Studies on the chemical modifications of Rosmarinus officinalis essential oil hydrodistillation process (HD) by using 5% citric acid (CA-HD) and 5% trisodium citrate (TSC-HD) as a water phase were performed. Composition of essential oils obtained in conventional and modified conditions was analyzed by gas chromatography with mass selective detector method (GC-MS) and compared. Antioxidant activity of all essential oils was determined spectrophotometrically by using DPPH radical scavenging method. It was found that applied modifications of hydrodistillation process enhanced yields and antioxidant activity and the best results were obtained using 5% citric acid as a modifier. Effect of this modification on fungicidal activity of essential oils against 8 various fungi strains (Alternaria alternata, Botrytis cinerea, Fusarium culmorum, Phythophtora cactorum, Rhizoctonia solani, Phythophtora infestans, Sclerotinia sclerotiorum and Ascosphaera apis) was also determined and in most cases enhanced activity was observed.
