COMPARATIVE STUDY OF METHODS FOR CARBOHYDRATES ANALYSIS IN DIETETIC PRODUCTS

Abstract

Using conventional methods for carbohydrate analysis (Fehling, phenol­sulphuric acid, Somogyi-Nelson, glucose oxidase, and Roe) it was investigated the validity of these methods based on their criteria o f reliability, for different dietetic food matrices. Those analysed were dietetic jellies and chocolates of different brands and tastes, collected at a local market by the "Secretaria de Vigilância Sanitária do Paraná (Curitiba, PR, Brasil)". The phenol-sulphuric acid and the Roe methods do not require a prior hydrolysis treatment of the samples due to the presence of sulphuric and hydrochloric acids in the reaction medium, respectively. The Somogyi-Nelson and Roe methods were more influenced by the jelly matrix, and gave lower carbohydrate contents in chocolates. It was suggested the use of the phenol-sulphuric acid as an official method for carbohydrate analysis of dietetic products due to its sensitivity, precision, accuracy. It does not require a hydrolysis step, is not affected by the food matrix, and is also relativily easy to carry out.