Hydrothermal liquefaction of three kinds of starches into reducing sugars

Starch is the most important component of food waste. Rice, potato and sweet potato starches were selected to study the transformation of starch to reducing sugars by hydrothermal liquefaction in subcritical water. Results of morphological appearance, X-ray diffraction and thermogravimetric analysis showed that the three kinds of starches had different structural properties. The effects of reaction temperature and time on the yields of glucose, fructose and maltose were studied and the maximum yields of total reducing sugars observed were 15%, 30% and 33%, respectively. The effect of microwave heating, in comparison to conventional method of heating, on the product yield, was also studied. Results showed that microwave can effectively reduce the temperature required for the reaction. (C) 2015 Elsevier Ltd. All rights reserved.