Preparation of Thymol-Containing Microcapsules and Its Application in Strawberry Preservation

As an antioxidant and broad-spectrum antibacterial agent, thymol has some disadvantages such as poor solubility, low stability and strong irritating odor, restricting its application in food preservation. In order to overcome these shortcomings, thymol-containing microcapsules were prepared by the saturated aqueous solution method using thymol as the core material and β-cyclodextrin as the wall material, and the sustained release performance, antibacterial and antioxidant capacity of the microcapsules were evaluated. Meanwhile, its structure was characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric (TG) analysis, and its efficacy in preserving strawberry quality was analyzed. The results showed that thymol was successfully embedded in β-cyclodextrin and the thermal stability of the microcapsules was significantly improved. The maximum cumulative amount of thymol released from the microcapsules was 41.16% after 360 min. When used at a dosage of 25 mg, the microcapsules had the strongest antibacterial effect on Escherichia coli and Staphylococcus aureus. At a concentration of 10 mg/mL, it scavenged 81.40% of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals. The microcapsules reduced the decay incidence and loss rate by 26.34% and 19.63%, respectively on the 10th day of storage compared with the control group, slowed the decrease in hardness and soluble solids content (SSC), and better maintained the appearance, color, texture and flavor. Thymol-containing microcapsules could delay the spoilage, effectively maintain the quality, and prolong the shelf life of strawberry at room temperature.