PVA–nano cellulose active packaging films with clay nano particles and fennel seed essential oil for enhanced thermal, barrier, antimicrobial, antioxidant and biodegradation properties to improve the shelf life of tofu †

Abstract

In this study, Box Badam Pod Nano Cellulose Particles (BBNCPs) were prepared using a combination of physiochemical treatments. After each treatment, the removal of organic constituents from the raw material, other than cellulose, was confirmed by FTIR analysis. XRD analysis of BBNCPs showed a crystallinity of 88%. The morphological study of BBNCPs was conducted using SEM, TEM, and AFM. Their size was confirmed to be in the range of 4–8 nm. Then, a BBNCP-reinforced novel active packaging film was fabricated for the packaging of tofu. The casting solution of the optimized film contained 8% polyvinyl alcohol (PVA), 2.25 ml fennel seed essential oil, 1.75% BBNCP, and 6% montmorillonite nano clay. The active packaging material exhibited superior tensile strength (7 ± 0.01 N mm⁻²), thermal properties (complete degradation at 800 °C), oxygen transfer rate (2.6 cm³ per m² per day), antioxidant activity (58.12 ± 0.08%), antimicrobial properties (against E. coli and Shigella flexneri) and biodegradation (complete degradation within 50 days) compared to neat PVA. After packing, the analysis of physiochemical properties, as well as microbial and sensory analysis of tofu was performed at regular intervals during storage (4 °C). A statistically significant difference (P < 0.05) was found for the quality parameters of tofu when packed in a nanocomposite film compared to when packed in a neat PVA film. Hence, BBNCP-reinforced active packaging is suggested to extend the shelf life of tofu.