Preparation, characterization and tomato preservation applications of gelatin-polyvinyl alcohol composite films with temperature and pH responsive properties
Mengge Zhai, Jie Sheng, Ruxin Zhang, Mengkai Cao, Ziyi Chen, Yishan Song
Abstract
In recent years, the construction of responsive nano-antimicrobial films has been a hot topic in reducing microbial resistance and food preservation. However, the non-degradable and mono-responsive nature of most films limits their application. In this study, silica nanoparticles were modified by imine bonding and poly-N-isopropyl acrylamide (PNIPAM), and citral (CIT) was added as an active substance to construct temperature- and pH-responsive nanoparticles (HMSS-NH 2 -CIT-PNIPAM, abbreviated as HNCP). It was then added to a gelatin (GEL)/polyvinyl alcohol (PVA) film to produce a degradable GP/HNCP composite film . The films were also evaluated for their physical properties, release characteristics, and tomato preservation. The tensile strength of the film was increased by 39.26 % as compared to the control. And the films had a good elongation (253.0 ± 4.53 %). The TGA results showed that the loading of CIT in HNCP was 42 % and the composite membrane could sustain the release for 120 + h under combined pH and temperature (pH 5.8/37 °C) stimulation. In addition, in tomato preservation experiments, tomatoes treated with GP7 composite film extended shelf life by 3–4 days compared with the control group. The biodegradability and good cytocompatibility of the composite membrane were demonstrated by degradation rate and MTT experiments. Therefore, GEL/PVA/HNCP smart response composite film is a smart antimicrobial packaging material with wide application prospects.