Agricultural waste-derived cellulose nanocrystals for sustainable active food packaging applications

Sustainable, biodegradable active food packaging has been considered a potential candidate to solve problems associated with petroleum-derived packaging materials and food waste generation. Accordingly, the latest technology using active food packaging based on cellulose nanocrystal (CNC) reinforced biocomposite films is one of the packaging solutions to prevent food degradation from mechanical, chemical and microbial damage. Among the available bionanomaterials, CNC is a potential candidate for developing biocomposite-based food packaging for their non-toxicity, abundance, biodegradability, biocompatibility, bio-based, crystalline, renewable resource origin, and surface chemistry. In this review, we discussed various fabrication techniques of CNC including acid hydrolysis, enzymatic hydrolysis, subcritical water hydrolysis, oxidative digestion, ammonium persulfate, and TEMPO oxidation for CNC extraction. Various methods are used to characterize the physical, chemical, and surface properties of CNC, such as X-ray photoelectron spectroscopy, X-ray diffraction spectra, elemental analysis, morphological analysis, and Fourier transform infrared spectroscopy. Various processing techniques for CNC-based packaging include solution casting, blown film, and melt extrusion. Using CNC as reinforcement materials influences the packaging properties such as barrier (gas, water vapor, UV light), mechanical, thermal, optical, and functional properties. The review also discusses the use of CNC-based nanocomposites for active packaging applications.