Analysis of soils, grapes, and wines for Sr isotope characterisation in Diqing Tibetan Autonomous Prefecture (China) and combining multiple elements for wine geographical traceability purposes

Abstract

Determining the origin and authenticity of wine is a matter of rising interest among consumers and industry standards. The strontium isotopic ratio is regarded as an efficient technique for wine tracing. This study presents an assessment of the Sr isotope value in different matrices, including soil, grapes, and wine. Strontium isotopic maps were built using measured data. Diqing soil isotope ratios ranged between 0.714010 and 0.721999, and grape and wine isotope ratios ranged between 0.710029 and 0.718137, and 0.709508 and 0.718372, respectively. A high correlation was found between the Sr isotope ratios between of grapes and wines (R2 = 0.945), and a weak correlation was found between soil and grapes (R2 = 0.187). In general, the 87Sr/86Sr ratios of Diqing wine have a different range from those of wine from other countries. Compared to carbon isotope values, the oxygen isotope values have a wide diversity in wine from different regions. Elemental fingerprinting, light and heavy isotopes combined with discriminant analysis (DA) and random forest (RF) supported a relatively small wine geographical origin more effectively than the isotopes. This study is the first to focus on the Sr isotopes in different matrices (soil, grapes, and wine) from China and provides a data reference for tracing the provenance of wine.