Fruits and fruit products. Non-parametric methods for detection of adulteration of concentrated orange juice for manufacturing.

The composition of organic constituents (total sugars, reactive phenols, total amino acids, arginine, and gamma-aminobutyric acid) has been measured in a large (360 samples) selection of concentrated orange juice for manufacturing and orange pulp wash in the U.S. trade. The detection of adulteration with sugar, reducing sugars, and citric acid addition has been investigated by using non-parametric nearest neighbor classification techniques in the 4-space of log ratios of the compositions. The results show that such detection is possible with a type 1=type 2 error rate of 10% for 20% adulteration if at least 7 samples are taken. The assumptions of such samplings are discussed.