1H‐NMR Based Metabolomics Profiling of Citrus Juices Produced in Veracruz, México

This study describes the H-1-NMR-based metabolomics profiling of juices from citrus fruits harvested in the state of Veracruz, Mexico. The hydrophilic profile of commercial lemons (Agrio and Persian), tangerines (Fremont and Monica), oranges (Valencia and Washington Navel), and grapefruits (Red Ruby and Rio Red) was determined. According to our results, 35 metabolites were identified in the H-1-NMR profiling. The statistical differences obtained by PCA and OPLS-DA revealed that specific amino acids, sugars, and organic acids were differential metabolites in the species and cultivars studied. High endogenous levels of sucrose (10-190mM), alpha -glucose, beta -glucose (alpha- and beta -isomers, 40-205mm), and fructose (36-170mm) were detected in the juices of grapefruits, oranges, and tangerines, whereas citric acid (40-530mm) was the principal organic acid in the juices of lemons. To calculate the specific amounts of metabolites from these species and their cultivars, the results were finely analyzed using the qNMR method. According to these calculations, Valencia oranges had the highest concentration of ascorbic acid (>2mm). The described H-1-NMR method is highly reproducible, inexpensive, and highly robust in comparison to other analytical methods used to determine the hydrophilic profile of citrus juices.