Determination of quality and adulteration of tequila through the use of surface plasmon resonance

Design of a Novel Auxiliary Diagnostic Test for the Determination of Authenticity of Tequila 100% Agave Silver Class Based on Chemometrics Analysis of the Isotopic Fingerprint of the Beverage

The present research shows a robust isotopic ratio characterization of Carbon-13 (δ¹³C_VPDB) in congeneric compounds such as methanol, n-propanol, isoamyl alcohol, ethyl lactate, ethyl acetate, ethanol, and acetaldehyde in representative samples (n = 69) of Tequila 100% agave silver class (TSC), employing gas chromatography/combustion/isotope-ratio mass spectrometry (GC/C/IRMS). From the information obtained, the construction of a radial plot attributable to the isotopic fingerprint of TSC was achieved. With this information, a diagnostic test was designed to determine the authenticity of TSC, comparing alcoholic beverages from other agave species as non-authentic samples. The sensitivity of the test was 94.2%; the specificity was 83.3%. Additionally, non-authentic samples were analyzed that meet all the criteria established in the regulations. The results obtained show that the GC/C/IRMS analytical technique and designed diagnostic test are useful as auxiliary parameters to determine the authenticity of the beverage, thus managing to determine the adulteration or falsification of the product.

A critical review on the assessment of the quality and authenticity of Tequila by different analytical techniques: Recent advances and perspectives

Currently, the authenticity and traceability of Tequila are determined in an inspection process carried out by the Tequila Regulatory Council. However, in recent years, the authorities have seized illegal alcoholic products that are marketed as Tequila without being so, making it necessary to strengthen the current methods of detecting counterfeiting and/or adulteration. Therefore, it is important to establish a review of the current analytical techniques that have been proposed to solve this problem. In this review, emphasis is placed on the analysis of the analytical techniques that have been used to consolidate a profile of authenticity and quality in Tequila, thus highlighting new auxiliary analytical techniques to the current verification process, establishing future validation opportunities in terms of international quality control. The use of isotopic ratios stands out as the most robust technique because it establishes the type of sugar source used and the maturation time of the manufacturing process.

Recent advances in Surface Plasmon Resonance (SPR) biosensors for food analysis: a review

Food safety is the prime area of concern that builds trust. With the prevailing advancements, it has become facile to ensure safety in almost all aspects. Technology has grown from tedious lab techniques to modern chromatographic techniques and immunoassays, progressed with more precise and rapid sensing through the advent of Biosensors. Biosensors provide an automated technology by presenting superfast, nondestructive and cost-effective detection in food analysis. SPR biosensor is an optical biosensor known for its versatility and has wider applications in food testing and analysis. It has an optical system for excitation and interrogation of surface plasmons, and a biomolecular recognition element to detect and seize the target analyte present in a sample. The optical signal detects the binding analyte, on the recognition element, which results in a change in refractive index at the surface and modifies the surface plasmons' propagation constant. SPR aids in label-free detection of various components such as adulterants, antibiotics, biomolecules, genetically modified foods, pesticides, insecticides, herbicides, microorganisms and microbial toxins in food and assures safety. The distinct advancements of SPR in food analysis have been found and discussed. The review also provides knowledge on the advantages and the key challenges encountered by SPR.

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

Isotopic ratios of δ¹³C_VPDB and δ¹⁸O_VSMOW have been used as an additional parameter to ensure the authenticity of the aging time of 100% agave tequila. For this purpose, 120 samples were isotopically analyzed (40 silver class, 40 aged class, and 40 extra-aged classes). The samples were obtained through a stratified sampling by proportional allocation, considering tequila producers from the main different regions of Jalisco, Mexico (Valles 41%, Altos Sur 31%, Cienega 16%, and Centro 12%). The results showed that the δ¹³C_VPDB was found in an average of −12.85 ‰ for all the analyzed beverages, with no significant difference between them. Since for all the tested samples the Agave tequilana Weber blue variety was used as source of sugar to obtain alcohol, those results were foreseeable, and confirm the origin of the sugar source. Instead, the results for δ¹⁸O_VSMOW showed a positive slope linear trend for the aging time (silver class 19.52‰, aged class 20.54‰, extra-aged class 21.45‰), which is associated with the maturation process, there are oxidation reactions that add congeneric compounds to the beverage, these can be used as tracers for the authenticity of the aging time. Additionally, the experimental data showed homogeneity in the beverages regardless of the production region, evidencing the tequila industry’s high-quality standards. However, a particular case occurs with the δ¹⁸O_VSMOW data for the silver class samples, in which a clear trend is noted with the altitude of the region of origin; therefore, this information suggests that this analytical parameter could be useful to authenticate the regional origin of beverage.

A technique based on droplet evaporation to recognize alcoholic drinks

Chromatography is, at present, the most used technique to determine the purity of alcoholic drinks. This involves a careful separation of the components of the liquid elements. However, since this technique requires sophisticated instrumentation, there are alternative techniques such as conductivity measurements and UV-Vis and infrared spectrometries. We report here a method based on salt-induced crystallization patterns formed during the evaporation of alcoholic drops. We found that droplets of different samples form different structures upon drying, which we characterize by their radial density profiles. We prove that using the dried deposit of a spirit as a control sample, our method allows us to differentiate between pure and adulterated drinks. As a proof of concept, we study tequila.

Detection of aromatic compounds in tequila through the use of surface plasmon resonance

For an expert nose, the aroma of a beverage is a fingerprint that can be used to certify its authenticity, distinguish between distillation processes, or even identify the raw material used to fabricate it. In this work, we propose a simple, automatic, and repeatable optical method, which can be used as a first and quick test to authenticate tequila samples. This method is based on the measurement of beam intensity changes, using the surface plasmon resonance technique, operating at a fixed angle. We observed that each tequila, depending on the alcohol content and aging process, produces a specific change in measured intensity level.