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BACKGROUND: Thymol (Thy) is a natural bioactive agent which possesses various properties and has been widely used in medicine and food industries. However, its poor bioavailability can limit its application.RESULTS: In this study, Thy was interacted with chitooligosaccharide (COS) as Thy-COS complex via an ionic crosslinking method using sodium tripolyphosphate as a crosslinker. The characteristics and thermal stability of Thy-COS were evaluated by ultraviolet-visible (UV-vis), Fourier-transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance ( 1 H-NMR) and thermogravimetric analysis, and its antioxidant and antibacterial properties were also evaluated. The highest loading capacity of Thy (52.3%) in Thy-COS formed at mass ratio of 1:5. Results indicated the Thy-COS complex was formed mainly by hydrophobic interactions and hydrogen bonds. Upon complexation, the thermal stability, antioxidant and antibacterial activity of Thy were significantly improved. Thy-COS complex was made into a coated film for Nanguo pears and greatly improved its storage quality. Thy-COS delayed the weight loss and softening of Nanguo pears and kept more vitamin-C content (2.12 mg (100 g) −1 ). CONCLUSION: In conclusion, Thy-COS was successfully prepared and improved antioxidant and antibacterial properties of Thy, which has great potential in the food industry.

The ozone fumigation device with the self‐circulation function and the low‐temperature fluctuation box with precise temperature control were, respectively, designed to study the effect of the combination of vacuum precooling with ozone fumigation or low‐temperature fluctuation treatment in the quality modifications of sweet cherries during cold storage. The results showed that all the three treatments had a positive effect on quality maintenance. Although precooling combined with low‐temperature fluctuation slightly damaged the fruit after 9 days of storage, the combination of precooling and ozone can better maintain the luster of the fruit and retain the content of total soluble solids, the titratable acid, and anthocyanin during the entire storage period. Meanwhile, it delayed fruit softening, inhibited the accumulation of malondialdehyde and activity of polyphenol oxidase. Additionally, the ultrastructure and cell wall material content indicated that ozone stress could induce shrinkage of stoma and maintain morphology of cell wall and cell structure. Practical applications Sweet cherries are delicious and juicy, but they have quite a short shelf life, limited edible period, and high cost of deep processing. Refrigeration, precooling, and ozone are effective measures to extend the shelf life of fruits and vegetables in the field of postharvest preservation. However, the large flow of personnel in the conventional walk‐in cold storage results in low precooling efficiency and significant temperature fluctuations, which make the cherries perishable. In addition, ozone has been evaluated as a promising disinfectant for fresh fruits, which may be used to induce resistance to postharvest decay of fruits and vegetables. Thus, in this study, a combination of precooling with ozone fumigation or low‐temperature fluctuation was used to explore the postharvest quality of sweet cherries. All results indicated that vacuum precooling combined with regular ozone fumigation treatment may be a promising technology for the preservation of sweet cherry fruit, which can effectively improve the storage quality.

To prevent microbial contamination in foods and medical tools, we prepared a novel antibacterial material nano-silver loaded poly(styrene-co-acrylic) (nAg-PSA) composites by in situ reductions. The nAg-PSA was characterized by scanning electron microscope, transmission electron microscopy, energy dispersive X-ray spectroscopy and thermogravimetric analysis. The antibacterial properties of nAg-PSA against Escherichia coli and Staphylococcus aureus were systematically evaluated, and the underlying mechanism was investigated. Results showed that the silver nanoparticles were successfully loaded onto PSA microspheres, highly dispersed on the surface of nAg-PSA nanoparticles. The nAg-PSA nanoparticles all showed significant antibacterial effects, among which nAg-PSA4 had maximum diameters of inhibition zones against the Gram-negative E. coli (1.18 mm) and the Gram-positive S. aureus (1.29 mm), respectively, which closely related to the size and density of silver nanoparticles covered on the surface.