Contents lists available at ScienceDirect Industrial Crops & Products journal homepage: www.elsevier.com/locate/indcrop Sorghum Bicolor L. leaf sheath polysaccharides: Dual frequency ultrasound- assisted extraction and desalination Otu Phyllis Naa Yarley, Haonan Jiang, Cunshan Zhou ⁎ , Hongpeng Yang School of Food and Biological Engineering, Jiangsu University, Zhenjiang, 212013, China ARTICLEINFO Keywords: Sorghum bicolor Ionic liquid aqueous two phase Ultrasound-assisted dialysis Morphology Rheology Antioxidant activity ABSTRACT Supramolecules extraction using single frequency ultrasound technology application has directional efect as a shortcoming. Thus, optimum disruption of materials for better yield is curtailed. One possible solution to this underperformanceistheapplicationofdualfrequencyultrasound.Dualfrequencyultrasound-assistedextraction (DF-UAE) of crude polysaccharide (SL-C 80 P) and ionic liquid aqueous two phase system (ILATPS) purifed polysaccharide (SL-D 10 P) of sorghum (Sorghum bicolor L.) leaf sheath was achieved using response surface methodology (RSM). Experimental yield for crude and purifed polysaccharide (14.10% and 97.17%) respec- tivelywasfoundtobeveryclosetothepredicted(14.88%and97.40%).Higherdesalinationlevelsof(SL-D 10 P) was also observed after DF-UA dialysis. Surface morphology under scanning electron microscopy and molar ratios of monosaccharides composition of the two samples were diferent, but Fourier transform infrared spectroscopy was similar. Crude and purifed polysaccharides were of helical structures as demonstrated by the congo red assay and recorded molecular weights (1,202,000 and 12,950g/mol) respectively. The sample, (SL- D 10 P) displayed more elasticity whiles (SL-C 80 P) showed more viscosity in rheological terms. Finally, (SL-D 10 P) 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. 1. Introduction Well known classical methods of organic compound extraction in- cludes the typical use of solvents, heat and / or agitations. Modernization has managed to improve upon the efciency of these ancient methods of extraction by the application of various extraction techniques including high powered ultrasound, which principally uses energyobtainedasaresultsofcollapsingcavitationalbubblestoensure a very high solvent penetration of extracting solvent into the sample matrices, increasing mass transfer of interface (Knorr, 2003; Rui, 2003) (Vinatoru, 2001)(Vilkhu et al., 2008). Dual frequency type of ultra- sound reactor ensures a strong interference pattern in the reactor that curtails any form of directional efect. Single frequency type of ultra- sound reactor on the other hand possess a directional sensitivity of the ultrasound feld causing a varying volumetric energy dissipation in the reaction medium, thus limiting extraction yield (Moholkar, 2009).Ina previous work (yet to be published), single frequency ultrasound re- actor was used to extract crude polysaccharide from Moringa oleifera Lam. leaves and a total yield of (9.24%) was obtained. Leaching (Swamy and Narayana, 2001), medical application (Sokka et al., 2005) (Barati et al., 2007) and degradation of recalcitrant organic pollutants (Gogate et al., 2003; Wang et al., 2006) are a few areas in which dual frequency ultrasound has been applied. This work thus aimed at using dual frequency ultrasound to improve the extraction yield of poly- saccharides. Purifcation of polysaccharides after defatting samples includes deproteinization, classically achieved by the use of various organic solvents. In another work (yet to be published) ILATPS, [C 8 mim]Cl / K 2 CO 3 was used to purify extracted M. oleifera leaves polysaccharide using single frequency ultrasound reactor and a (75%) pure poly- saccharide was extracted into the salt-rich phase. Therefore interacting ILATPS with dual frequency ultrasound (DF-U) for purifcation of ex- tracted crude polysaccharide in this work may also cause increase in extraction yield of purifed polysaccharides. Dialysis principally involves the difusion of small molecules across selectedporesizeofdialysismembraneuntilequilibriumconcentration is established between sample solution and dialysate. It is also well known that if equilibrated dialysate is replaced with fresh dialysate, difusionwill furtherreducetheconcentrationofthesmallmoleculesin the sample. Furthermore, the established principle of ultrasound which involves the generation and collapsing cavitational bubbles, has the ability to cause greater penetration of dialysate into sample solution https://doi.org/10.1016/j.indcrop.2018.10.032 Received 22 June 2018; Received in revised form 20 September 2018; Accepted 10 October 2018 ⁎ Corresponding author. E-mail address: cunshanzhou@163.com (Z. Cunshan). Industrial Crops & Products 126 (2018) 368–379 0926-6690/ © 2018 Elsevier B.V. All rights reserved. T