Control of Authenticity of Fruit Juices by Isotopic Analysis

Abstract

Abstract In order to differentiate a natural fruit juice from a dilute concentrate, we have investigated the isotopic composition of their water. We have chosen the stable isotopes deuterium and 18O. The water of orange juices is strongly enriched in heavy isotopes, as compared to rain water. This enrichment is much lower for French apple juices and seems to be due to evapotranspiration. The relationship between deuterium and 18O observed for meteoric water is modified in the fruits. If a fruit juice is concentrated and then rediluted with natural water, the isotopic composition of its water would be very similar to the original deuterium and 18O content of the dilution water. Isotopic analysis allows a very confident distinction between natural fruit juices and reconstituted juices.