Approach to the content of total extractable phenolic compounds from different food samples by comparison of chromatographic and spectrophotometric methods Original Research Article

A new approach to the error sources in the spectrophotometric determination of total phenols in foods has been performed. The choice of the suitable phenolic standard and the influence of sugars and proteins as interfering compounds were carefully studied. The results obtained by the spectrophotometric method were compared with those found from the chromatographic method which was taken as reference method because it was free of interferences. The spectrophotometric method overestimates the phenolic content except in some fruit samples with a high polyphenolic content. Sugars did not show interference whereas protein showed a high influence on the total phenols at the concentration ranges found in the extracts. In green bean samples both methods gave the same total phenols when the interference was masked. This fact could constitute an useful way to find the real content of phenolics in foods.