Lavender (Lavandula angustifolia Mill.) industrial by-products as a source of polysaccharides

Abstract

Apart from the main aroma products, the lavender essential oil industry generates huge quantities of undervalorized biomass, which was discarded nearby to the distilleries or used as a fertilizer. Therefore, the current study was performed to explore the hypothesis that the lavender waste biomass could be additionally utilized as a source of polysaccharides . An industrial residue from supercritical CO 2 -extraction (CO2-L) and steam-distilled lavender (SD-L) were used as source material after preparing the alcohol-insoluble material. Acid-soluble polysaccharides (ASPs) were obtained from CO2-L (6.97 ± 0.14%) and SD-L (5.95 ± 0.23%). The monosaccharide composition revealed that polysaccharides were composed mainly of galacturonic acid 672.44 ± 4.89 µg mg −1 (CO2-L) and 619.17 ± 5.23 µg mg −1 (SD-L). The ASPs were characterized by a medium degree of methyl-esterification (50%) and a low degree of acetylation (<3%). The pectin nature of lavender ASPs was confirmed by infrared and NMR spectroscopy experiments. ASPs’ gelling behavior was investigated by examination of high sucrose (1.25% polysaccharide and 60% sugar (w/w)) and Ca 2+ (1.25% polysaccharide (w/w) and 6 mmol/L Ca 2+ ) gel systems and compared with the gelation of two commercial citrus pectins. Both CO2-L and SD-L ASP were able to produce Ca 2+ gels, while in the presence of sucrose only the CO2-L polysaccharide yielded gel. ASPs were included in the hand cream formulation. It was found that both polysaccharides increased the apparent viscosity compared to the control hand cream. This might lead to the conclusion that lavender wastes could be regarded as a natural source of polysaccharides having valuable properties to enable incorporation into cosmetic products. • Lavender by-products from CO 2 extraction (CO2-L) and distillation (SD-L) were studied. • CO2-L and SD-L yielded 6.97 ± 0.14% and 5.95 ± 0.23% polysaccharides, respectively. • Monosaccharide composition and NMR studies suggested pectic type structure. • CO2-L and SD-L polysaccharides yielded relatively strong gels in presence of Ca 2+ . • CO2-L and SD-L polysaccharides increased the apparent viscosity of hand creams.