A simple and feasible approach to purify konjac glucomannan from konjac flour – Temperature effect

•A simple method is developed by phase separation triggered by temperature.•Impurities are removed through magnified solubility differences.•Temperature combined with ethanol-washing is studied.•Physicochemical properties and purity of KGM could be controlled by temperature. A simple one-step purification process was provided to extract KGM from KF by phase separation. The results showed that appropriate temperature control was a key factor and the products were inodorous, colourless and of high purity at the optimal temperature 68°C. In this purification, soluble sugar and starch of extracted KGM were nearly clearly reduced and up to 95%, 80% (T68) of protein and ash were removed, respectively as compared with KF. Odour and transparency were improved 4 ranks and 30%, respectively. Besides, the ηapp reached 42.30Pas and increased by 93.55% as compared, which could stay at a steady level for a week. Furthermore, morphology of extracted KGM displayed regular lamellar and wrinkling distribution for removed impurities. The temperature-controlled method not only enriches the knowledge of KGM purification but also has the potential to broaden the application of KGM.