Preparation And Release Behavior Of Peony Seed Oil Microencapsulation

Peony seed oil is rich in polyunsaturated fatty acids,can be oxidized easily in the transportation and storage process,greatly reducing its nutritional value.Microencapsulation technology can effectively delay the oxidation of peony seed oil and reduce the nutrient loss of peony seed oil during processing,transportation and consumption.In this paper,lecithin and whey protein isolate(WPI)were used as emulsifier and wall material of the oil microcapsules.The effects of the interaction mechanism between lecithin and WPI on the microcapsule emulsion system were studied,the peony seed oil microcapsules were prepared by spray drying method,and their basic physical and chemical properties,storage stability and in vitro digestion and release behavior were evaluated.(1)The interaction mechanism between WPI and lecithin was investigated by fluorescence spectroscopy and the results indicated that lecithin can quench the fluorescence of WPI through a static quenching procedure and the interaction of lecithin with WPI was driven mainly by hydrophobic force.In emulsion,the droplet size,?-potential,and viscoelastic properties of the emulsion significantly decreased at low lecithin concentrations(0.25%~0.75%).However,with the increased in lecithin content,the ?-potential increases slightly and the stability of the emulsion decreases and the particle size of the emulsion almost unchanged due to the competitive adsorption of lecithin and WPI at the interface.(2)Peony seed oil microcapsules were prepared by spray drying,and their physical and chemical properties were determined.The results showed that the encapsulation rate of microcapsule samples was higher than 90% at 0.50%~1.00% lecithin content.The average particle size of microcapsules is small and the distribution is uniform,the water content is low,the solubility is high,and the thermal stability is good.FTIR analysis found that the characteristic peaks of the peony seed oil and the wall material were weakened by microencapsulation,which indicated that the wall material had a good wrapping effect on the peony seed oil.The microscopic structure of microcapsules was analyzed by SEM and CLSM.It was observed that the microcapsules were spherical,the surface was round and smooth,and the thickness of the microcapsules was uniform.Peony seed oil was evenly distributed in the wall structure.The spray drying process did not affect the fatty acid composition and relative content of the peony seed oil.(3)The storage stability of peony seed oil microcapsules was studied and the results showed that the PV and TBA values of peony seed oil microcapsule prepared by WPI and corn syrup were used as wall material and 0.75% lecithin.The highest retention rate and the smallest loss of polyunsaturated fatty acid content were found in this formula,and the storage period is expected to reach 192 days.The diffusion behavior of the microcapsules in the accelerated storage process was observed by CLSM.As the storage time was prolonged,the core material of the microcapsules gradually diffused to the surface,the degree of adhesion of the particles increased and the microcapsule was deformed.(4)In vitro digestion model was used to study the in vitro release behavior of peony seed oil microcapsules.The total amount of microcapsules released to 84% in the digestion process.The controlled release of microcapsules ensures that most of the core material is released in the intestine.LCSM was used to observe the release behavior of microcapsules in simulated in vitro experiments.During the digestion process,the particles size gradually decreased,protein-based wall materials in the protease under the action of hydrolysis digestion,peony seed oil gradually released,which were benefited to polyunsaturated fatty acids and other functional ingredients in the human gastrointestinal digestion and absorption.