IMPROVING FRUIT JUICE ORIGIN ASSIGNMENT BY COMBINED CARBON AND NITROGEN ISOTOPE RATIO DETERMINATION IN PULPS

The combination of the relative abundances of carbon and nitrogen isot opes (delta(13)C- and delta(15)N- values) in fruit juice pulps led to characteristic clusters, on the basis of which regional origin assignm ents of citrus juices were possible, which would not have been attaine d on the basis of only one of these parameters. Thus, while the delta( 13)C-values of juice pulps from Italy partially overlapped with those from Brazil, the delta(15)N- values permitted an origin assignment. Fi rst attempts to extend this multi-isotope analysis to a multi-compound N-15 analysis, by correlating the delta(15)N-values of fruit juice pu lps to those of free amino acids, were promising. The results obtained were in line with general observation on N-15 abundances and biochemi cal correlations of secondary plant products.