Differentiation of intermediate products (concentrates and purées) from the fruit industry by means of phenolic content

Abstract

 Concentrates and purées are intermediate products in the manufacture of commercial fruit juices. In this paper, the phenolic content [total polyphenols (TP), ortho-diphenols (ORT) and catechins (CAT)] in a large number of concentrates and purées from apple and peach fruits has been determined. The relationships TP/ORT, TP/CAT and ORT/CAT have also been calculated. TP content was found to be significantly higher in the concentrates than in the respective purées whereas CAT content was significantly higher in the purée. ORT was found to be higher in purées than in apple concentrates, but the opposite was observed for peaches. The relationships TP/ORT, TP/CAT and ORT/CAT were higher for the concentrates than for the respective purées. In addition, values for ORT/CAT were higher for the peach products than for the respective apple products. The results show that these phenolic compound measurements enable differentiation between concentrates and purées, as well as between the fruit juices produced from them. The main advantage of measurements of total phenolic compounds is that they are easy to perform in a conventional laboratory, which makes them suitable for routine analysis.