Abstract Bacanora is a Mexican distilled beverage made from agave, similar to tequila and mezcal, produced with an artisanal process. Therefore, the organoleptic characteristics of different bacanora vary highly. The aim of this study was to characterize and select native yeast involved in this artisanal process of fermentation. An initial pre-selection based upon the phenotypic characteristics of 580 strains of yeast was done, and then based on fermentation characteristics with agave juice. After pre-selection, three Saccharomyces cerevisiae and three non-Saccharomyces were chosen for the fermentative characterization. The S. cerevisiae yeasts produced 25.51 ± 1.19 g/L of ethanol at the end of the fermentation process, with a volumetric ethanol productivity of 1.76±0.17 g/L/h, while for the three non-Saccharomyces strains the parameters were 15.56± 1.68 g/L and 0.484±0.06 g/L/h, respectively. In the mixed culture of three S. cerevisiae, all remained at the end, but one of them predominates, and of the non-Saccharomyces yeasts, Torulaspora delbrueckii was the predominant yeast, according with PFGE results. The results showed that the native yeasts are adapted to the agave juice used for bacanora production, and these yeasts would contribute to improve the ethanol yields and the organoleptic characteristics of bacanora.

Resumen Bacanora es una bebida Mexicana derivada de agave, similar al tequila o mezcal producida de manera artesanal, por lo que sus características organolépticas varían altamente entre bacanoras. El objetivo de este estudio fue caracterizar y seleccionar levaduras nativas involucradas en el proceso artesanal de fermentación. Se realizó una pre-selección inicial basada en las características fenotípicas de 580 levaduras, y después una selección basada en sus características fermentativas en jugo de agave. Después de la preselección se eligieron tres S. cerevisiae y tres no-Saccharomyces. Al evaluar las características fermentativas el cultivo con Saccharomyces cerevisiae produjo al final de la fermentación, 25.51 ± 1.19 g/L de etanol, con una productividad volumétrica de etanol de 1.76±0.17 g/L/h, mientras que para el cultivo con las levaduras de no-Saccharomyces se obtuvieron 15.56± 1.68 g/L y 0.484±0.06 g/L/h respectivamente. En el cultivo mixto de S. cerevisiae, todas se mantuvieron al final, siendo una la predominante y en las levaduras no-Saccharomyces, Torulaspora delbrueckii fue la predominante esto según el seguimiento con PFGE. Las levaduras nativas están adaptadas al jugo de agave utilizado para la producción del bacanora y además pueden contribuir a mejorar el proceso fermentativo, así como, las características organolépticas sensoriales de esta exquisita bebida.

Abstract In this study, cinnamon (Cinnamomum zeylanicum), thyme (Thymus vulgaris) and Schinus molle essential oils (at 125, 250 and 500 µg/mL) were encapsulated in chitosan nanoparticles by ionotropic gelation. Their antimicrobial activity against Staphylococcus aureus ATCC 25923, Enterococcus sp., Escherichia coli ATCC 25922, Klebsiella pneumoniae (BLEE +) and Pseudomona aeruginosa carbapenemase producer was evaluated. The obtained nanoparticles exhibited a regular distribution and spherical shape with size range of 19.7 to 361 nm as observed by using a laser light scattering equipment. It was found that the studied chitosan nanoparticles with essential oils showed high antimicrobial effect than the chitosan and essential oils alone. Enterococcus sp. was the most sensitive bacteria and S. aureus the most resistant. Chitosan nanoparticles and chitosan nanoparticles with cinnamon and thyme essential oils were capable to inhibit growth of Enterococcus sp. and K. pneumoniae. This study demonstrated that chitosan nanoparticles with essential oils were effective against some foodborne pathogens.

Abstract Aspergillus and Fusarium are the fungi genera most frequently isolated from cereal grains and other commodities. They are capable of producing mycotoxins, which can affect the human and animal health. Synthetic fungicides have been used to control these fungi, nevertheless, they have acquired resistance and other alternatives are necessary since they now need higher amounts. Therefore, the aim of this study was to evaluate the efficacy of cinnamon, clove and thyme essential oils (EOs) alone and encapsulated in chitosan on the radial growth, spore germination and mycotoxin production by Fusarium verticillioides and Aspergillus parasiticus. The composition of the EOs was determined by gas chromatography mass spectrometry (GC-MS). EOs inhibited radial growth and spore germination of both fungal species better than when they were encapsulated, plus, they reduced mycotoxin production. The major components were eugenol in cinnamon and clove EO (70 and 63%, respectively) and 2-methyl-5-(1-methyethyl)-phenol (46.2%) in thyme EO. The microparticles with clove and thyme EO showed good surface charges, higher than +30 mV and their average size for the three types of microparticles was about 750 nm. Our findings suggest that EOs both alone and encapsulated in chitosan have a fungistatic effect on Fusarium verticillioides and Aspergillus parasiticus.