Preparation and Characterization of Emulsion-based Peony Seed Oil Microcapsule.

Microcapsules were constructed with starch sodium octenyl succinate (SSOS), β-cyclodextrin (β-CD), and pectin walls and peony seed oil cores. A rheological phenomenon occurred in which the emulsion initially behaved like a shear-thickening fluid and then a shear-thinning fluid within a shear range. The emulsion exhibited good stability under low amplitude stress; however, as amplitude increased the concentration of pectin played an important role in maintaining the stability of the emulsion system. The optimum embedding yield of peony seed oil (92.5%) was achieved with a ratio of 70% SSOS, 22.5% β-CD, and 7.5% pectin. This ratio produced 4.521 μm particles with the lowest surface-oil content (2.60%) and moisture content (1.76%). The peony seed oil microcapsules were spherical with smooth surfaces and a synchronous thermogravimetric analysis showed they possessed good thermal stability. Encapsulation increased the induction period to 5-7 times that of unencapsulated peony seed oil.