Changes of Some Flavonoids in the Peel of Late Maturing Citrus during Maturation

Eleven flavonoids, including rutin, naringin, hesperidin, neohesperidin, quercetin, naringenin, kaempferol, hesperetin, nobiletin, 3,5,6,7,8,3',4'-methoxylated flavone, tangeretin in the peel of late maturing citrus fruit species of Mucott (smith tangerine), Singamha (C. natsudaidai), Sambogam (C. sulcata), Hongpalsak (C. hassaku), Seminol (Dancy tangerine), Jawdung (C. aurantium) harvested during from August to December were analyzed with HPLC. The mobile phase consisted of water, acetonitrile with 0.5% acetic acid. Wavelength in UV detector was determined at 254 nm. Naringin, neohesperidin content in the peel of Jawdung harvested at the early stage of maturation were 34.02 mg/g, 13.68 mg/g, respectively,, it was highest among the tested citrus fruits. Hesperidin content in the peel of Mucott harvested at the early stage of maturation was 12.48 mg/g. Rutin content of Sambogam harvested at the early stage of maturation was 5.13 mg/g. Quercetin, naringein, kaempferol, nobiletin, 3,5,6,7,8,3',4'-methoxylated flavone flavonoids were in trace. Flavonoid contents of Singamha, Sambogam, Jawdung were high in the peel of fruits at the early stage of maturation, after which time they decreased rapidly.