The use of stable isotopes ratios for authentication of fruit juices

摘要

The determination of the content of stable isotopes, ~(18)O and ~2H, respectively, in juice water facilitates the distinction between authentic juices and juices made from concentrates by redilution with tap water. At the same time, the detection of C_4 cane or corn-derived sugar syrups in fruit juices which are produced from C_3 fruit types is thus facilitated by the characteristic differences in ~(13)C/~(12) C,expressed as δ ~(13)C (%o) values due to photosynthetic CO_2 assimilation via the C_3-, C_4-,and crassulacean acid metabolism pathways. In this study, the quantitative determination of water added to an authentic juice, on the basis of δ~(18)0, and δ ~2H values, respectively, was successfully performed. Also, the δ ~(18)0, and δ ~2H of juice water and δ ~(13)C of the whole juice in 18 samples were also determined. The results obtained provided us with the possibility of distinguishing between authentic fruit juices and those obtained by redilution of concentrated fruit juices and the detection of C_4 type added sugar.