Encapsulation of tomato oleoresin with zein prepared from corn gluten meal

Corn gluten meal (CGM), the major byproduct during starch processing, is a good source for zein extraction. Ultrasound treatment was used to extract zein from CGM. In comparison with conventional solvent extraction, extraction yield of corn zein was improved by ultrasound treatment. Zein obtained from ultrasound treatment was whiter and the emulsifying properties of zein were also improved. Zein was used as coating material to encapsulate the tomato oleoresin by spray-drying. Moisture content, particle yield and microencapsulation efficiency of powder increased with an increase in zein concentration. Microcapsules prepared by spray-drying had poor flowing properties. First-order reaction was used to determine the degradation of lycopene in the microcapsules. The results of controlled release showed that zein particles could protect most of the lycopene from being released in the stomach.