Microencapsulation of phenolic compounds extracted from sour cherry pomace: effect of formulation, ultrasonication time and core to coating ratio

Sour cherries (Prunus cerasus L.) contain phenolic compounds that decrease the proclivity to several chronic diseases such as types of cancer and cardiovascular diseases. The objective of the study was to investigate the effects of different coating materials, ultrasonication time and core to coating ratio on encapsulation of phenolic compounds extracted from sour cherry pomace. For this study, maltodextrin and gum arabic were chosen as coating materials. Different maltodextrin/gum arabic ratios (10:0, 8:2, 6:4) (total solid content 10 %) and two different core to coating ratios (1:10 and 1:20) were used. Emulsions were prepared using ultrasonication at 160 W power and 20 kHz frequency for different time periods (5-30 min). Then the emulsions were freeze-dried for 48 h to obtain the microcapsules. Encapsulation efficiency, surface morphology, particle size, antioxidant activity and color of microcapsules were determined. The microcapsules having core to coating ratio of 1:20 were found to have smaller particle sizes and higher encapsulation efficiencies (78-92 %) than those with a core to coating ratio of 1:10 (encapsulation efficiency 70-85 %). Increasing gum arabic ratio in the coating material increased encapsulation efficiency. Capsules prepared by sonication for 20 min and with a core to coating ratio of 1:20 can be selected as the best conditions for encapsulation of phenolic compounds from sour cherry pomace.