Chemometrics coupled with ultraviolet spectroscopy: a tool for the analysis of variety, adulteration, quality and ageing of apple juices

Summary This study demonstrates the use of UV spectroscopy (UV) in combination with chemometrics as a simple and feasible approach for analysis of variety, adulteration, quality and ageing of apple juice. The results show that PCA‐UV is adequate to differentiate apple juice varieties and adulteration. The percentage of the adulterant can be detected by PLSR‐UV with RMSE < 0.7783% and R2 > 0.9980. For the evaluation of juice quality, PLSR‐UV (RMSE = 0.2555–2.3448; R2 = 0.7276–0.9816) is recommended for the prediction of soluble solids, ascorbic acid, total flavonoids, total sugar and reducing sugar, whilst PCR‐UV (RMSE = 0.0000–2.7426; R2 = 0.7073–1.0000) is adequate for the prediction of pH and antioxidant activity. In addition, PLSR‐UV may be used to predict the storage time with RMSE = 0.4681 day and R2 = 0.9832. Therefore, UV coupled with chemometrics has potential to be developed as a portable tool for the detection of variety, adulteration, quality and ageing of not only apple juices, but also other fruit and vegetable juices.