A Comprehensive Study of Anthocyanins in Two Fungal-Resistant Grape Varieties, Blueberry and Raspberry, by High-Resolution Mass Spectrometry.

Direct-infusion ESI/IT-MS/MS was previously employed to characterize grape anthocyanins that share the same nominal mass but differ in elemental composition. Subsequently, Q-TOF coupled with LC-Chip enabled the complete anthocyanin fingerprint of a single sample to be obtained in under 5 min. In this study, a comprehensive UHPLC/Q-TOF investigation of anthocyanins in three red-berry fruits (blueberry, raspberry, and two fungal-resistant red grape varieties) was performed. In total, 35 anthocyanins were identified. Only two were found in all three fruits, Cy and Pn 3-O-hexosides. The grape berries exhibit high levels of diglucosides, while only raspberries contain Pg derivatives and several di- and trisaccharide anthocyanins. Blueberry uniquely accumulated Pn-malonylhexoside and arabinosyl anthocyanins, and a difference between the two species was found, as cv Biloxi (southern highbush) contained acetyl- and p-coumaroyl glucosides not found in cv Titan (rabbiteye), alongside a preponderance of B-ring tri-substituted anthocyanins. Additionally, in blueberry two isobaric anthocyanins (Pn-hexoside and Mv-arabinoside, MF C22H23O11) were characterized. Sophoroside and rutinoside anthocyanins were found only in the raspberry, where Pn-hexosyl-rutinoside, Cy-3-hexosyl-sophoroside, and a Cy-rutinoside isomer were characterized for the first time. Findings of the study increase the knowledge on these varieties as potential sources of nutraceuticals and natural colorants, also expanding the HR-MS/MS dataset beneficial for their characterization in other fruit varieties.