Efficient extraction of psyllium seed husk polysaccharide by utilizing the viscosity-reducing effect of low-concentration ethanol at high temperatures

The high viscosity of psyllium seed husk polysaccharide (PSHP) significantly restricts the solid-liquid ratio during the extraction process, especially in large-scale manufacturing operations. In this study, an efficient extraction method for PSHP using low-concentration ethanol at high temperatures was developed. The results demonstrated that the solid-liquid ratio for total ethanol-water extracted polysaccharide (TEP) extraction using 25% ethanol was 8:200, which is sevenfold higher than that of the traditional hot water extraction method. The results of the structural characterization demonstrated that TEP preserved the integrity of its molecular structure and exhibited a high molecular weight of 2587 kDa. Furthermore, the conformational and rheological analyses revealed that the substantial contraction of molecular chains in the presence of ethanol resulted in a reduced viscosity of TEP across a broad temperature range, thereby ensuring high efficiency of the extraction process. Therefore, this method preserves the integrity of the TEP molecular structure while enhancing the extraction efficiency, demonstrating considerable potential for large-scale TEP production. • The viscosity of TEP decreased significantly at 25% ethanol concentration. • The extraction of TEP using low-concentration ethanol is more efficient. • The solid-liquid ratio for TEP extraction using 25% ethanol was determined as 8:200. • Low-concentration ethanol preserved the integrity of the molecular structure of TEP.