Abstract:

Olive oil was microencapsulated by ultrasonic spray drying method to investigate the influence of inlet air temperature on water and encapsulation efficiency of olive oil microcapsules. And then the storage stability of microencapsulated olive oil microencapsulation was also evaluated. The results of the ultrasonic-spray microencapsulation of olive oil showed that the surface color of the olive oil microencapsulation was deepened, some olive oil was dissolved out and the encapsulation efficiency of olive oil was reduced owing to the higher inlet temperature. However, the too low inlet temperature leaded to the higher moisture content of the olive oil microencapsulation. The optimization of olive oil microencapsulation by ultrasonic spray drying conditions was obtained, which was the inlet temperature of 180 ℃ and feed rate of 6 r/min. The encapsulation efficiency of olive oil microcapsules prepared under this conditions reached 98.2%. The stability was studied after olive oil microencapsulation stored under the different conditions of illumination, temperature and humidity for 30 days. The results shown that the peroxide value and acid value of microencapsulated olive oil under light were 1/5 and 1/3 of that of unencapsulated olive oil, respectively. Under dark condition, the peroxide value and acid value of microencapsulated olive oil were about 2/3 of that of unencapsulated olive oil. Owing to the increase of temperature, the peroxide value of unencapsulated olive oil was doubled, and the maximum acid value increased by 77.8%, while the peroxide value of microencapsulated olive oil increased by only 15%, and the maximum acid value increased by 40.5%. The peroxide value and acid value of encapsulated olive oil were lower than those of unpacked olive oil, indicating that the microencapsulation delayed oxidation of olive oil and improved the storage stability of olive oil.

Key words: olive oil, inlet temperature, feed rate, light, temperature, humidity