Study on microencapsulation of lycopene by spray-drying

Lycopene microcapsules were prepared by a spray-drying method using a wall system consisting of gelatin and sucrose. The effects of technological parameters including the ratio of core and wall materials, ratio of gelatin and sucrose, homogenization pressure, inlet temperature, feed temperature, and lycopene purity on encapsulation yield (EY), encapsulation efficiency (EE) were investigated. The resulting microcapsules were characterized in terms of lycopene isomerization, storage stability, PS, PSD, and outer and inner structures. Results showed that EY and EE were significantly affected by the ratio of core and wall materials, ratio of gelatin and sucrose, homogenization pressure, inlet temperature, feed temperature, and lycopene purity. The optimal condition was determined as follows: the ratio of gelatin/sucrose of 3/7 and the ratio of core and wall material of 1/4, feed temperature of 55 °C, inlet temperature of 190 °C, homogenization pressure of 40 MPa, and lycopene purity of not less than 52%, at which the microencapsulated lycopene showed some isomerization, but a good storage stability. SEM and XRD analysis showed that lycopene microcapsules had a regular spherical shape with a PSD of 2–15 μm, mean PS of 5 μm, smooth outer surface, “bee net”-like interior structure, and lycopene was embedded in the wall system consisting of gelatin and sucrose. This study would be helpful to the industrial application of lycopene.