Preliminary study on distinguishing commercial orange juices based on chemical composition analysis at the laboratory scale

Tóm tắt

Orange juice is among the most consumed fruit juices worldwide, valued for its nutritional and sensory qualities. However, due to its high economic value, orange juice is also one of the most vulnerable commodities to adulteration, particularly through dilution or substitution with cheaper ingredients. This study aimed to differentiate between natural and commercial orange juice and to evaluate the ability to detect adulteration by dilution with sucrose and citric acid solutions using multivariate statistical approaches. A total of 50 samples, including fresh-squeezed orange juice, commercial juices, and artificially adulterated juices at different levels (10%, 20%, 30%, 50%, and 90%), were analyzed for organic acid composition (oxalic acid, malic acid, ascorbic acid, citric acid, and furmaric acid), flavonoids (hesperidin, narirutin) analyzed by HPLC-PDA and sugars (fructose, glucose, and sucrose) analyzed by HPLC-RID. Principal Component Analysis (PCA) was first applied to reduce data dimensionality and to identify major compounds contributing to the variation among samples. Subsequently, Discriminant Analysis based on PCA scores (PCA-DA) was used for classification and model validation. The results showed that PCA successfully separated natural juices from commercial ones, with citric acid, glucose, fructose, hesperidin, and narirutin being the main discriminant markers. For the adulterated juice experiment, PCA-DA achieved clear separation of groups, with 100% correct classification when three principal components were included in the model. These findings confirm that combining chemical profiling with PCA and PCA-DA is a reliable and efficient approach for authenticity testing of orange juice. The method provides a promising analytical tool for quality control laboratories and regulatory agencies to combat economically motivated adulteration in fruit juices.