Analytical characterization of tequila (silver class) using stable isotope analyses of C, O and atomic absorption as additional criteria to determine authenticity of beverage

Isotopic Characterization of 100% Agave Tequila (Silver, Aged and Extra-Aged Class) for Its Use as an Additional Parameter in the Determination of the Authenticity of the Beverage Maturation Time

“…It is observed that the values are in the order of −12.84 ± 0.54‰ for silver class, −12.84 ± 0.41‰ for aged class, and −12.86 ± 0.34‰ for extra-aged class ( Figure 1 a). When comparing the means of all the samples, no significant differences were detected ( p = 0.96 > 0.05), which corroborates the authenticity of the three classes of tequila analyzed since the values obtained are in the range previously reported [ 2 ]; from these results, it is possible to determine the type of plant used as a sugar source during the fermentation step. According to different authors [ 2 , 24 , 25 , 26 ] depending on the photosynthetic process to fix atmospheric CO 2 , plants are classified into three groups: (i) C3 plants that use the Calvin cycle, whose values of δ 13 C have been reported in a range of −22 to −33‰; (ii) C4 plants, that follow the Hatch Slack cycle, whose values of δ 13 C are within a range of −10 to −20‰; (iii) Crassulacean Acid Metabolism (CAM) plants which have a δ 13 C in a range of −12 to −30‰, of this group, the species that fix CO 2 at night stand out, which have a carbon delta close to 13‰ very similar to the experimental results obtained in the range between −12.0 to 13.5‰, these values can be related to the species of Agave tequilana Weber blue variety used in the sugar fermentation process.…”

“…(d) “Añejo” (extra-aged): Product which may be enhanced by mellowing in an aging process for at least one year in wood or oak recipients with V ≤ 600 L. (e) “Extra añejo” (ultra-aged): Product which may be enhanced by mellowing in an aging process for at least three years in wood or oak recipients with V ≤ 600 L. The production process is continuously regulated and verified by the Consejo Regulador del Tequila A.C. (Tequila Regulatory Council) to guarantee the consumer the authenticity and quality of the beverage, its raw materials, and the legal requirements that protect the appellation of origin. In recent years the CRT has documented counterfeit tequila cases in different parts of the world, which has led to the destruction of these products in the United States of America, Uruguay, Greece, France, Germany and Chile [ 2 ]. The economic problems caused to the industry formally established by the illegal sale of fraudulent beverages are evident and estimated in millions of pesos; however, the damage caused to the tequila brand is even more relevant since it directly affects the image of the agave tequila sector internationally, and potentially puts the consumer at risk.…”

Geographical Origin Identification of Tequila Based on Multielement and Stable Isotopes

“…Besides the carbon and oxygen isotope ratio shown Table 4, the δ 13 C experimental data are in a range of −14.29% and −12.60%. Similar results have been reported for a range of −12.1% to −13.2% [26] and a range of −11.0% to −14.0% [17], which suggests that the multielement content as well as carbon and oxygen isotope ratios of tequila varies between different geographical origins. erefore, these can be used to assist geographical origin traceability analysis.…”

“…Since it is difficult to metabolize or change them during the brewing and aging process, they can be taken as an important marker used to identify the geographical origin of tequila. It is possible to use the carbon 13 isotopic ratio (δ 13 C VPDB ), oxygen 18 isotopic ratio (δ 18 O VSMOW ), and the element content as complementary parameters of authenticity to identify tequila and tequila 100% agave (silver class) [17,18]. Using the 49 mineral elements combined with the stable isotope ratios of C, N, O, S, and Sr, Bontempo et al [19] identified the geographical origin of 10 cheese samples obtained from the Alps; the correct classification rate of the samples reached up to 94%.…”

Nuclear Magnetic Resonance Metabolomics with Double Pulsed-Field-Gradient Echo and Automatized Solvent Suppression Spectroscopy for Multivariate Data Matrix Applied in Novel Wine and Juice Discriminant Analysis

“…It has identified possible counterfeit products by monitoring the presence of specific metabolites within a sample [ 2 ]. This technique has also identified possible adulterations in coffee [ 3 , 4 ], tea bags for herbal infusions [ 5 , 6 , 7 , 8 ], vodka [ 9 , 10 ], milk and dairy products [ 11 , 12 , 13 ], honey [ 9 , 14 , 15 ], beer [ 9 , 16 ], oil [ 7 , 17 , 18 ], wine [ 2 , 19 , 20 , 21 , 22 ], juice [ 2 , 23 , 24 ]; vinegar [ 2 , 9 , 25 ], tequila [ 9 , 25 , 26 ], rum [ 9 ], and whiskey [ 9 ], amongst others. Spectroscopic and spectrometric techniques combined, in some cases, with chromatographic methods are useful to assure the food quality to avoid adulterations and fraud and determine the geographical origin of the constituent ingredients, because consumers consider this data as one of the principal quality indicators [ 27 ].…”