Determination of Phlorin as Peel Marker in Orange (Citrus sinensis) Fruits and Juices

Phlorin (3,5-dihydroxyphenyl β- d -glucopyranoside), an orange peel marker, has been isolated from orange ( Citrus sinensis ) fruits using C-18 reversed-phase column chromatography and the structural formula confirmed by 1 H and 13 C NMR spectroscopy and mass spectrometry. Aqueous extracts of orange peel were followed during more than 2 days at two temperatures, showing increasing content of phlorin in water following time. The phlorin content was determined in various parts of two orange varieties, Navel Late from Spain and Valencia from Brazil. The range of phlorin was only 10−14 mg·L - 1 in juice but was in a higher concentration in albedo (800−1000 ppm). Keywords: Authenticity; peel marker; phlorin; 3,5-dihydroxyphenyl β- d -glucopyranoside (R.N. 28217-60-9); sweet orange; juice quality; HPLC; NMR; MS