Modified Chitosan-Based Coating/Packaging Composites with Enhanced Antibacterial, Antioxidant, and UV-Resistant Properties for Fresh Food Preservation.

Chitosan-based biomass packaging materials are a promising material for food preservation, but their limited solubility, antioxidant capacity, UV resistance, and mechanical properties severely restrict their application. In this study, we developed a novel chitosan-based coating/packaging composite (QCTO) using quaternary ammonium salt and tannic acid (TA)-modified chitosan (QCS-TA) and oxidized chitosan (OCS). The introduction of quaternary ammonium salt and TA effectively improves the water solubility and antibacterial, antioxidant, and UV-resistant properties of chitosan. The Schiff-base bond formed between OCS and QCS-TA, along with the TA-mediated multiple interactions, conferred the prepared composite film with good mechanical properties (69.9 MPa tensile strength) and gas barrier performance to water (14.3 g·h-1·m-2) and oxygen (3.5 g·mm·m-2·h-1). Meanwhile, the prepared QCTO composites demonstrate excellent biocompatibility and safety and are applied as coatings for strawberries and bananas as well as packaging films for mushrooms. These preservation experiments demonstrated that the prepared composites are able to effectively reduce weight loss, prevent microbial growth, maintain color, and significantly prolong the shelf life of fresh products (bananas, strawberries, and mushrooms extended shelf life by 6, 5, and 6 days, respectively). Therefore, the developed QCTO coating/packaging film shows great potential for applications in the field of food preservation and packaging.

Hyaluronic acid-based multifunctional bio-active coating integrated with cinnamaldehyde/hydroxypropyl-ß-cyclodextrin inclusion complex for fruit preservation.

Natural preservatives such as cinnamaldehyde (CIN) are garnering increasing interest to replace their synthetic counterparts in maintaining fruit freshness and safety. However, their long-term effectiveness and widespread application have been greatly limited due to high volatility and potent aroma. To address these challenges, we developed a viable and simple strategy to prepare a multifunctional active coating for fruit preservation by incorporating host-guest inclusion complex of CIN and 2-hydroxypropyl-ß-cyclodextrin (HP-ß-CD) CIN@HP-ß-CD into hyaluronic acid (HA), a natural polysaccharide with exceptional film-forming properties. The as-prepared HA/CIN@HP-ß-CD coatings exhibited universal surface affinity, excellent antimicrobial performance, and satisfactory antioxidant properties with no potential toxicity. Release kinetic studies have demonstrated that CIN in the coating is continuously and slowly released. Furthermore, freshness preservation experiments on bananas and fresh-cut apples demonstrated that the developed coating is effective in preserving the color of fruit, decreasing the weight loss rate, preventing the microorganism's growth, and significantly extending the period of freshness, exhibiting the potential for application in fruit preservation.

Development of mussel-inspired chitosan-derived edible coating for fruit preservation.

Fruit rotting at the postharvest stage severely limits their marketing supply chains and shelf-life. Thus, developing a green and cost-effective approach to extend the shelf-life of perishable foods is highly desired. In this study, inspired by the mussel-adhesion strategy, a multifunctional fruit coating material has been developed using a quaternized catechol-functionalized chitosan (CQ-CS) grafted with 2, 3-epoxypropyl trimethyl ammonium chloride and 3, 4-dihydroxy benzaldehyde. The as-prepared CQ-CS coating exhibited excellent mechanical properties, universal surface adhesion abilities, antimicrobial and antioxidant capacities without any potential toxicity effects. Using strawberry and banana as model fruits, we showed that the CQ-CS coating could effectively maintain the fruit's firmness and color, decrease the weight loss rate, and prevent microbial growth, thus finally extending their shelf- life when compared to uncoated samples, indicating the universal application of the as-prepared CQ-CS coating. These findings demonstrated that this novel conformal coating of CQ-CS has great potential for fruit preservation in the food industry.