Eco-friendly chitosan-based composite film with anti-dissolution capacity as active packaging for fruit preservation

Natural polysaccharide-based active packaging has attracted increasing attention in food preservation due to their environment-friendly and biodegradability. However, the water solubility of hydrophilic biopolymer caused the uncontrolled release of active factor and poor preservation effect in high moisture packaging microenvironments. Herein, a sort of chitosan (CS)/cellulose nanofiber (CNF)/vanillin (VA)-calcium (Ca) (CS-CNF/ VA-Ca) active film with well anti-dissolution capacity was successfully proposed as novel biodegradable film for strawberry preservation. The multiple cross-linking (e.g. Schiff base interactions, metal coordination and hydrogen bonds) consumed the polar groups on chitosan skeleton, impeding the interaction of moisture with matrix. When further cross-linked by Ca2+, the resistance to solubility of CS-CNF/VA25-Ca1.5 was increased significantly. Compared with pristine CS film (completely dissolved within 3 min), CS-CNF/VA25-Ca1.5 film remained intact more than 32 days at ambient and 24 h in hot water (60 degrees C). Furthermore, the optimized CSCNF/VA25-Ca1.5 possessed better puncture resistance than commercial plastic. Reinforced oxygen barrier (0.9 cm3 mu m/(m2 center dot d center dot Kpa)), UV blocking, and antioxidation (93.6%) can also be achieved for CS-CNF/VA25-Ca1.5. The preservation experiment revealed that the composite coating obviously prolonged the shelf life of strawberries to 7 days at ambient. This work proposed a novel perspective in constructing green chitosan-based active film packaging with anti-dissolution in high moisture.