Comparison of Carotenoid Components between GM and non-GM Papaya

Abstract

We compared the carotenoid profile in GM papaya (Sunup) line to that of a non-GM one (Sunset). First, to identify major carotenoids in papaya, large-scale extraction was carried out with methanol. HPLC analyses of the methanol extracts revealed that both papayas mainly contained 5 pigments and no apparent difference was observed in the HPLC profiles. On the basis of LC/MS data and photodiode-array spectra, β-carotene (3), lycopene (2), β-cryptoxanthin (1), and β-cryptoxanthin myristoyl and lauroyl esters (4 and 5) were identified as major carotenoids.
It is well known that most carotenoids are labile, so a rapid analysis with precautions to avoid decomposition was developed to quantify their contents in the original fruits. Frozen samples of the fruits were sliced and a piece (about 2 g) of fruit was cut out and lyophilized. After extraction of the piece with methanol containing an anti-oxidant, BHT, the extract was further partitioned with hexane and methanol. Finally the contents of the main carotenoids in the hexane fraction were analyzed by HPLC.
The contents of total carotenoids (sum of 1∼5) and β-cryptoxanthin (1, 4 and 5) in GM papaya fruit were estimated to be 0.764±0.056 and 0.604±0.051 (μmol/g), respectively and those in non-GM fruit were 0.883±0.145 and 0.705±0.098 (μmol/g), respectively. These differences are not statistically significant.