Fabrication and characterization of active nanocomposite films loaded with cellulose nanocrystals stabilized Pickering emulsion of clove bud oil.

There is a tremendous increase in the development of alternative food packaging materials which are functional, environment-friendly, and can improve the shelf-life of food products. One such possible approach is to develop biopolymer-based active films loaded with antimicrobial essential oils. In the present study, pearl millet starch (PMS) films reinforced with kudzu cellulose nanocrystals (CNCs) stabilized Pickering emulsions of clove bud oil (CBO) were developed as active and sustainable packaging material. Active nanocomposite films were prepared by blending PMS with Pickering emulsions of CBO at 0.5, 1, 1.5, and 2 wt% conc. Using the solution casting method. Overall, active nanocomposite films displayed improved thermal, mechanical, and water barrier properties, with an optimum CBO-Pickering emulsion concentration of 1.5 %. CBO and PMS films showed strong chemical interactions, which significantly improved the mechanical resistance of the film. Further, SEM showed the appearance of micro-porous holes in the films because of partial evaporation on the cryo-fractured surface due to the vacuum condition. In addition, films exhibited antimicrobial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with a rate response from increasing CBO Pickering emulsion concentration from 0.5 to 2 %. E. coli and S. aureus exhibited an inhibition zone ranging from 10.5 to 2.15 mm and 11.2 to 22.1 mm. This study suggests that PMS starch and kudzu CNCs-based active nanocomposite films loaded with CBO-Pickering emulsions have good potential to develop active and sustainable packaging materials.

Pearl millet starch-based nanocomposite films reinforced with Kudzu cellulose nanocrystals and essential oil: Effect on functionality and biodegradability.

This paper documents the preparation of three biopolymer films: 1) pearl millet starch (PMS) films, 2) PMS films reinforced with cellulose nanocrystals (CNCs), and 3) PMS films reinforced with CNCs stabilized Pickering emulsion of clove bud oil (CBO) and a comparison of their mechanical and water barrier properties and biodegradation behavior in soil. Reinforcing PMS films with Kudzu CNCs/CBO significantly increased tensile strength (from 3.9 to 16.7 MPa) and Young's modulus (from 90 to 376 MPa) but reduced the elongation (54.2 to 30 %) at the break of nanocomposite films. Also, the water vapor permeability of nanocomposite films decreased (from 9.60 to 7.25 × 10-10gm-1s- 1Pa-1) with the incorporation of Kudzu CNCs/CBO. The fastest biodegradation was observed for PMS films (98% in 15 days), followed by PMS films reinforced with Kudzu CNCs (96% in 18 days), followed by PMS films reinforced with Kudzu CNCs stabilized Pickering emulsions (94% in 21 days). The morphological analysis found hyphae-like structure formation due to microbial action, which increased over time. In general, all three biopolymer films showed good biodegradation behavior, and they all degraded between 15 and 21 days, suggesting that starch-based films reinforced with Kudzu CNCs provide a technique for the production of biodegradable packaging material.

Starch-based bio-nanocomposites films reinforced with cellulosic nanocrystals extracted from Kudzu (Pueraria montana) vine.

In the current study, starch-based active nanocomposite films reinforced with cellulosic nanocrystals (CNCs) of Kudzu were developed as an alternative option to existing biodegradable plastic packaging. Firstly, Kudzu CNCs were prepared by subjecting Kudzu fibers to the processes such as depolymerization followed by bleaching, acid hydrolysis, and mechanical dispersion. Further, nanocomposite films were formulated by blending pearl millet starch (PMS) and glycerol (30%) with different Kudzu CNCs compositions (0-7 wt%) using the solution casting process. The prepared PMS/Kudzu CNCs nanocomposite films were analyzed for their morphological (SEM and TEM), thermal (TGA and DSC), structural (FTIR), mechanical (tensile strength (TS), elongation at break and young modulus), and water barrier properties. The PMS/Kudzu CNCs films possessed improved crystallinity, heat and moisture-barrier properties, TS, and young-modulus after reinforcement. The optimum reinforcer concentration of CNCs was 5%. The Kudzu CNCs reinforced starch film offers a promising candidate for developing biodegradable films.