Pozol is an acid beverage obtained from the natural fermentation of nixtamal (heat-and alkali-treated maize) dough. The concentration of mono-and disaccharides from maize is reduced during nixtamalization, so that starch is the main carbohydrate available for lactic acid fermentation. In order to provide some basis to understand the role of amylolytic lactic acid bacteria (ALAB) in this fermented food, their diversity and physiological characteristics were determined. Forty amylolytic strains were characterized by phenotypic and molecular taxonomic methods. Four different biotypes were distinguished via ribotyping; Streptococcus bovis strains were found to be predominant. Streptococcus macedonicus, Lactococcus lactis, and Enterococcus sulfureus strains were also identified. S. bovis strain 25124 showed extremely low amylase yield relative to biomass (139 U g [cell dry weight] ؊1 ) and specific rate of amylase production (130.7 U g [cell dry weight] ؊1 h ؊1 ). In contrast, it showed a high specific growth rate (0.94 h ؊1 ) and an efficient energy conversion yield to bacterial cell biomass (0.31 g of biomass g of substrate ؊1 ). These would confer on the strain a competitive advantage and are the possible reasons for its dominance. Transient accumulation of maltooligosaccharides during fermentation could presumably serve as energy sources for nonamylolytic species in pozol fermentation. This would explain the observed diversity and the dominance of nonamylolytic lactic acid bacteria at the end of fermentation. These results are the first step to understanding the importance of ALAB during pozol fermentation.Amylolytic lactic acid bacteria (ALAB) have been reported from different tropical amylaceous fermented foods, prepared mainly from cassava and cereals (e.g., maize and sorghum). Amylolytic strains of Lactobacillus plantarum have been isolated from African cassava-based fermented products (26), and the new ALAB species Lactobacillus manihotivorans (23) was isolated from cassava sour starch fermentations carried out in Colombia. ALAB have also been isolated from cereal-based fermented foods. Olympia et al. (27)

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Glucovanillin was extracted from green pods and simultaneously transformed to vanillin by a combination of enzyme activities involving cell wall degradation and glucovanillin hydrolysis. The reaction is best carried out with 47.5% v/v aqueous ethanol solution during 8 h at 70 degrees C, in a two-step enzymatic reaction using Viscozyme followed by Celluclast, two commercial enzymatic products containing mainly pectinase and cellulase activities, respectively. The extractive reaction proceeded with high efficiency with an amount of extracted vanillin 3.13 times higher than the one obtained with the Soxhlet method. The classical curing/extraction process results in 1.1-1.8 g of vanillin/100 g of dry pods. It is concluded that the enzymatic reaction may substitute the microbial process involved in tissue fermentation previous to vanillin extraction with the simultaneous hydrolysis of glucovanillin.

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Artisanal mezcal is produced by the natural fermentation of maguey juice, which frequently results in a process that becomes stuck or is sluggish. Using selected indigenous starter inoculums of Saccharomyces and non-Saccharomyces yeasts is considered beneficial in overcoming these problems and thereby preserving the essence of the artisanal process. In this work, three hundred and four yeast isolates were recovered from 17 distilleries and then grouped by the ARDRA analysis, their restriction profiles were clustered in 15 groups. Four of them included 90% of all isolates, and these were identified using the sequence of the D1/D2 domain of the large-subunit rDNA. Pichia kudriavzevii, Pichia manshurica, Saccharomyces cerevisiae, and Kluyveromyces marxianus were detected as predominant species. Both species belonging to the Pichia genus were detected in 88% of the distilleries, followed by S. cerevisiae (70%) and K. marxianus (50%). In order to evaluate the fermentative capacity, one strain of each species was assessed in a pure and mixed culture in two culture media, filtered maguey juice (MJ) and maguey juice including its bagasse (MJB). Findings demonstrated that non-Saccharomyces yeast presented better growth than that of S. cerevisiae. K. marxianus PA16 was more efficient for ethanol production than S. cerevisiae DI14. It produced 32 g/L of ethanol with a yield of 0.47 g/g and efficient of 90%. While, P. kudriavzevii produced more ethyl acetate (280 mg/L) than the others species. All fermentations were characterized by the presence of isobutyl and isoamyl alcohol. The presence of K. marxianus in a mixed culture, improved the ethanol production and volatile compounds increased using co-cultures.