Effects of condensed tannins on anthocyanins and colour of authentic pomegranate (Punica granatum L.) juices

This study was conducted to determine the effects of condensed tannins (CT) on anthocyanins (ACNs) and colour of pomegranate juice (PJ) samples obtained from nine registered varieties in Turkey. CT-catechins (CTCs) reactive to vanillin and phloroglucinol adducts of CT contents were determined. CTC and ACN contents of PJs highly depended on variety (p < 0.01), and ranged from 31 to 155 mg/L juice and from 47 to 405 mg/L juice, respectively. As catechin–phloroglucinol content increased, ACN content also increased (r = 0.866). Strong logarithmic correlation between the ratio of ACN contents to catechin–phloroglucinol contents and polymeric colour (PC) values of the samples was found (r = −0.822). When PC value of PJs was ⩾8% or ratio of ACN contents to catechin–phloroglucinol contents of PJs was ⩽2.82, ACN contents of the samples determined by spectrophotometric method were higher than those determined by HPLC.