The determination of the carbohydrate content of environmental and food samples, performed by spectroscopic and chromatographic methods, needs a preliminary hydrolysis which converts polysaccharides into monosaccharides prior to the analytical measurement. In this paper, a modified procedure of the ultrasound-assisted method for the determination of total carbohydrates, published by the same authors in a previous paper, is presented and discussed. The modified procedure represents an improvement with respect to the previous one because it shortens the hydrolysis time and the colorimetric determination times through the use of two acid media (formic and acetic acid) that also allows quantitative recoveries of total carbohydrates from food and environmental samples.