Underestimation of carbohydrates by sugar alcohols in classical anthrone-based colorimetric techniques compromises insect metabolic and energetic studies

Abstract

Physiologically based metabolic studies usually search for easy, sensitive, and cheap techniques to rapidly estimate biological parameters such as nutrient content. Colorimetric methods to estimate carbohydrates have been extensively used (over 120,000 references). However, sugar alcohols are underestimated under conventionally used analytical conditions, in particular if using the popular van Handel method. This may lead to misinterpretations of sugar implications in biological systems. We determined the anthrone reaction with various sugar alcohols and non-alcohols individually under standard conditions (Van Handel 1985). We then manipulated the proportion of either sugar alcohols or non-alcohols in three different sugar mixtures in order to estimate the impact on the total sugar estimation. In the case of a mixture with over 50% of sugar alcohols, total sugars are underestimated by 50% when using glucose as standard.