Chemical and functional properties of rose cactus (Pereskia bleo) mucilage as affected by different purification mediums

Rose cactus (Pereskia bleo) leaves contain a complex polysaccharide called mucilage, which its functionality in foods should be better explored. This study aimed to investigate the effects of different purification mediums on the chemical and functional properties of rose cactus mucilage (RCM). Crude mucilage from leaves of rose cactus was extracted by using 0.14 M NaOH solution at 70°C. Three different purification mediums were employed i.e. isopropanol, saturated barium hydroxide and Fehling solution to obtain mucilage that pure in chemical composition with improved functional properties. Of all mediums, saturated barium hydroxide significantly (p < 0.05) gave the highest recovery yield (52.61%) of RCM, with the best properties especially in terms of crude protein content (26.01%), solubility at 60°C (87.19%), water holding capacity (WHC) (393.88%) and also with emulsifying capacity and emulsion stability (at 1% solution) of 14.11% and 10.44%, respectively. The values were also significantly (p < 0.05) higher than those recorded for crude mucilage. Fourier transformed infrared spectra revealed that RCM was characterized by a β-(1à4)-D-glucosidic main backbone while galactose, mannose, arabinose and uronic acid were four important monosaccharides identified. The findings signify that purification using saturated barium hydroxide could be used to improve the chemical and functional properties of RCM ensuring its wider application in the food industry.