Flavonols and Anthocyanins of Bush Butter, Dacryodes edulis (G. Don) H.J. Lam, Fruit. Changes in Their Composition during Ripening

Dacryodes edulis is a multipurpose tree presently undergoing domestication in central Africa and the countries bordering the Gulf of Guinea, the fruits of which are a good source of essential fatty acids. Polyphenols were characterized in the skin zone and in the pulp of bush butter [Dacryodes edulis (G. Don) H.J. Lam] fruits at different stages of ripeness, from unripe to soft fruits. Total polyphenols, assayed according to the Folin−Ciocalteu method, accounted for 3.0−4.2 mg/g of fresh skin, corresponding to 18.6−21.6 mg/g of defatted dry skin, higher concentrations than in the pulp, with 1.1−1.4 mg/g of fresh weight, corresponding to 5.4−12.3 mg/g of defatted dry weight. Reversed-phase high-performance liquid chromatography revealed the presence of flavonols and anthocyanins. Flavonols appeared to be the main class, with quercitrin as the main individual compound, and the highest concentrations occurred in the skin zone. Hyperin, isoquercitrin, isorhamnetin rhamnoside, and isorhamnetin hexoside were also present in relatively high amounts. Petunidin, cyanidin, and peonidin hexosides were identified by mass spectrometry. In the course of ripening, the total polyphenols as well as the major flavonols increased slightly between unripe and preripe stages and then declined gradually as ripening progressed. Anthocyanin profiles also showed a substantial change during ripening, concomitant with the color change from pink to purple. Keywords: Bush butter; Dacryodes edulis; polyphenols; quercitrin; ripening; ESI-MS