Sorghum Bicolor L. leaf sheath polysaccharides: Dual frequency ultrasound-assisted extraction and desalination

• Published in: Industrial crops and products 2018-12, Vol.126, p.368-379
• Main Authors: Otu, Phyllis Naa Yarley, Haonan, Jiang, Cunshan, Zhou, Hongpeng, Yang
• Format: Article
• Language: English
• Subjects: Antioxidant activity; Ionic liquid aqueous two phase; Morphology; Rheology; Sorghum bicolor; Ultrasound-assisted dialysis
• ISSN: 0926-6690; 1872-633X
• DOI: 10.1016/j.indcrop.2018.10.032

[Display omitted] •d-Galactose was notably oxidized under dual frequency ultrasound dialysis.•Desalination of salt-rich phase polysaccharide solution was remarkably improved.•Ionic liquid purified polysaccharide had its original helical structure preserved.•Assisted dialysis speeded hydrolysis, reducing molecular weight of polysaccharide.•The rheology (elasticity) and morphology demonstrated strong correlation. Supramolecules extraction using single frequency ultrasound technology application has directional effect as a shortcoming. Thus, optimum disruption of materials for better yield is curtailed. One possible solution to this underperformance is the application of dual frequency ultrasound. Dual frequency ultrasound-assisted extraction (DF-UAE) of crude polysaccharide (SL-C80P) and ionic liquid aqueous two phase system (ILATPS) purified polysaccharide (SL-D10P) of sorghum (Sorghum bicolor L.) leaf sheath was achieved using response surface methodology (RSM). Experimental yield for crude and purified polysaccharide (14.10% and 97.17%) respectively was found to be very close to the predicted (14.88% and 97.40%). Higher desalination levels of (SL-D10P) was also observed after DF-UA dialysis. Surface morphology under scanning electron microscopy and molar ratios of monosaccharides composition of the two samples were different, but Fourier transform infrared spectroscopy was similar. Crude and purified polysaccharides were of helical structures as demonstrated by the congo red assay and recorded molecular weights (1,202,000 and 12,950 g/mol) respectively. The sample, (SL-D10P) displayed more elasticity whiles (SL-C80P) showed more viscosity in rheological terms. Finally, (SL-D10P) aggregated in water, detachable by heat and possessed a notable ABTS scavenging ability, thus remarkable potential for biomolecules protection. In conclusion, a better extraction yield of polysaccharides was achieved.