Solid-phase extraction and HPLC determination of .beta.-cryptoxanthin and .alpha.- and .beta.-carotene in orange juice

Abstract

A simplified method is presented to determine three important orange juice carotenoids. Nonaqueous reversed-phase (NARP) high-performance liquid chromatography (HPLC) employing acetonitrilemethylene chloride-methyl alcohol (65:25:10, v/v) and a C-18 column was used to separate /3-cryptoxanthin and a-and /3-carotene from other juice components. Detection was at 450 nm. A photodiode array detection (PDAD) system was used to obtain UV-visible spectra for chromatographic peak identification and to determine chromatographic peak purity. Methanol was used to extract the carotenoids from centrifuged juice solids. A C-18 solid-phase extraction column was used to clean up the saponified sample prior to HPLC analysis. Ratios of /3-carotene to -carotene and /3-cryptoxanthin to /3-carotene from repeated ( = 5) injections were determined with relative standard deviations of 3.3 and 2.6%, respectively. Average carotenoid ratios for Valencia orange juice were 1.08 and 2.31, respectively. Murcott juices had average carotenoid ratios of 18.1 and 5.8, respectively.

A Routine High-Performance Liquid Chromatography Method for Carotenoid Determination In Ultrafrozen Orange Juices

“…The first set included solvent systems similar to those reported by several authors and consisted in ternary mixtures of acetonitrile (in the highest proportion), methylene chloride, and methanol (in the lowest proportion) (9,22,23). When these mobile phases were employed, only carotenes and the least polar xanthophylls could be separated.…”

Review: Analysis of carotenoids in orange juice

“…Among them, isocratic methods applied to the analysis of orange juice are well represented in the literature. Fisher and Rouseff (1986) developed a solidphase extraction procedure for the determination of provitamin A carotenoids on a Zorbax C 18 column using a mixture of acetonitrile, methylene chloride and methanol (65:25:10). C 18 cartridges previously conditioned with methanol were used for the extraction of a-carotene (b,e-carotene), b-carotene and b-cryptoxanthin (b,b-caroten-3-ol).…”

“…In relation to this, it is to be considered that the final transfer of the pigments to diethyl ether may be counterproductive, as it could contain peroxides that accelerate oxidation reactions, although nowadays highpurity diethyl ether is commercially available and can be used for this purpose. Fisher and Rouseff (1986) used methanol as extractant and transferred the coloured extract to methylene chloride. The low boiling point of this solvent allows a very rapid concentration of the extract, although, on the other hand, it is reportedly a potential carcinogenic and mutagen agent, which is raising certain concern in relation to its impact on the environment due to its extensive use in the industry, so every precaution must be taken when using this solvent.…”

“…Some authors keep the reaction for a short time (Stewart, 1977a), whereas others recommend to keep the reaction overnight (Rouseff et al, 1996;Gama and Sylos, 2005). Fisher and Rouseff (1986) tested reaction times from 0.5 to 2 h and observed that 1 h was the optimum saponification time for orange juice. Experiences accomplished in our laboratory have also led us to the same conclusion, although it has also been suggested that 0.5 h may be sufficient to obtain saponified orange juice carotenoids (Corte´s et al, 2004).…”

Analysis of carotenoids in vegetable and plasma samples: A review

“…In some studies, solid-phase extraction technique has been used prior to analysis, in order to provide a better purification of the analyte (Fisher and Rouseff, 1986;Iwase, 2002).…”