Subcritical Water Extraction of Rosa Alba L. – Technology and Quality of the Products

Green subcritical water extraction has been applied with the white oil-bearing rose Rosa alba L. The two factor modeling process revealed that 150 °C and 30 minute treatment resulted maximum yield of phytochemicals: essential oil, phenolic compounds, total sugars, proteins and simple sugars. A quantitative and qualitative analysis of the products was performed. The essential oil contains mainly phenylethyl alcohol, citronellol, geraniol and hydrocarbons (paraffins). The phenolic substances were represented by phenolic acids (gallic acid: 30.92-113.37 µg/mL; ferulic acid: 44.50-99.96 µg/mL; rosmarinic acid: 25.27-80.47 µg/mL and protocatechuic acid: 13.05-25.48 µg/mL), flavonoids (both quercetin and kaempferol: 8.35-8.56 µg/mL and their glycosides: 15.91-58.08 µg/mL). The monosaccharides determined were glucose (3.09-15.29 mg/mL), galacturonic acid (1.02-2.34 mg/mL), galactose (0.18-0.78 mg/mL), rhamnose (0.17-0.48 mg/mL) and xylose (0.07-0.17 mg/mL). The content of total phenols, flavonoids and antioxidant activity were reported by DPPH, ABTS, FRAP and CUPRAC methods. The complex composition and activity of the extracts suggests their application directly as a food supplement or in cosmetic preparations.