Investigation of in vitro antioxidant effects of microencapsulated rosemary essential oil

Microencapsulation is a technique used for the entrapment of a thin film with coating materials in the liquid droplets, the solid particles or gas components. Rosemary (Rosmarinus officinalis L.) is extensively used as medicinal plant due to its phenolic compounds. Rosemary essential oils have shown that antimicrobial, antioxidant, radical scavenger activities. Microcapsules of essential oils obtained with microencapsulation technique are more resistant to conditions shows good stability in the stomach; they slow absorption and limited digestible in the intestinal system, released easily in the large intestine as compared to those in free form. Microencapsulated essential oils also interacts with other components, compared to free form. The aim of this study is to determine the in vitro antioxidant properties and release properties of rosemary essential oil which encapsulated using alginate-starch in the system that simulates the in vivo intestinal system. Rosemary (Rosmarinus offcinalis L.) essential oil which used as natural antioxidants microencapsulated using alginate/starch as coating materials. Optimum microcapsules were prepared with 2,0 % (w/v) sodium alginate, 7,0 % (w/v) rosemary essential oil, 1,0 % (w/v) starch and cross-linked with 1,0% (w/v) CaCl2. Microencapsulation efficiency was determined as 87,16 %. The release properties of rosemary essential oil from the microcapsules which used starch and without starch were followed for 240 minute and released essential oil ratio changed linearly with time, 55,38 % and 64,44 % respectively. It was found that compared to free essential oil the microencapsulated essential oil has the 86,43 % and 72,67 % DPPH and ABTS scavenging activity respectively. Microcapsules obtained under optimized conditions presented a spherical shape with irregular surfaces and no fissures or cracks, and the mean diameter observed was 500-1000 μm.