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Ceramic and polymeric membrane systems were compared at the pilot scale for separating agave fructans into different molecular weight fractions that help to diversify them into more specific industrial applications. The effect of the transmembrane pressure of ultrafiltration performance was evaluated through hydraulic permeability, permeate flux and rejection coefficients, using the same operating conditions such as temperature, feed concentration and the molecular weight cut-off (MWCO) of membranes. The fouling phenomenon and the global yield of the process were evaluated in concentration mode. A size distribution analysis of agave fructans is presented and grouped by molecular weight in different fractions. Great differences were found between both systems, since rejection coefficients of 68.6% and 100% for fructans with degrees of polymerization (DP) > 10, 36.3% and 99.3% for fructooligosaccharides (FOS) and 21.4% and 34.2% for mono-disaccharides were obtained for ceramic and polymeric membrane systems, respectively. Thus, ceramic membranes are better for use in the fractionation process since they reached a purity of 42.2% of FOS with a yield of 40.1% in the permeate and 78.23% for fructans with DP > 10 and a yield of 70% in the retentate. Polymeric membranes make for an efficient fructan purification process, eliminating only mono-disaccharides, and reaching a 97.7% purity (considering both fructan fractions) with a yield of 64.3% in the retentate.

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This work is aimed to investigate the metal content (i.e., Cu, Pb, Cd y Zn) present in Mexican spirituous beverages which include: Tequila, Raicilla, Sotol and Mezcal by using Differential Pulse Polarography (DPP). Metal content depends on the type of beverage, geographic region of origin, and aging stage. Noteworthy is metal removal, specifically copper, during the aging process of tequila, suggesting a copper capture by the oak wooden aging barrel. Metal content in aged beverages can be an alternative method to estimate both aging time and sneaky aged tequilas. Further, the results presented in this paper may provide a guide to establish metal regulations to improve quality control of spirituous Mexican beverages.

Resumen El objetivo de este estudio fue evaluar el efecto de la temperatura y tiempo de freído sobre las propiedades fisicoquímicas: porcentaje de humedad, H; cambio neto de color, ΔE; contenido de grasa, G; índices de absorción, IAA; solubilidad en agua, ISA; densidad aparente, DA; y dureza, D, de un alimento frito tipo botana preparado con una mezcla de harinas de maíz nixtamalizado (HMN), harina de chícharo (HC) y salvado de avena (SA), hidratada al 47%. El estudio mostró que DA y H disminuyeron, mientras que ΔE e IAA se incrementaron con el aumento de la temperatura y el tiempo de freído. Los cambios en ISA y D resultaron estadísticamente no significativos. El análisis de componentes principales, mostró que el 83% de la variabilidad de los datos se puede explicar debido a dos componentes: temperatura (56%) y tiempo (28%). El análisis sensorial mostró que la botana elaborada a 165 °C y 198 s obtuvo mayor aceptación, resultando un alimento con alto contenido de proteína y bajo contenido de grasa.

The objective of this work was to evaluate the effect of operating conditions and fructans size distribution on the tight Ultrafiltration process for agave fructans fractionation. A mathematical model of limiting mass flux transfer was used to represent the profile of concentrations over time at the outlet of a pilot scale ultrafiltration system. First, a Box-Behnken experimental design was performed for the optimization of the parameters that determine the operating conditions in their respective ranges: temperature, 30–60 °C; transmembrane pressure (TMP), 1–5 bar and feed concentration, 50–150 kg∙m−3, on the separation factor (SF) and permeate flux. Then, the validation of the model for different fructans size distribution was carried out. The results showed that for SF, the quadratic terms of temperature, TMP and feed concentration were the most significant factors. Statistical analysis revealed that the temperature-concentration interaction has a significant effect (p < 0.005) and that the optimal conditions were: 46.81 °C, 3.27 bar and 85.70 kg∙m−3. The optimized parameters were used to validate the hydrodynamic model; the adjustments conclude that the model, although simplified, is capable of correctly reproducing the experimental data of agave fructans fractionation by a tight ultrafiltration pilot unit. The fractionation process is favored at higher proportions of FOS:Fc in native agave fructans.

The construction and application of a monopolar, packed bed, parallel plate electrochemical flow reactor to removal of Cu+2 ions from "ordinary" (i.e., product of the first distillation of tequila) is presented. The reactor is constructed by nylomaq frameworks to accommodate copper hanks cathodes, separated from graphite anodes by means of polypropylene (Celgard®) membranes. Results of the copper concentration profile in ordinary solutions and pH variation along the reactor are reported. Copper concentration continuously decreases along the reactor reaching a removal efficiency ranging from 82 to 85% for all the inlet concentrations examined. The experimental copper concentration profile fits an exponential decay along the axial reactor coordinate, in agreement with theory for porous flow reactors. An equation deduced from the material balance for a packed bed electrode (i.e., copper hanks), that takes into account a kinetic rate constant and mass transfer coefficient to predict the concentration vs. position along the reactor is also presented.