Controlled Release Study on Bifidocin A from a Polyvinyl Alcohol/Chitosan Blend Particle-Based Biodegradable and Active Packaging Coupled with Mechanistic Assessment and Experimental Modeling

Abstract

On the basis of PVA-CS, which is incorporated with Bifidocin A, anti-microbial biodegradable films were prepared, characterized by their abilities to control the Bifidocin A’s total release rate into foods as needed for packaging of active foods. This study aimed to explore the anti-microbial effects and release kinetics of active substances in polyvinyl alcoholchitosan (PVA-CS) particle composite films added with Bifidocin A. Pseudomonas fluorescens was used as indicator bacteria to evaluate the anti-microbial activity of the films. Fick’s law, power law and negative exponential growth model were applied to further study the release kinetics of Bifidocin A. The results revealed that the composite films of PVA and CS had better mechanical properties and anti-microbial activity when the content of Bifidocin A was 50% with 1:1 PVA/CS, but it impairs the structure of the film, which can be resolved by including a suitable amount of grycerol. The anti-microbial was released faster at higher temperature and concentration of Bifidocin A, and the diffusion coeffcients increased significantlywith the increase of temperature and concentration. According to the thermodynamic parameters, the release of Bifidocin A was endothermic and spontaneous. High correlation factors (R2 > 0.99) were acquired by fitting the release data of the Bifidocin A with the negative exponential growth model. The potential of Bifidocin A to deliver from the films into the food analog appropriately at low temperatures favored the obtained active films to be applied on food packaging, especially suitable for refrigerated foods.

Flame-Retardant and Smoke-Suppression Properties of Bamboo Scrimber Coated with Hexagonal Boron Nitride

“…As illustrated in Figure 5c, compared to the untreated material, the peak smoke release rate of the 1% h-BN, 5% h-BN, and 10% h-BN flame-retardant-treated bamboo scrimber was delayed by 81.82%, 72.73%, and 54.55%, respectively, whereas, the peak smoke production rate was improved by 44.44%, 17.78%, and 55.56%, respectively. The smoke release was mainly caused by the PVA in the film-forming material burning when met with an open fire and releasing a large amount of smoke [25], but the h-BN could delay the smoke release of the bamboo scrimber.…”

“…Chitosan (CS) is a natural polysaccharide cellulose, widely found in the shells of insects and crustaceans and in the cell walls of fungi, also known as soluble chitin, which has become highly researched in recent years owing to its renewability, non-toxicity, and high biocompatibility [22], but the stronger intramolecular and intermolecular hydrogen bonding and the low crystallinity lead to the brittleness of CS membranes [23,24]. As a novel green material in recent years, polyvinyl alcohol (PVA) has good film-forming properties, chemical stability, solvent resistance, and strong adhesion [25]. Therefore, PVA and CS are commonly blended and adopted as film-forming substances [26,27] which not only have good film-forming properties but also possess a strong bonding ability.…”