Biodynamic, organic and integrated agriculture effects on cv. Italia table grapes juice, over a 3-year period experiment: an 1H NMR spectroscopy-based metabolomics study

Background The new trend demanding for "natural" agri-food products has encouraged the application of more sustainable and eco-friendly farming methods, which limit or avoid the use of synthetic chemicals. This approach is increasing in viticulture, one of the sectors with the highest commercial value since grapes and derived products are largely consumed foodstuffs, with appreciated nutritional and sensory features. In this work, H-1 Nuclear Magnetic Resonance spectroscopy (H-1 NMR) was applied for the metabolic profiling of cv. Italia table grapes samples, from the same origin area, cultivated with different treatments (biodynamic, organic and integrated) and collected in three subsequent vintages. Multivariate statistical analysis was performed on NMR-data with the aim of comprehensively researching the possible influences on metabolites due to the use of diverse agricultural practices. Results Both inter-annual variability (2020, 2021 and 2022 vintages) and different vineyard treatments (biodynamic, organic and integrated) resulted as significant drivers for samples differentiation in the preliminary unsupervised analysis of the (H-1 NMR spectra derived) metabolic profile data. Nevertheless, supervised data analyses showed that inter-vineyards variability, due to application of diverse farming methods, had a comparable discriminating effect with respect to harvesting years. Ethanol, sugars (as alpha-/beta-glucose), organic acids (as malate) and amino acids (as arginine, leucine, glutamine) resulted the most viticultural practices-dependent metabolites. Interestingly, results from pairwise comparisons between treatments indicated the biodynamic samples with respect to the organic ones as the best-observed differentiation. This was followed by the biodynamic vs integrated and organic vs integrated samples comparisons, in decreasing discrimination order, as confirmed by the descriptiveness and predictive ability parameters of the corresponding pairwise OPLS-DA models. Conclusions Results highlighted that metabolites' composition in cv. Italia table grapes juice is significantly affected by the use of different kinds of vineyard managements (biodynamic, organic and integrated, here investigated). Metabolomics study, here employing H-1 NMR spectroscopy combined with multivariate statistical analysis, offers powerful tools to elucidate the metabolic differences among classes of samples.