Effects of pectolytic enzymes on selected phenolic compounds in strawberry and raspberry juices

Abstract

To evaluate the effect of commercial pectolytic enzymes on the content of phenolic compounds (anthocyanins, flavonols and ellagic acids), strawberry and raspberry juices under enzymatic pectinase treatment were analyzed using High Performance Liquid Chromatography (HPLC) with Spectral Array Detection (SAD). Each fruit had a distinctive phenolic pattern which enabled identification and characterization. The stability of phenolic compounds during processing was monitored at 2, 4 and 6 h. The use of commercial pectinases modified the composition of phenolic compounds in relation of the fruits and the time considered. At 6 h, a loss of anthocyanins (−20%) present in raspberry juice was observed when Pectinex® BE 3-L, Rohapect® B1L, Rohament® MAX and Pectinex™ 3XL were used. This result confirmed the hypothesis of a β-glycosidase activity present into commercial pectinase. On the other hand, in strawberry treated samples the ellagic acids concentration always increased (up to 19 mg l −1 with Pectinase™ LM, at 6 h) while flavonols content decreased (−35% with Pectinase™ LM, at 6 h). Rohapect® MB was the only enzyme able to considerably increase the content of total quercetin derivatives in raspberry (36 mg l −1).