A method of making modified konjac glucomannan flour that acts a gelling agent. The method comprises mixing the flour with an alkali-alcohol solution for sufficient time and at sufficient temperature to deacetylate the glucomannan. The modified flour can then be recovered, neutralized, and milled to obtain modified konjac flour that acts a gelling agent. The gelling agent forms gels at high temperature when mixed with water and heated to above an activation temperature, and mixed for a period of time. The gels are useful in a variety of food products.