Chitosan-based hydrogel coating via electrostatic spraying for fruit preservation.

Fruit coating constitutes a viable technique for quality maintenance and shelf-life extension. However, traditional coating methods, such as dipping or brushing, suffer from issues including high cross-contamination risks, low utilization efficiency, and uneven coating distribution. This study proposed an innovative coating for fruit preservation via electrostatic spraying strategy. The coating process involved the electrostatic deposition of powder materials, including quaternized chitosan (qCS) and oxidized hyaluronic acid (OHA), followed by mist-spray rehydration, triggering rapid Schiff bases between qCS and OHA to form hydrogel coatings within seconds. The bioactive melatonin (MLT) was incorporated into this matrix. The resulting MLT/qCS-OHA coating exhibited improved tensile properties and antioxidant activity. It significantly inhibited strawberry decay, promoted the total phenolics and anthocyanins accumulation, and maintained overall fruit quality. With operational simplicity, high material utilization efficiency, reduced cross-contamination risk, and uniform coverage, this electrostatic spraying strategy presents a promising and practical approach for scalable food preservation applications.