RESUMEN
The main aim of the present study was to characterize banana starch films reinforced with nanoparticles from plantain rachis. Nanoparticles were obtained by acid hydrolysis and sonication, exhibiting a mean hydraulic diameter of about 60 nm. Scanning electron microscopy micrographs showed that the nanoparticle thickness ranged between 9.8 and 22.3 nm. The thermal gravimetric analysis showed that nanoparticles are thermally stable for temperatures up to 340 °C. Films were made for different fractions of nanoparticles (0.0, 1.75, 2.5, and 4.0%) relative to total solids, and glycerol was used as a plasticizer. The influence of the addition of nanoparticles to starch films on the morphology, water vapor permeability (WVP), and mechanical properties of the nanocomposites films was explored. Cellulose nanoparticles reduced the WVP, and increased the tensile strength and flexibility of the starch films. FTIR analysis of films was used to show that nanoparticles improved the molecular organization of starch chains. It was proposed that nanoparticles acted as a crosslinked for starch chains via hydrogen bonding effects.
Asunto(s)
Celulosa/química , Membranas Artificiales , Musa/química , Nanopartículas/química , Plantago/química , Almidón/química , Permeabilidad , Resistencia a la TracciónRESUMEN
Pure potato starch has been modified by high-energy-ball-milling as a function of energy supplied, aiming to obtain products for different possibilities of industrial application. Burgios's equation has been used to calculate the energy supplied. The effect of the milling has been followed by a characterization of the starch morphology, crystallinity, solubility, swelling, retrogradation, viscosity, apparent viscosity, functional groups, and reducing sugar concentration. The high-energy-ball-milling not only changes the physical properties but also induces the mechanolysis of potato starch, breaking the glycosidic linkages of the starch molecules. A representation of the possible mechanism of starch mechanolysis is proposed. Three stages of the transformation of potato starch through high-energy ball-milling can be identified. Each of these stages generates starch with properties that can be used in different industrial applications.