The preservation performance of chitosan coating with different molecular weight on strawberry using electrostatic spraying technique.

In this study, chitosan (CH) coating with different number-average molecular weight (MW, ca. 5, 19 and 61 kDa) was electrostatic sprayed on strawberry. The effects of MW on strawberry quality changes were evaluated during 15 days of storage at 4 °C. The qualities of strawberry included mold growth, weight loss, firmness, total soluble solids (TSS), pH, flavonoids content, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content. Results showed that CH coating could significantly maintain the strawberry qualities during storage compared to uncoated treatment. CH coating with 61 kDa was more effective in retarding the increases of pH and MDA, and could better maintain flavonoids content. However, MW had no significant impact on mold growth, weight loss, firmness, SOD activity of coated strawberry. According to evaluation criteria, CH coating with 61 kDa had better performance on strawberry preservation with the highest synthetic value (6.93), and could be used to maintain quality and prolong the shelf life of strawberry during cold storage.