Search

Mezcal is a traditional alcoholic beverage in Mexico obtained from fermentation of juices, coming from mature agave pineapples, and their subsequent distillation, Agave cupreata juice as natural sugar source is the commonly used. This study aims to investigate mezcal production from Agave cupreata juice by optimizing fermentation at flask level temperature; initial content sugar; pH and initial cell concentration, using single strains, factorial fractional design was applied and for fermentation at bioreactor level 2.5 Liters a Simplex centroid design was developed to determine the most appropriate yeast consortium for producing mezcal. The fermentation process was carried out for 52 h with varied input variables, and all the models showed significant p-values for interaction of variance (< 0.05). It was produced at an optimized temperature of 32.5 °C, initial quantity sugar of 14 °Brix, pH of 5.5 and stirring agitation of 150 rpm was found that it is possible to reach ethanol concentration levels of about 5.9, 5.2, 7.3 and 4.9% v/v for S. cerevisiae, C. lusitaniae, K. marxianus and Z. bailii, respectively. Therefore K. marxianus and Z. bailii strains reached the highest production of ethanol. Fermentation broths from the mixture design were distilled and rectified determining alcohol concentration; mixtures of K. marxianus and Z. bailii reached ethanol content in their distillates, about 42.82% v/v. The developed models could predict the quality of mezcal developed from Agave cupreata using a yeast consortium.

Facultad de Ingeniería Química. Doctorado en Ciencias en Ingeniería Química In this study, the kinetic behavior of pure and mixed cultures of yeast isolated from spontaneous fermentations in a mezcal producing region in Michoacan were analyzed, using as a source of substrate Agave cupreata juice previously hydrolyzed and filtered. The Project was divided in three experimental stages: 1) The kinetic characterization of three nonconventional yeast in pure cultures: Kluyveromyces marxianus, Zygosaccharomyces bailii and Clavispora lusitania and another of the genus Saccharomyces cerevisiae. Was applied a Fractional factorial design 2^4-1 (flask level), evaluating as independent variables the temperature (25-35 °C), the initial sugars (10-14 °Brix), the pH (4.5-5.5) and the cell concentration (1-3x106 cells-ml). In this stage also was carried out the determination the output variables (% ethanol, cell growth, substrate consumption and pH), in addition to the determination of the kinetic parameters for each strain studied. 2) In the second stage, the analysis of mixed cultures between the three most ethanol productive strains (K. marxianus, S. cerevisiae and Z. bailii) was performed. For this purpose a Simplex-Reticular experimental design was applied in a stirred tank bioreactor maintaining constant the agitation (150 rpm) and the aeration (1 vvm). The conditions to carry out the different tests were: 32 °C, 14 °Brix and 5.5 of pH. 3) In the final experimental stage, the chemical analysis was performed, in which was distilled and rectified the musts fermented in the bioreactor at constant conditions (85ºC, 90 rpm). The alcoholic grade of the distillates obtained was determined and subsequently the total acidity and dry extract degree were obtained. Finally the identification and quantification of volatile compounds (ethanol, methanol, higher alcohols, aldehydes, esters, and ketones) by internal standardization by gas chromatography was conducted. el presente estudió se analizó el comportamiento cinético de cultivos puros y mixtos de levaduras asiladas de fermentaciones espontáneas de una región productora de mezcal en Michoacán, utilizando como fuente de sustrato jugo de Agave cupreata previamente hidrolizado y filtrado. Para lo cual el proyecto se estructuró en tres etapas experimentales, 1) La caracterización cinética de cultivos puros de tres levaduras no convencionales: Kluyveromyces marxianus, Zygosaccharomyces bailii y Clavispora lusitania y otra del género Saccharomyces cerevisiae. Se aplicó un diseño factorial fraccionado 2^4-1 (nivel matraz), evaluando como variables independientes la temperatura (25-35 ºC), los azúcares iniciales (10-14 ºBrix), el pH (4.5-5.5) y la concentración celular inicial (1-3-millones de células-ml). En esta etapa también se llevó a cabo la determinación de las variables de salida (% de etanol, crecimiento celular, consumo de sustrato y pH), además de la determinación de los parámetros cinéticos para cada cepa estudiada. 2) La segunda etapa consistió en el análisis de cultivos mixtos entre las 3 cepas más productivas de etanol (K. marxianus, Z. bailii y Saccharomyces cerevisiae). Para ello se formuló un diseño experimental Simplex- Reticular en un biorreactor de tanque agitado Applikon®, manteniendo constante la agitación (150 rpm) y aireación (1 vvm). Las condiciones para llevar a cabo los diferentes ensayos fueron: 32 ºC, 14 ºBrix y pH de 5.5. 3) En la última etapa experimental se realizó el análisis químico, en el cual, se destilaron y rectificaron los mostos fermentados en el biorreactor a condiciones constantes (85ºC, 90 rpm). Se determinó el grado alcohólico a los destilados obtenidos para posteriormente realizar la determinación de acidez total y extracto seco. Finalmente se realizó la identificación y cuantificación de los compuestos volátiles (etanol, metanol, alcoholes superiores, aldehídos, ésteres, y cetonas) por estandarización interna mediante cromatografía de gases.

En el presente trabajo, se efectuó una compilación de investigaciones realizadas sobre las diferentes etapas del proceso productivo del mezcal a partir de agave en algunas regiones productoras de México; con el propósito de explicar las problemáticas que enfrenta la cadena productiva agave-mezcal y las estrategias científicas que se han desarrollado para solucionarlas. Con ello se pretende lograr su resistencia y persistencia productiva en el mercado, elaborando un producto que cumpla con las características químicas establecidas por las normas oficiales mexicanas de producción y certificación de calidad, además de ofrecer posibles medidas de control en los procesos para estandarizar el producto y finalmente lograr etapas más eficientes en el proceso de producción. In this paper, a compilation of investigations of the different stages in the production process of mezcal from agave in some producers regions of Mexico is carried out; to explain some of the problems faced by the productive chain agave-mezcal and scientific strategies that are being developed in the country to solve them. This is intended to achieve its resistance and productive persistence in the market, producing a product that meets the chemical characteristics established by the Mexican official standards of production and quality certification, in addition to establishing more measures of control processes to standardize the product and finally to achieve more efficient steps in the production process.Key words: mezcal, agave, yeast, fermentation.