Extraction of Oleuropein Rich Extract from Olive Leaf by Ultrasonic Assisted Extraction Method, its Encapsulation with a Nano Technological Method and use in a Preperation of Functional Beverage
Project no. 22560 · Status: Kapanmış · 2020
Summary
The added value of the olive leaf, which is obtained as a waste in the production processes of olive and olive oil production, is increasing gradually due to the high content of phenolic compounds in its structure. In this project, it is aimed to extract the phenolic components from the olive leaves by ultrasonic method, to encapsulate the extract containing oleuropein with ionic gelation method and to use it to enrich kefir. The olive leaf used in the study was dried and ground. Then, preliminary experiments were carried out to determine the solvent type and solid: solvent ratio to be used in the extraction. As a result of preliminary trials, the highest extraction yield, total phenolic content and antioxidant capacity values were obtained with 1/20; solid/solvent ratio and at 90-10% ethanol-water concentration, respectively. Olive leaves containing high oleuropein in its composition were extracted by ultrasonic extraction method with specific process variables; temperature (30,35,40°C), time (5,10,15 min) and amplitude (40,70,100 %) according to the Box-Behnken experimental design, targeting maximum yield, total phenolic content and antioxidant capacity. The optimum point in the ultrasonic extraction process was determined as 5.31 min, 39.27? temperature and 40.51% amplitude. The encapsulation process of the extract obtained under optimum extraction process conditions was carried out by ionic gelation method. The coating material combination to be used in the ionic gelation method was determined as sodium alginate-chitosan by preliminary experiments. After determining suitable coating material combination, the ionic gelation process conditions such as extract concentration (%), chitosan concentration (%), waiting time (min) variables were optimized according to the CCRD experimental design, targeting the encapsulation efficiency (%) and total phenolic content (mg GAE/g). The optimum microencapsulation process conditions were determined as 1% extract concentration, 0.5% chitosan concentration and 11.24 minutes waiting time. Samples microencapsulated under optimum conditions and the extract were added to the model food, kefir and sensory analysis was performed. According to the sensory analysis results, the product kefir containing microencapsulated extract was acceptable.