Thermoplastic Starch Biocomposite Films Reinforced with Nanocellulose from Agave tequilana Weber var. Azul Bagasse

In this work, cellulose nanocrystals (CNCs), bleached cellulose nanofibers (bCNFs), and unbleached cellulose nanofibers (ubCNFs) isolated by acid hydrolysis from Agave tequilana Weber var. Azul bagasse, an agro-waste from the tequila industry, were used as reinforcements in a thermoplastic starch matrix to obtain environmentally friendly materials that can substitute contaminant polymers. A robust characterization of starting materials and biocomposites was carried out. Biocomposite mechanical, thermal, and antibacterial properties were evaluated, as well as color, crystallinity, morphology, rugosity, lateral texture, electrical conductivity, chemical identity, solubility, and water vapor permeability. Pulp fibers and nanocelluloses were analyzed via SEM, TEM, and AFM. The water vapor permeability (WVP) decreased by up to 20.69% with the presence of CNCs. The solubility decreases with the presence of CNFs and CNCs. The addition of CNCs and CNFs increased the tensile strength and Young's modulus and decreased the elongation at break. Biocomposites prepared with ubCNF showed the best tensile mechanical properties due to a better adhesion with the matrix. Images of bCNF-based biocomposites demonstrated that bCNFs are good reinforcing agents as the fibers were dispersed within the starch film and embedded within the matrix. Roughness increased with CNF content and decreased with CNC content. Films with CNCs did not show bacterial growth for Staphylococcus aureus and Escherichia coli. This study offers a new theoretical basis since it demonstrates that different proportions of bleached or unbleached nanofibers and nanocrystals can improve the properties of starch films.

Identificación de propiedades presentes en jugo de Opuntia megacantha Salm-Dyck importantes para la producción de biopolímeros

Con el objetivo de identificar las propiedades químicas y los antioxidantes de interés en la industria de los biopolímeros se realizó la caracterización química del jugo de cuatro variantes de cladodios de Opuntia megacantha; las variantes presentan dos grados de madurez (tiernos y maduros) y dos manejos diferentes durante su desarrollo (silvestres y cultivados). El grado de madurez de los cladodios fue estadísticamente significativo (p ≤ 0.05), el jugo de los cladodios maduros presentó mayor cantidad de fibra cruda y material libre de nitrógeno, el jugo de cladodios tiernos contiene mayor cantidad de proteína, extracto etéreo y cenizas. No existió diferencia estadística significativa (p = 0.6917), en el contenido de los fenoles en las cuatro variantes se obtuvieron concentraciones entre 165.6 y 176.6 mg GAE/mL; (2.18 y 3.61 mg GAE/g en peso seco). Los jugos de los cladodios maduros contienen mayor cantidad de los diferentes azúcares cuantificados (p ≤ 0.05). Se prepararon películas de biopolímero utilizando jugo clarificado de cladodios silvestres tiernos para determinar su resistencia a la tensión con un resultado de 1.42 MPa, módulo de Young de 1.77 MPa y elongación a la rotura de 124.16%; se concluye que los jugos caracterizados en este trabajo pueden ofrecer una alternativa viable a los polímeros derivados del petróleo.

Nutritional and Bioactive Compounds in Mexican Lupin Beans Species: A Mini-Review

As a source of bioactive compounds, species of the genus Lupinus are interesting legumes from a nutritional point of view. Although wild species are abundant and represent a potential source of nutrients and biologically active compounds, most research has focused on domesticated and semi-domesticated species, such as Lupinus angustifolius, Lupinus albus, Lupinus luteus, and Lupinus mutabilis. Therefore, in this review, we focus on recent research conducted on the wild Lupinus species of Mexico. The nutritional content of these species is characterized (similar to those of the domesticated species), including proteins (isolates), lipids, minerals, dietary fiber, and bioactive compounds, such as oligosaccharides, flavonoids, and alkaloids.