Identity and occurrence of certain flavonol glycosides in four varieties of pears

Abstract

The principal flavonol glycosides of Packingham pears were isolated and identified. Mass spectrometry and nuclear magnetic resonance were used to

Phenolic compounds analysis in the determination of fruit jam genuineness

“…The small amount of these substances prevented their full identification. However, these results were strongly in agreement with those found for different pear cultivare (Duggan, 1969;Spanos and Wrolstad, 1990).…”

Phenolics of apple, pear, and white grape juices and their changes with processing and storage. A review

“…Nortjé and Koeppen (1965) isolated five flavonols from Bon Chretien pears: isoquercetin, isorhamnetin 3-O-glucoside, isorhamnetin 3-O-rhamnoglucoside, isorhamnetin 3-O-rhamnogalactoside, and a fifth compound believed to be an acid-conjugated form of isorhamnetin 3-O-glucoside. Duggan (1969b) confirmed the presence of these flavonol glycosides in Packingham, Bartlett, Bose, and d'Anjou pears using mass spectrometric and NMR as identification techniques and reported the presence of quercetin 7-O-xyloside as a new compound not previously identified. A distribution of flavonols in the fruit presented by Herrmann (1976) shows that 28 µg/g of quercetin and 12 µg/g of kaempferol were found in skins and peels of Williams Christ pears.…”

Phenolics in Food and Nutraceuticals

“…Subsequently, Duggan (1969b) confirmed the presence of quercetin 3-O-glucoside in Packingham pears and detected seven additional flavonols. Of these, four were positively identified as isorhamnetin 3-O-glucoside, isorhamnetin 3-O-rutinoside, isorhamnetin 3-O-galactoside and quercetin 7-xyloside.…”