Microencapsulation Of Mint Oil

Microencapsulation, which transforms liquid into easily handled solid powder, has been gradually widely used in food industry. Microencapsulation stabilizes the core material, controls the release of the core material and enhances its resistance to heat, oxygen, moisture, and incompatible components. This paper focused on the preparation of encapsulated mint oil with different wall material.The volatile components of mint oil were determined by GC/MS. The mint oil was encapsulated byβ-cyclodextrin(β-CD), the optimal parameters were determined by orthogonal experiments, and showed as follows: ratio of core and wall material 1:8, 4hr, 50℃. Yield of encapsulated mint oil was 93.16%, and the mint oil loading was 10.35% (w/w) under the optimal conditions.Gum arabic and two kinds of starch octenylsuccinates (HI-CAP100 and N-LOK) were used as wall material to prepare the microencapsulated mint oil by spray drying. The yield and encapsulation efficiency with HI-CAP100 as wall material were higher than those with gum arabic. The optimal parameters of encapsulated mint oil with HI-CAP100 (40% mint oil loaded) were obtained by orthogonal experiments and showed as follows: solids content 45%(w/w), homogenizing pressure 35Mpa, dryer inlet temperature 195℃. Both the encapsulated yield and efficiency were 95% above. In additon, the retention rate of encapsulated mint oil was 91.96% after 6 months stored at 40℃.With HI-CAP100 as wall material, the glass transition temperature of encapsulated mint oil measured by DSC was 53℃, which indicated the encapsulated mint oil could stored at room temperature and showed good stability. The results of GC-MS indicated that the microencapsulation could efficiently prevent the changes of the volatile components. Scaned with scanning electron microscope (SEM), the microstructure of encapsulated mint oil was campact, which could prevent efficiently the volitilization of the mint oil during the period of storage.Both HI-CAP100 and N-LOK had good emulsifying stabilities. The mint oil emulsion prepared with HI-CAP100 showed better emulsifying stability than that with N-LOK, and the stability of emulsion decreased slightly with the increase of the mint oil. However, homogenizing pressure showed little influence on emulsion stability.The substitute degree of HI-CAP100 was higher than that of N-LOK, The molecule of HI-CAP100 has more hydrophobic group, and could reduce the interfacial tension more efficiently, which contributed to the stability of emulsion of mint oil. HI-CAP100 absorbed at the interface of water and oil and formed a film with molecular force, which showed good viscoelasticity. The interfacial viscosity increased obviously with increase of concentration...