Physical, antifungal, and biodegradable properties of cellulose nanocrystals and chitosan nanoparticles for food packaging application

Abstract

Nanocomposite polymeric films were prepared using the solvent casting method by incorporation cellulose nanocrystals (CNC), and chitosan nanoparticle (CNP) reinforced within the matrix of PVA (poly-vinyl alcohol). The CNC was prepared using by-products from the mango industry. Optimization studies on the films were based on their mechanical properties, viz: thickness, tensile strength, and elongation. Thermal characterizations were carried out by using the Differential Scanning Calorimetry (DSC) and TGA/DTA (Thermo-Gravimetric Analysis). TGA/DTA results revealed the films were thermostable at 450 °C for CNP, blend (CNC + CNP + PVA), and PVA films, whereas CNC film, was thermostable up to 430 °C. The antifungal activity of the films was investigated against postharvest pathogens, such as Colletotrichum gloeosporioides and Lasiodiplodia theobromae, inhibition against C. gloeosporioides was 70% for CNC films. In contrast, the PVA film showed better inhibition against L. theobromae (51%). The biodegradability of the films was tested in wet and dry soil conditions. The highest percentage of biodegradation recorded for the blended film, which was 88% for dry soil and 54% for CNP films under wet soil conditions. The mango fruits were packaged in the polymeric films prepared, and the shelf life studies were conducted based on the physiological loss of weight (PLW) over a storage period of 20 days. Mangoes packed with CNC films, were free from attacks by mango-associated postharvest decay, during the storage period. These studies suggested that CNC films can be used for the packaging of fresh fruits.