Synthesis of lignin from waste leaves and its potential application for bread packaging: A waste valorization approach

Excellent facile fabrication of PVA and lignin nanoparticles from wheat straw after novel DES-THF pretreatment

The utilization of environmental friendly and renewable materials has received increasing attention recently. Lignin nanospheres (LNPs) prepared from recovered lignin and residual lignin after DESs and DESs-THF pretreatment were obtained by self-assembly in the present research. Then, films were prepared by incorporating them into polyvinyl alcohol (PVA) solution. The properties of various films were characterized and compared. Results showed that as the LNPs content increased, the UV blocking capacity of the films was gradually enhanced than PVA film. The DES-THF films showed better antioxidant properties up to 69 % due to higher phenolic hydroxyl content. The hydrophobicity of films incorporated with DESs-THF pretreated lignin was consistently better than that of DES pretreated. DES-THF-M films showed a higher Tmax than that of DES-M films, resulting in better thermal stability. Moreover, DES-THF-L films are lighter in color due to a lower degree of condensation, which is favorable to subsequent applications. The incorporation of LNPs improved mechanical and antioxidant properties, thermal stability, and UV shielding ability of PVA films, especially lignin after DES-THF pretreatment. In conclusion, the prepared PVA/LNPs composite films possessed good functional properties that make them potential for packaging materials.

Innovative Biobased and Sustainable Polymer Packaging Solutions for Extending Bread Shelf Life: A Review

Sustainable packaging has been steadily gaining prominence within the food industry, with biobased materials emerging as a promising substitute for conventional petroleum-derived plastics. This review is dedicated to the examination of innovative biobased materials in the context of bread packaging. It aims to furnish a comprehensive survey of recent discoveries, fundamental properties, and potential applications. Commencing with an examination of the challenges posed by various bread types and the imperative of extending shelf life, the review underscores the beneficial role of biopolymers as internal coatings or external layers in preserving product freshness while upholding structural integrity. Furthermore, the introduction of biocomposites, resulting from the amalgamation of biopolymers with active biomolecules, fortifies barrier properties, thus shielding bread from moisture, oxygen, and external influences. The review also addresses the associated challenges and opportunities in utilizing biobased materials for bread packaging, accentuating the ongoing requirement for research and innovation to create advanced materials that ensure product integrity while diminishing the environmental footprint.

Vanillin Cross-Linked Chitosan Film with Controlled Release of Green Tea Polyphenols for Active Food Packaging

We report a novel cross-linked chitosan composite film containing vanillin, glycerol, and green tea extract. The effects of vanillin-mediated cross-linking and the incorporation of antimicrobial green tea polyphenols were investigated. The cross-linking effect, confirmed by Fourier transform infrared (FTIR) analysis, increased the tensile strength of the biopolymer film to 20.9 ± 3 MPa. The release kinetics of polyphenols from the chitosan-vanillin matrix was studied, and we reported an initial burst release (8 h) followed by controlled release (8 to 400 h). It was found that both vanillin and green tea polyphenols were successful inhibitors of foodborne bacteria, with a minimum inhibitory concentration of the tea polyphenols determined as 0.15 mg/mL (Staphylococcus aureus). These active components also displayed strong antioxidant capacities, with polyphenols quenching >80% of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals at all concentrations tested. Degradation results revealed that there was a significant (>85%) mass loss of all samples after being buried in compost for 12 weeks. The biopolymeric films, prepared by solvent casting methods, adhere to green chemistry and waste valorization principles. The one-pot recipe reported may also be applied to other cross-linkers and active compounds with similar chemical functionalities. Based on the obtained results, the presented material provides a promising starting point for the development of a degradable active packaging material.