Changes of phenolic compounds in propolis at different biotransformation conditions

Propolis is a valuable bee product with complex content. Propolis is a resinous material collected by honeybees (Apis mellifera L.) from various plant sources. The bees carry the materials to hive which they collect from different parts of the plants. Propolis comes to as a result of mixing these substances with salivary secretions and wax with the help of the jaws of the bees. In this thesis, the change of phenolic components in propolis under different biotrasformation conditions was investigated by considering the fact that the phenolic compounds contained in propolis can become more useful after biotransformation and can be used in different application areas. Different solvents (ethanol, polyethylene glycol and water), different inoculation rates (1.5%, 2.5%, 3.5%), different cultures (Lactobacillus plantarum ISLG-2, Lactobacillus plantarum ATCC® 8014, Lactobacillus plantarum Visbyvac) and ultrasound application (5 min, 10 min, 15 min) were used during biotransformation. Propolis samples subjected to different biotransformation conditions were analyzed by UPLC/MS-MS method, total phenolic compound analysis by Folin Ciocalteu method and antioxidant activity analysis by trolox equivalent antioxidant activity (TEAC), 2,2-diphenyl-1-picrylhydrazyl radical scavenging antioxidant activity (DPPH) and iron (III) reducing antioxidant activity (FRAP) method. As a result of the study, the effects of different solvents, cultures and ultrasound applications on phenolic compounds have changed and it was found that each parameter selected according to the target phenolic component could have a qualitative effect.