NMR-based quantitative component analysis and geographical origin identification of China's sweet orange

Sweet oranges with distinguished origin label have been becoming a fraud target by confusing or hiding origins. In this study, high-resolution nuclear magnetic resonance (NMR) spectroscopy in combination with chemo-metrics was used to discriminate the geographical origins of China's sweet oranges from four main producing regions (Hunan, Hubei, Sichuan and Guangxi). Sixty-two components, including various saccharides, amino acids, organic acids, alcohols, ketone, flavanones and other compounds, were identified and quantified via their 1H NMR spectra, and the producing region-specific geographical indication components of China's sweet orange were further screened out. The sweet oranges in Hubei show favorable antioxidant properties due to their rich phenolic compounds, and those in Sichuan show rich and fresh flavors due to their wealthy amino acids. Our results are readily available for nutritional recommendation in human consumption, and helpful to distinguish the geographical origin of sweet oranges based on their nutritional characteristics especially geographical indication markers.