Optimization of hydrocolloid extraction from serish root (eremurus luteus) using response surface method and examining physicochemical characterization of the optimized sample

The gums extracted from different sources have different functional and rheological properties compared to each other, and the extraction conditions have significant effects on these properties. Therefore, the study on the method of extraction and optimization of new sources of gums, due to different gum behaviors towards each other, has become more important. In this study, the optimization of extraction conditions for glucomannan of Eremurus Luteus powder (Serish) as a new source of hydrocolloid has been studied. For this purpose, the effect of temperature (30-80°C), water-to-solid ratio (50-100%) and time (1-4 hours) on the extraction yield, apparent viscosity, and solubility were optimized using the response surface methodology. The results showed that the quadratic model is the best model to describe the data. The optimized conditions were temperature of 79°C, water to solids ratio of 98.3 to 1 and extraction time of 3 hours and 12 minutes. Under these conditions, the apparent viscosity of 250 mPa.s, solubility of 53.99% and extraction yield of 72.43% were obtained. The results of chemical composition analysis showed that the optimal sample based on dry weight had 86.25% carbohydrates, 6.22% (protein), 6.13% (moisture) and 4.17% (ash). The results of monosaccharide analysis showed that in Eremurus root gum, the ratio of glucose to mannose was 1.1 to 1 and belonged to the glucomannan family.