Sterilization of Natural Rose Water with Nonthermal Atmospheric Pressure Plasma

In this study, nonthermal atmospheric pressure plasma (NTAPP) method was performed for the sterilization of natural rose water which has a great potential as drug and food additive. NTAPP is applied to rose water containing mesophilic aerobic bacteria, mold and yeast. Experiments were carried out at a voltage of 500V, a rotating speed of 500rpm and a plasma power of 100W. The effect of various plasma treatment times (15, 30 and 45s) on the inactivation of total viable (aerobic count), mold and yeast was evaluated. Scanning electron microscopy images showed that the microorganism population in rose water was reduced after plasma treatment for 45s. After 45s of plasma treatment, inactivation of mesophilic aerobic bacteria, mold and yeast cells are decreased similar to 70%. This sterilization effect may be associated with cell death, which may be attributed to oxidative stress and other damage effects caused by the applied plasma. After sterilization process, the composition of volatile oils obtained from rose water samples was detected using gas chromatography-mass spectrometry. The chemical composition of rose water before and after plasma sterilization was evaluated by Fourier-transform infrared spectroscopy.