Antioxidant activity and phenolic composition in pomegranate (Punica granatum L.) genotypes from south Italy by UHPLC-Orbitrap-MS approach.

Abstract

Pomegranate fruits are a rich source of polyphenols with numerous health-promoting effects. Pomegranate juices of five genotypes ('Mollar', 'Kingdom', 'Dente di Cavallo', and two old populations 'Francofonte' and 'Santa Tecla') were evaluated regarding anthocyanin and non-anthocyanin phenolic contents using ultrahigh performance liquid chromatography (UHPLC)-Orbitrap-mass spectrometry (MS). Moreover, total antioxidant activity (TAA) was evaluated using a 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assay. Twenty-three phenolic compounds were identified. Cyanidin-3,5-O-diglucoside and pelargonidin-3,5-O-diglucoside were the most representative anthocyanins in all genotypes; the Santa Tecla population had the highest content of these anthocyanins, 97.64 mg L-1 and 40.29 mg L-1 respectively. In the Francofonte population, ferulic acid hexoside was the most abundant compound (391.18 mg L-1 ). TAA values ranged between 221.5 and 36.73 µmol Trolox equivalents/100 mL of juice. A high TAA value was recorded for the Santa Tecla pomegranate population. The UHPLC-Orbitrap-MS approach was employed for the first time to identify the phenolic compound profiling in five pomegranate genotypes. TAA was analysed using an ABTS assay, and the results showed a significant variability in nutraceutical potential of the pomegranate genotypes studied. The inclusion of phenolic information in the linear discriminant analysis allowed very good discriminations among genotypes to be obtained. © 2018 Society of Chemical Industry.