Optimization of Preparation Process of Lichi Polyphenols Microcapsules and Its Characteristic Analysis

Microcapsules of lichi polyphenols were prepared by complex coacervation method with sodium alginate and chitosan as wall materials, improving the stability of lichi polyphenols. With embedding rate as index, the preparation conditions were optimized by orthogonal experiment, and its in vitro release properties, thermal stability, antioxidant activity were investigated. The results showed that the optimum preparation process of lichi polyphenols was as follows: the mass fraction of sodium alginate, calcium chloride, chitosan and lichi polyphenols were 3.5%, 3%, 2%, 0.8%, embedding time was 1 h. The obtained microcapsules exhibited a uniform particle size and high embedding rate of 95.74%. The microcapsules had great target-releasing behavior in simulated intestinal fluid (pH6.86), the release rate of polyphenols was 19.66% and the ABTS+ free radicals scavenging rate was 20.30% at 3 h. Compared with the unembedded lichi polyphenols, the microcapsules had higher polyphenols retention rate at the same condition of temperature (increased by 2.09%～3.34%), which showed that the microcapsulation of lichi polyphenols could effectively improve the thermal stability of lichi polyphenols.