchyma fibers. Microstructural and micromechanical studies in the different regions of the fruit provided relevant information about its cellular architecture, distribution of lignocellulosic compounds and its role in the micromechanical properties of their fibers. The thickening cell wall of sclerenchyma fibers was caused by the cellular lignification of the ripe fruits. According to the physicochemical and structural studies, cuajilote fibers are comparable to other fibers obtained from crops rich in lignocellulosic compounds. The current study provided new knowledge about the cellular architecture of fruit and criteria for selecting the ripening stage adequate for the extraction of cellulose or lignin. Furthermore, information regarding the micromechanical properties of their fibers and which structural arrangement could be more convenient for mechanical reinforcement of biodegradable materials was obtained.
