Chemical treatment and characterization of soybean straw and soybean protein isolate/straw composite films

Abstract

This work investigated changes in the chemical composition and structure of soybean straw (SS) treated with alkali (NaOH 5% and 17.5%) and bleached with hydrogen peroxide (HO) or sodium hypochlorite (NaOCl). Removal of the amorphous constituents increased the degree of crystallinity and the content of cellulose fibers particularly after reaction with high concentrations of alkali. Treatment with NaOH 17.5% contributed to the allomorph transition from cellulose I to II regardless of the bleaching agent, but HO as bleaching agent promoted more effective delignification. This work also evaluated the potential use of treated and non-treated SS as reinforcement filler in soy protein isolate film (SPI). Films added with treated SS presented higher mechanical resistance, lower elongation at break, and lower solubility in water. Addition of non-treated SS did not affect the properties of the SPI film significantly. The low solubility and the reasonable water vapor permeability of the composite films make them suitable packaging materials for fresh fruit and vegetables.

Comparison Between Chitosan Nanoparticles and Cellulose Nanofibers as Reinforcement Fillers in Papaya Puree Films: Effects on Mechanical, Water Vapor Barrier, and Thermal Properties

“…When in suspension the Nf tend to aggregate with each other, primarily due to hydrogen bonds between hydroxyl groups, forming a packed network of entangled fibers. The isolated fibers as well as the cluster features are very close to those presented by the method in which the process of obtaining the fibers was followed .…”

The addition of sugarcane bagasse and asparagus peel enhances the properties of sweet potato starch foams

“…Because the starch/SB and the starch/AP foams had higher starch content than the fibers (SB or PA), the thermal stability of the starch/SB and starch/AP trays was mainly influenced by starch. SB and AP fibers degraded at 236°C and 216°C, respectively; this degradation temperature above 210°C referred to the thermo‐oxidative reaction of the main organic compounds (decomposition of lignin, hemicelluloses, and mainly cellulose) with overall mass loss around 70%. The mass loss observed for the starch/SB and starch/AP trays between 250°C and 400°C was due to degradation of cellulose by dehydration, depolymerization, or decomposition of glycosyl units, followed by formation of a carbonized residue and to degradation of saccharide rings .…”

“…The third additional event occurred between 360°C and 600°C, with a greater maximum peak almost at 478°C for the composite trays as compared with control tray (408°C), which indicates that the addition of SB or AP fibers increased the thermal stability of the sweet potato starch‐based foam tray. This stage is ascribed to the partially decomposed starch underwent oxidation, to generate solid residues such as ashes and inorganic materials (around 20% of the initial mass) and also may be ascribed to the degradation of lignin, which is present in the SB and PA fibers …”

Effect of Mussel‐Inspired Poly(Dopamine)‐Functionalized Carbon Nanotubes/Graphene Nanohybrids on Interfacial Adhesion of Soy Protein‐Based Nanocomposites

“…The absorption peak at 2,933 cm −1 was attributed to the stretching vibration of −CH 2 group [7]. In addition, the peaks at 1,403 and 1,045 cm −1 were ascribed to the C-H and C-O stretching vibrations, respectively [40]. The broad absorption band around 3286 cm −1 was attributed to the stretching vibrations of O-H and N-H groups [41].…”