Authenticity of 100% orange juice in the Czech market in 1996–2001

Commercial orange juices samples obtained from the Czech market were analysed in the years 1996-2001. The quality and authenticity of samples was evaluated according to the Code of Practice of AIJN (selected main analytical criteria were followed - K + , Na + , Ca 2 + , Mg 2 + , citric, isocitric and malic acid, citric acid/isocitric acid ratio, glucose, fructose, saccharose, sorbitol, formol number, flavonoid glycosides - according to Davis and HPLC procedure, refractive index and other). The approach of producers to the quality and authenticity of juices developed during the years of observation. The main cases of adulteration in 1996 were as follows: (i) lower fruit content in juice, (ii) massive addition of sugars masked with addition of citric acid, (iii) several examples of "synthetic" orange juice were found. In the subsequent years the authenticity slightly improved, the main problems in 2000/ 2001 were: (i) lower refractive index, (ii) pulp wash addition, (iii) lower quality of water used for juice reconstitution, (iv) undeclared addition of sugar. The deviations were found not only in the case of the juices of Czech producers, but also in several discount and low-end products of foreign producers. Possible ways of improving the quality and authenticity are discussed (e.g. the preparation of a Czech National Standard taking over the requirements for juices and nectars according to the Code of Practice of the AIJN, Participation in the European Quality Control System [EQCS], etc.).