Improvement of resveratrol release performance and stability in extruded microparticle by the α-amylase incorporation

Delivery of biological active substances with the sustained-release microcapsule is a common practice in the food industry. There were many kinds of methods to prepare the sustained-release microparticle, however their portability was the obvious shortcoming. This study presented a simple preparation process of microparticle (particle) with the extruded starch as wall material, resveratrol as the core material and the thermostable alpha-amylase as the release-improvement reagent (ESRA). The extruded microparticle containing starch and resveratrol (ESR) performed 58.2% release ratio of resveratrol within 5 days water immersion, whereas the alpha-amylase improved the release performance of the ESRA with 86.7% release ratio of resveratrol. Resveratrol release induced by the disintegration of microparticle was in accord with the size decrease observed by the particle size analyser. Lightstability of incorporated resveratrol was increased, but the extrusion package had no contribution in improving the thermostability of resveratrol. FT-IR, XRD and SEM were employed to investigate the change of molecular link between resveratrol and starch, crystal collapses of starch and microparticle morphology. This preparation process had a broader range of application, which could embed the solid powder and liquid compounds.