Total anthocyanin, flavonoid, polyphenol and tannin contents of seven pomegranate cultivars grown in Iran.

BACKGROUND: Pomegranates are healthy fruits rich in bioactive phytochemicals and widely consumed in  the human diet. This study was designed to assess their physico-chemical properties and total polyphenolic compounds, along with antioxidant and ascorbic acid concentrations of the skin and juice of seven unstudied pomegranate cultivars grown in Iran.

METHODS: Ten fruits of each of seven selected cultivars were picked. Methanolic extracts from the fruit skins as well as juices were subjected to an evaluation of their physico-chemical properties and phenolic content.

RESULTS: From the pomegranate cultivars studied, the highest juice concentration was measured in ‘Zagh- -e-Zabol’ (72.9 ±2.55%). The highest total soluble solids (18.79 ±1.06 oBrix) of juice, as well as the highest ascorbic acid (16.54 ±2.09 mg/100 g) and total anthocyanin content of skin [11.20 ±2.4 mg CyE (cyanidin- -3-glucoside equivalent)/L] were measured in ‘Bajestan’. Total flavonoids were more concentrated in the skin of ‘Siah-e-Zabol’ [930 ±16 mg QuE (quercetin equivalent)/L]. In the juice of ‘Rabab-e-Pust Ghermez’ and ‘Malas-e-Saveh’ the highest concentrations of phenolic compounds were recorded [1082 ±12.8 mg GaE (gal- lic acid equivalent)/L] and tannins [6.55 ±0.5 mg TaE (tannic acid equivalent)/L], respectively.

CONCLUSIONS: Significant differences were assessed between the skin and juice of the cultivars in terms of their physico-chemical properties and polyphenolic contents. The results showed higher levels of total tannins, phenolics and antioxidant activity in juice of pomegranate, whereas the skins possessed higher total flavo- noid, anthocyanin and ascorbic acid content. Further phytochemical analysis are therefore needed to identify the most representative phenylpropanoids by LC-MS (liquid chromatography coupled to mass spectrometry) and to develop novel and promising dietary supplements.