Application of Thyme Oil Microcapsule Composite Coating in Mango Preservation

A natural preservative was prepared with thyme oil microcapsule as an additive. Taking gum Arabic as emulsifier, thyme essential oil as microcapsule core material and β-cyclodextrin as microcapsule wall material, thyme essential oil microcapsule (TEOM) was prepared by co-precipitation method. The samples were characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The natural preservative was prepared with starch as the coating substrate and thyme oil microcapsule as the additive. The preservation property of mango was studied. The results showed that, the structure of microcapsule is typical monoclinic crystal structure, the infrared spectrum showed that the essential oil had been embedded into the hydrophobic cavity of cyclodextrin. When the concentration of microcapsule was 0.6 and 16 mg/mL, microcapsules showed the optimal bacteriostatic effect on Escherichia coli, Bacillus subtilis, mango Colletotrichum gloeosporioides Penz and mango Botryodiplodia theobromae Pat, respectively. During the storage period, the indexes of mango hardness, titratable acid content and vitamin C showed a decreasing trend after the extension of the storage time, but the decreasing amplitude of 3%-TEOM/Starch group mango was less than that of the untreated group and 0%-TEOM/Starch group. On the 10th day of storage, the rate of weight loss was 2.2%, hardness was 11.8 N, titratable acid content 0.145%, soluble solid content 15.0 Brix and vitamin C 73 mg/kg of 3%-TEOM/Starch group mango, compared with the other groups, the composite coating preservative reduced the loss of nutrients such titratable acid content, soluble solid content and vitamin C(P<0.05). It was indicated that thyme essential oil microcapsules composite coating had a better preservation effect on mango.