Grape Juice Quality Control by Means of H NMR Spectroscopy and Chemometric Analysis

This study shows the potential of 1 H NMR and chemometrics for quality control of grape juices. A wide range of quality assurance parameters were accessible on a single 1 H NMR experiment obtained directly from the samples, such as high amounts of ethanol. The results demonstrated the importance of storing the grape juices under refrigeration after the bottles were opened, in order to minimize fermentation, and that recommendation for storage time should be revised and should be indicated on all labels. The sterilization process of homemade samples was very efficient, making it possible to store them for long periods without the need of additives. Besides, chemometric analysis of the 1 H NMR spectra classified the best commercial grape juices closest to homemade samples, indicating that this approach can be used to determine the authenticity or adulteration of grape juice.