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.