Biodegradable Packaging Based on Poly(vinyl Alcohol) and Carboxymethyl Cellulose Films Incorporated with Ascorbic Acid for Food Packaging Applications.

Abstract

Petroleum-based plastics are used as packaging materials because of their low cost and high availability; however, continuous use of these nondegradable materials especially in the food industry has led to environmental pollution. The present study aimed to synthesize antibacterial and biodegradable films based on natural biopolymers carboxymethyl cellulose (CMC), poly(vinyl alcohol) (PVA), and ascorbic acid (AA) cross-linked in the presence of glutaraldehyde (GA). The films were synthesized in two different concentrations, 60PVA:40CMC:AA and 70PVA:30CMC:AA with a fixed amount of AA. Films with smooth texture and overall uniform thickness were obtained. Fourier transform infrared spectroscopy (FTIR) confirmed the cross-linking between the aldehyde group of GA and hydroxyl of PVA through detection of acetal and ether bridges. The synthesized films were thermally stable in the temperature range of 180-300 °C; however, 70PVA:30CMC:AA showed higher weight loss in this range as compared to the 60PVA:40CMC:AA film. Soil burial test demonstrated that the 60PVA:40CMC:AA film was more degradable (71% at day 15) as compared to the 70PVA:30CMC:AA film (65% at day 15). The films exhibited excellent antimicrobial activity against Gram-positive staphylococcus aureus(inhibition zone of 21 mm) and Gram-negative Escherichia coli (inhibition zone of 15 mm). In comparison, the 60PVA:40CMC:AA film showed better results in terms of high mechanical strength, uniform morphology, higher soil burial degradation, and lower water vapor transmission rate. Therefore, the prepared film could be used as a promising candidate in the food packaging industry.