Enhanced survival of probiotics by encapsulation with plant extracts during foam-mat drying and under simulated gastrointestinal conditions

Survival of probiotic bacteria, Pediococcus pentosaceus ARG-MG12 encapsulated in sodium alginate beads with different plant extracts (onion, soybean, and lotus root) were tested under simulated gastrointestinal conditions compared with free cells. Encapsulated P. pentosaceus ARG-MG12 in sodium alginate solution with onion and soybean extracts revealed the highest survival under bile salt. The survival increased proportionately with increasing extracts concentrations. Microencapsulation enhanced acidic survival of all probiotic strains compared to free cells. P. pentosaceus ARG-MG12 coencapsulated with 3% soybean extracts showed the highest survival of 9.98 log CFU/mL (p < 0.05) after bile salt exposure for 3 hr, while the control including microencapsulated cells without extracts exhibited 8.66 log CFU/mL of survival. Alginate coating of the soybean extracts co-encapsulated probiotic increased survival during foam-mat drying at 70°C to 98.39% compared to that of uncoated which showed 87.55% survival. Co-encapsulated P. pentosaceus ARG-MG12 stored in hard gelatin capsule and aluminium foil bag at 8°C for eight weeks showed higher survival than room temperature

Dynamic changes in microbiota and mycobiota during spontaneous 'Vino Santo Trentino' fermentation

Vino Santo is a sweet wine produced from late harvesting and pressing of Nosiola grapes in a small, well-defined geographical area in the Italian Alps. We used metagenomics to characterize the dynamics of microbial communities in the products of three wineries, resulting from spontaneous fermentation with almost the same timing and procedure. Comparing fermentation dynamics and grape microbial composition, we show a rapid increase in a small number of wine yeast species, with a parallel decrease in complexity. Despite the application of similar protocols, slight changes in the procedures led to significant differences in the microbiota in the three cases of fermentation: (i) fungal content of the must varied significantly in the different wineries, (ii) Pichia membranifaciens persisted in only one of the wineries, (iii) one fermentation was characterized by the balanced presence of Saccharomyces cerevisiae and Hanseniaspora osmophila during the later phases. We suggest the existence of a highly winery-specific 'microbial-terroir' contributing significantly to the final product rather than a regional 'terroir'. Analysis of changes in abundance during fermentation showed evident correlations between different species, suggesting that fermentation is the result of a continuum of interaction between different species and physical-chemical parameter

Effect of pure and mixed cultures of the main wine yeast species on grape must fermentations

10 pages, 2 figures, 3 tables.-- Printed version published June 2010.-- The original publication is available at www.springerlink.comMixed inoculation of non-Saccharomyces yeasts and S. cerevisiae is of interest for the wine industry for technological and sensory reasons. We have analysed how mixed inocula of the main non-Saccharomyces yeasts and S. cerevisiae affect fermentation performance, nitrogen consumption and volatile compound production in a natural Macabeo grape must. Sterile must was fermented in triplicates and under the following six conditions: three pure cultures of S. cerevisiae, Hanseniaspora uvarum and Candida zemplinina and the mixtures of H. uvarum:S. cerevisiae (90:10), C. zemplinina:S. cerevisiae (90:10) and H. uvarum:C. zemplinina:S. cerevisiae (45:45:10). The presence of non-Saccharomyces yeasts slowed down the fermentations and produced higher levels of glycerol and acetic acid. Only the pure H. uvarum fermentations were unable to finish. Mixed fermentations consumed more of the available amino acids and were more complex and thus better able to synthesise volatile compounds. However, the amount of acetic acid was well above the admissible levels and compromises the immediate application of mixed cultures.The present work has been financed by the projects AGL2007-66417-C02-02/ALI and AGL2007-65498-C02-02/ALI of the Spanish Ministry of Education and Science.Peer reviewe

Stopping and restarting strategy for stochastic sequential search in global optimization

Stopping criteria, Sequential search, Pure adaptive search,