Geographical origin assessment of orange juices by comparison of free aminoacids distribution

Scientific research nowadays makes considerable efforts for the setting of methods for the assessment of the geographical origin of food products. Very few studies have focused on orange juices, aiming at differentiating the origin of samples coming from very far areas of the world, while no research has attempted to find suitable markers able to ascertain the geographical origin of orange juices produced in neighbouring regions, such as those of south Italy, where more than 90% of the entire Italian production is concentrated. Past studies showed that the distribution of hydroxycinnamic acids in juices is effective for the origin assessment of blood orange varieties, but unsuitable for blonde ones. In the present, we have assessed and discussed the distribution of free aminoacids in orange juices. Seventy samples of the blood and blonde varieties were collected from different citrus farms located in Sicily and Calabria throughout the season 2007-2008. Nineteen aminoacids were determined, subject to prior derivatization, by HPLC with fluorimetric detector. Aminoacids were quantified by external calibration and expressed as mmol L-1 and experimental data were elaborated by statistical analysis. The total free aminoacid content, as well as the level of proline, arginine, aspartic acid, asparagine, serine and glycine can be considered as a markers of geographic origin, contributing to sharply discriminate blonde Sicilian orange varieties from Calabrian ones.