Combined recovery of polysaccharides and polyphenols from Rosa damascena wastes

Abstract

The industrial production of rose oil generates huge amounts of waste, and its potential for integrated utilization is underexplored. A combined method for the recovery of biologically active substances from waste rose (Rosa damascena Mill.) biomass was investigated and proposed in the present study. It comprised preliminary ethanol treatment of the wastes aimed at the extraction of polyphenol substances and subsequent fractional extraction of polysaccharides. The results suggested that the optimal ethanol concentration for integrated recovery was 70%. Different polysaccharide fractions were extracted and investigated for the first time from the alcohol insoluble residues (AIRs) by consecutive fractional extraction with water, oxalate, diluted acid and alkali. The neutral sugar compositions of the polysaccharides suggested that they were pectic-type polysaccharides. The differential thermal analysis of the isolated polysaccharides showed that their thermal stability was in the 220–230°C range. The overall yield of polysaccharides (25.3%) and polyphenols (4.4%) suggested that the waste rose biomass could serve as a valuable source of biologically active substances. As a result of the present study, a technological scheme for combined waste rose biomass utilization was proposed. On the basis of the technological operations and the energy assessment, calculations of the average costs of combined polyphenols and polysaccharides recovery were presented. An additional advantage of the integrated approach is that it could be further combined with other methods and applied to other essential oil plant wastes.