Pectin substances of essential-oil crops II. Isolation and characterization of the pectin ofRosa canina

Abstract

Continuing a study of the pectins of essential-oil crops of the Crimea [i] in order to utilize wastes, in the present paper we give information on the pectin isolated from the petals of the rose Rosa canina L. (family Rosaceae). By heating the rose petals (variety Krasnaya Krymskaya) with benzene--ethanol (3:1) at 50-60°C for 5-6 h three times, followed by treatment with hot water, we eliminated lipids, pigments, and water-soluble polysaccharides. The pectins were extracted with mixture of 0.25% solutions of ammonium oxalate and oxalic acid at 60-70°C, followed by precipitation with ethanol. The precipitate was dialyzed against distilled water. The residue after dissolution in buffer solution was again precipitated with ethanol (the operation was repeated three times). The precipitate was subjected to freezedrying. Yield 2-3%. The pectin isolated, with [a]~ ° + 219 ° (e 0.075; N20), consisted of a flocculant white or pink powder. It was readily soluble in water andpractically insoluble in the majority of organic solvents. Elementary analysis (%), C, 32.51; H, 3.75; N, 1.97.