Perini M, Strojnik L, Paolini M, Camin F
Fondazione Edmund Mach, Via Edmund Mach 1, 38010 San Michele all'Adige, Italy.
Department of Environmental Sciences, Jožef Stefan Institute, 1000 Ljubljana, Slovenia.
J Agric Food Chem. 2020 Mar 18;68(11):3322-3329. doi: 10.1021/acs.jafc.9b05952. Epub 2020 Feb 19.
Since ancient times, grape must and wine have been considered one of the most sophisticated matrices and, in the last few years, the continuous rise in volumes and prices of grapes and wine has encouraged fraud and adulteration in the oenological field. One of the most common adulterations is sugar addition to grape must in the form of cane or beet sugar or syrup coming from vegetable sources, such as cereals or fruits. Since 1990, the International Organisation of Vine and Wine (OIV) has issued specific official isotopic methods to fight against this practice, but they are not always effective. With the aim to develop a new method able to identify sugar addition, we compared the δC value of sugar extracted from grape must analyzed by elemental analyzer/isotope ratio mass spectrometry (EA-IRMS) to the δC value of proline analyzed by gas chromatography-combustion isotope ratio mass spectrometry (GC-C-IRMS), after extraction and derivatization. δC and δN of proline have also been tested as potential geographical markers. In addition, the carbon isotopic composition of two characteristic grape must sugars (- and -inositols) was measured by GC-C-IRMS, after derivatization, to identify the illegal correction of their concentration. On the basis of the obtained results we can conclude that the compound-specific isotope analysis represents a novel analytical tool to support and improve certification and control procedures.
自古以来，葡萄汁和葡萄酒就被认为是最复杂的基质之一，在过去几年里，葡萄和葡萄酒产量与价格的持续上涨助长了酿酒领域的欺诈和掺假行为。最常见的掺假行为之一是以蔗糖、甜菜糖或来自谷物或水果等植物来源的糖浆形式向葡萄汁中添加糖分。自1990年以来，国际葡萄与葡萄酒组织（OIV）发布了特定的官方同位素方法来打击这种行为，但这些方法并非总是有效。为了开发一种能够识别添加糖分的新方法，我们将通过元素分析仪/同位素比率质谱仪（EA - IRMS）分析的葡萄汁中提取的糖的δC值与经过提取和衍生化后通过气相色谱 - 燃烧同位素比率质谱仪（GC - C - IRMS）分析的脯氨酸的δC值进行了比较。脯氨酸的δC和δN也已作为潜在的地理标记进行了测试。此外，通过GC - C - IRMS在衍生化后测量了两种特征性葡萄汁糖（ - 和 - 肌醇）的碳同位素组成，以识别其浓度的非法校正。根据所得结果，我们可以得出结论，化合物特异性同位素分析是一种支持和改进认证与控制程序的新型分析工具。
