Ja. Manthey et K. Grohmann, CONCENTRATIONS OF HESPERIDIN AND OTHER ORANGE PEEL FLAVONOIDS IN CITRUS PROCESSING BY-PRODUCTS, Journal of agricultural and food chemistry, 44(3), 1996, pp. 811-814
The concentrations of flavonoids were measured in the peel of differen
t orange (Citrus sinensis L.) varieties and compared to the distributi
ons of flavonoids in the byproducts of orange processing. While the fl
avanone glycoside hesperidin was the main flavonoid in peel, precipita
tion of this compound during processing resulted in dramatic losses in
hesperidin in filtered peel juice and filtered molasses. Yet, hesperi
din occurred at very high levels in dimethyl sulfoxide extracts of unf
iltered molasses (5718 ppm) and in the centrifuged insoluble solids of
orange peel molasses (65 642 ppm). The polymethoxylated flavone aglyc
ons were the only flavonoids in cold-pressed orange peel oil. These co
mpounds also occurred in high concentrations in light-density oil soli
ds and in commercial wax isolated from the cold-pressed peel oil. Thus
, the different citrus peel byproducts are selectively enriched with h
igh concentrations of different groups of flavonoid compounds.