Effect of Age of Agave tequilana Weber Blue Variety on Quality and Authenticity Parameters for the Tequila 100% Agave Silver Class: Evaluation at the Industrial Scale Level

Abstract

Due to the oversupply and scarcity cycles of the Agave tequilana Weber blue variety, the effect of agave age (harvested in 4, 5, and 6 years) as raw material for the tequila 100% agave silver class was studied for each stage in a full-scale (industrial) process. Harvested plants showed differences in their morphological characteristics that affected the amount of juice; this had an impact in the fermentation stage since must composition was modified in the nitrogen content and juice/exudate ratio. This was noticed due to an increase in the production of higher alcohols attributed to the odd-chain fatty of the exudate, which affects n-propanol production. The characterization of the final product showed the feasibility to use agaves (less than 7 years) to produce the Tequila 100% agave silver class and to comply with the quality criteria. Furthermore, the final product was analyzed with the gas chromatography-isotope ratio mass-spectrometry technique to determine its authenticity. The δ13CVPDB isotopic parameter (−13.40‰ in average) values show the type of plant used as a raw material for ethanol production, while the δ18OVSMOW (20.52‰ in average) isotopic parameter can be helpful in corroborating and ensuring the traceability of the product and the geographical location of the beverage production.

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

“…Consequently, these compounds have higher values in their variation coefficients (>20%), and this effect its related to Tequila 100% agave production processes. It is proposed that these variations could be due to the fermentation and distillation stages, due to the fact that each company possesses yeast strains and specific operational parameters to grant unique organoleptic properties to their products [ 32 , 33 , 34 , 35 , 36 , 37 ]. These differences can also be observed when comparing the values of Tequila against alcoholic beverages produced from other agave species.…”

“…The proposal for the δ 13 C VPDB values is more negative in this congener due to the operating conditions in the fermentation stage. It has been evidenced that several operation conditions can affect the physicochemical profile of the beverages, such as pH, temperature, nutrients, and kind of yeast [ 11 , 32 , 42 , 44 ]; among them, the type of yeast stands out, which has been shown to be the one that has the most influence in producing this congener [ 45 ]. In such a way, the production of ethyl acetate can be related due to the type of yeast and plants used, due to the fact that there is a complex amount of nutrients that enhance fermentation according to its concentration, such as sugars, amino acids, fatty acids, and micronutrients, which impact the fermentation process.…”

“…Additionally, the presence of certain compounds, such as Maillard reactions, which are obtained from various molecules, such as amino acids or proteins, and reducing carbohydrates also had an impact [ 51 ]. Finally, the alterations observed in the δ 13 C VPDB values from the molecule of n-propanol can be related to modifications in the production of this beverage, which can be by the use of raw material with less age, such as agaves from 4 to 6 years, in the Tequila production, the use of which modifies the juice/exudate ratio in the fermentation tanks, which favors a metabolic route that produces this alcohol [ 32 ]. For this reason, the score associated in the diagnostic test to these compounds is less to evaluate authenticity in the beverage.…”

The price of agave in Mexican states holding Designation of Origin of Tequila status, and its systematic depreciation over the forthcoming decade (2000-2031)

“…The tequila industry seeks to meet the sustained growth in demand for tequila without transferring the benefits of this increased income to the primary producers of agave. From this perspective, we can understand the significance of the "historical moment" that saw the publication of the investigation "Effect of the age of the tequilana agave Weber Blue Variety on the quality and authenticity parameters for 100% Agave Silver Class tequila: Industrial scale evaluation" (Acosta Salazar et al, 2021) that demonstrated that processing "young agave" plants, just 3 or 4 years old (previously 6 years), does not affect its usefulness. This shift to the use of young agave does not entail any economic benefit for the primary producer 32 either (the cultivation cycle of the blue agave plant from planting to harvesting is reduced by up to 50%, and therefore so are farmers' costs), but does contribute significantly to the increase in its supply, further depressing its value.…”

“…Acosta Salazar et al (2021) describes the severe problems suffered by the supply chain of the tequila production process as a result of the length of time the agave plant takes to reach maturity and be ready for use (six years). He points out that "the transition between scarcity and oversupply" has been a cyclical driver of falls or steep increases in its value.…”