Flavonols in fresh and processed Brazilian fruits

Flavonols (myricetin, quercetin and kaempferol) and flavones (luteolin and apigenin) were determined in Brazilian fruits, using a previously optimized and validated HPLC method. The flavonoids investigated were not detected in three cultivars each of mango and papaya. Quercetin was found in all the other fruits, the mean values varying from 0.3 mg/100 g in orange cultivar Pêra to 7.5 mg/100 g in apple cultivar Fuji. Kaempferol was encountered in strawberry (0.7–0.9 mg/100 g), acerola (0.9–1.2 mg/100 g), pitanga (0.4 mg/100 g) and cashew-apple (<LQ–0.3 mg/100 g). Myricetin was detected only in pitanga (3.1–3.7 mg/100 g) and cashew-apple (2.0 mg/100 g). The best sources of flavonols among the fruits investigated were pitanga, cashew-apple, acerola and apple, the first three being analyzed for the first time. Luteolin and apigenin were not detected in any of the fruits. The processed products (ready-to-drink juice, concentrated juice, frozen pulp) of acerola, cashew-apple and pitanga had appreciably lower flavonol levels than the unprocessed fruit, indicating losses during processing. Comparison with published data on apple, orange, strawberry and fig shows the need for interlaboratory evaluation of the analytical methodology and more analyses to obtain cultivar-specific data.