Synthesis and Characterization of Nanochitosan-Based Smart Film as Future Food Packaging Material

Recent developments of materials for food packaging have been attempted to utilize biodegradable materials such as nanochitosan. The composite film of nanochitosan can be synthesized with various suitable materials. In this particular study, nanochitosan was paired with polyethylene glycol (PEG) because PEG has the ability to strengthen nanochitosan film. This study aims to determine the characteristics of nanochitosan and nanochitosan-PEG in an effort to develop smart edible film designed to monitor food freshness. Several stages had been conducted, it all began with the synthesis of nanochitosan and nanochitosan-PEG. The samples of nanochitosan-PEG were conditioned consecutively with various PEG concentrations of 1, 1.5 and 2 %. Nanochitosan and nanochitosan-PEG were characterized by using Fourier Transform Infrared (FTIR), Particle Size Analyzer (PSA), and Structural Equation Modeling (SEM) spectrophotometer, while stability was tested with a UV-Vis spectrophotometer. The results of FTIR interpretation showed the functional groups like -OH, -NH, C=O carboxylate, P=O, and C-O-C. These functional groups featured a fairly sharp absorption peak implying the characteristic of PEG. The PSA test revealed that the nanochitosan-PEG 2 % obtained the smallest particle size. The treatment of time variations was required to react the nanochitosan-PEG 2 % with the ionic gelation method within 30, 60, and 120 min. After a 2-hour reaction, the smallest size particle reached 9.78 nm with a polydispersity index value of 0.021. The morphology of samples in the SEM test showed non-uniform spherical aggregates. The film yield proceeded to use on chicken meat for indicating the meat’s freshness. It took 48 h signifying a decline of protein content from 18.30 to 15.86 % as the film experienced a color change from purple to green according to the pH level of the decaying meat. This suggests that the film is smart and reliable to monitor food freshness through visual pH changes. HIGHLIGHTS The potential of polyethylene glycol (PEG) and nanochitosan composites as a smart food packaging is a novelty of this research. Until now, most of crosslinkers to nanochitosan only uses citric acid and acetic acid. As the result, the citric acid-crosslinked chitosan (CsC) has rigid and brittle film which means it’s prone to cracking. To overcome this issue, the addition of PEG is important to reduce the brittleness of the film because PEG acts as a binder. This research suggests that smart food packaging can be obtained from PEG-chitosan with the anthocyanin extract that functions as a food preservation detector. This research introduces the novel potential of PEG and nanochitosan composites as smart food packaging materials, addressing the limitations of traditional crosslinkers like citric acid and acetic acid. While citric acid-crosslinked nanochitosan film tends to be rigid, brittle, and prone to cracking, PEG functions as a binder in smart packaging, enhancing flexibility and reducing brittleness. The study suggests that PEG-chitosan composites combined with anthocyanin extract can serve as a food preservation detector, adding an intelligent detection feature to smart packaging applications. GRAPHICAL ABSTRACT