Application of Chitosan Film as an Active Food Packaging Based on Citric Acid and Sodium-Tripolyphosphate as Crosslinker

Chitosan film is an environmentally friendly biopolymer and has antimicrobial properties, making it suitable for application as active packaging. Naturally, chitosan in acetic acid can be made into a film, but its mechanical strength is low. Therefore, in this study, a chitosan film has been made by adding crosslinking reagents, citric acid and sodium tripolyphosphate (STPP). Both crosslinking reagents have been widely studied as chitosan crosslinkers, but their application as active packaging is a new innovation. In this study, a chitosan film has been made using the solution casting method: ۱% chitosan in ۲% acetic acid with crosslinking from citric acid and STPP, and glycerol as a plasticizer. The chitosan-citric acid film has been made with a composition of ۸۰% chitosan, ۱۶% citric acid, and ۴% glycerol, while for the chitosan-STPP film, comprises ۷۵% chitosan, ۲۲% STPP, and ۳% glycerol. Film characterization includes FTIR spectrum, mechanical properties, optical properties, water vapor barrier, and antibacterial activity. The results showed that citric acid is better than STPP as a crosslinker, indicated by the properties of chitosan-citrate films being superior to those of chitosan-STPP. The properties of chitosan-citrate films are tensile strength ۴۰.۹±۱.۰۴ N/mm۲, elongation at break ۱۵±۱.۰۶%, haze ۶.۵۶۸±۰.۳۲%, WVTR ۱۰۰.۸±۱.۹۲ g m۲. On Day ۱, antibacterial activity against E. coli ۴.۲۵ log CFU/mL and S. aureus ۴.۱۱ log CFU/mL. Chitosan films have been applied as cherry tomato packaging, allowing tomatoes to remain fresh for up to ten days.

کلیدواژه ها:

Active packaging ، Chitosan films ، Crosslinker ، Citric acid ، Sodium tripolyphosphate