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Fil: Tarifa, María Clara. Universidad Nacional de Río Negro, CIT Río Negro. Río Negro, Argentina Fil: Piqueras, Cristian Martín. Planta Piloto de Ingeniería Química (UNS-CONICET). Departamento de Ingeniería Química (UNS). Buenos Aires, Argentina Fil: Genovese, Diego Bautista. Planta Piloto de Ingeniería Química (UNS-CONICET). Departamento de Ingeniería Química (UNS). Buenos Aires, Argentina. Fil: Brugnoni, Lorena Inés. Instituto de Ciencias Biológicas y Biomédicas del Sur (UNS-CONICET). Departamento de Biología, Bioquímica y Farmacia (UNS). Buenos Aires, Argentina The main objective of the research was to evaluate the performance of synbiotic delivery systems using pectin microgels on the protection of two probiotic strains (Lactobacillus casei ATCC 393 and Lactobacillus rhamnosus strain GG [ATCC 53103]) to simulated gastrointestinal digestion (GD) and storage conditions (4 ± 1 °C) in a 42 days trial. Microgel particles were prepared by ionotropic gelation method and three variables were evaluated: incubation time (24 and 48 h), free vs encapsulated cells, and presence or absence of prebiotic (commercial and Jerusalem artichoke inulin). Results demonstrated an encapsulation efficiency of 96±4% into particles with a mean diameter between 56 and 118 μm. The viability of encapsulated cells after 42 days storage stayed above 7 log units, being encapsulated cells in pectin-inulin microgels more resistant to GD compared to non-encapsulated cells or without prebiotics. In all cases incubation time influenced the strains' survival. El objetivo principal de la investigación fue evaluar el rendimiento de sistemas simbióticos utilizando microgeles de pectina para la protección de dos cepas probióticas (Lactobacillus casei ATCC 393 y Lactobacillus rhamnosus cepa GG [ATCC 53103]) frente a dos situaciones: simulación de condiciones de digestión gastrointestinal (DG) y bajo almacenamiento (4 ± 1 ° C) a lo largo de 42 días. Las partículas de microgel se prepararon mediante el método de gelificación ionotrópica y se evaluaron tres variables: tiempo de incubación (24 y 48 h), células libres vs encapsuladas y presencia o ausencia de prebióticos (inulina comercial e inulina de topinambur). Los resultados demostraron una eficiencia de encapsulación de los probióticas del 96 ± 4% en partículas con un diámetro medio entre 56 y 118 μm. La viabilidad de las células encapsuladas al termino de los 42 días de almacenamiento se mantuvo por encima de 7 unidades logarítmicas, siendo las células encapsuladas en los sistemas de microgeles pectina-inulina más resistentes a la DG en comparación con las células no encapsuladas o sin prebióticos. En todos los casos, el tiempo de incubación influyó en la supervivencia de las cepas.

The objective of this study was to evaluate in a static in vitro digestion model the survival of Lactobacillus paracasei subsp. paracasei LBC 81 in fermented chickpea and coconut beverage. The fermented beverage was stored for 1 and 8 days at 4 °C and then submitted to gastric juice, pancreatic juice, or sequential exposure to gastric and pancreatic juice. The experiment controls were (i) control 1—suspension of cells in 0.85% saline solution; (ii) control 2—cell suspension in chickpea and coconut beverage. The survival of L. paracasei was determined in log CFU/mL and expressed as a survival percentage. The survival of L. paracasei in the fermented beverage after exposure to gastric juice and sequential exposure to gastric and pancreatic juice was 99.47 + 2.05% and 93.21 + 0.43%, respectively. These values were higher than those found for controls 1 and 2. The storage condition of the fermented beverage for 1 or 8 days at 4 °C did not affect the survival after exposure to gastric juice, pancreatic juice, or sequential exposure. The results obtained in this study conclude that the fermented beverage of chickpeas and coconut is an excellent carrier for L. paracasei LBC 81, capable of enhancing survival to gastrointestinal conditions and ensuring a greater number of viable cells reaching the intestinal epithelium.

International audience; Probiotics are defined as live microorganisms that when administered in adequate amount confer a health benefit to the host. To be considered as a probiotic, a bacterial strain must not only be safe but should also survive in the human gastrointestinal tract and exert health benefits on its host. Streptococcus thermophilus is a Gram positive bacterium widely used in dairy fermentations for the production of yogurt and cheese. In contrast with other lactic acid bacteria, the probiotic status of S. thermophilus remains still questioned. This review gives an update of the human trials, in vivo assays in animal models and in vitro experiments, which have assessed the resistance of S. thermophilus to gastrointestinal stresses and have investigated its positive health effects. The underlying mechanisms of action are also described and the probiotic status of the bacterium is debated with respect to the available literature.

There is an increasing demand for non-dairy probiotic carriers such as fruit and vegetable juices. Probiotic Lactobacillus sanfranciscensis is predominantly used in the bakery industry, and its efficacy in fruit juices has not been studied sufficiently. Additionally, support from the carrier matrices for maintaining probiotic viability and gastrointestinal tolerance is important in selecting suitable vehicles for probiotic delivery. Three different non-dairy carrier juices (apple, orange and tomato) were tested for their ability to maintain L. sanfranciscensis viable during four weeks of refrigerated storage (4 &deg, C). Their potential protection of L. sanfranciscensis against in vitro gastrointestinal digestion was also evaluated. Results indicated that the probiotics viability in all three juice samples met the recommended level for probiotic food (&gt, 106&ndash, 107 cfu/mL) at the end of storage. However, all three juice samples showed a comparatively lower protective effect (p &lt, 0.05) on the viability of L. sanfranciscensis when exposed to simulated gastric juice (pH = 2) at the end of 60 min and simulated intestinal juice with 0.3% (w/v) bile salt (pH = 8) at the end of 240 min exposure. In general, the three tested juices can be regarded as the potential non-dairy based carriers for L. sanfranciscensis. The future research is needed to improve the modification of the probiotic carriers in order to prolong the viability of L. sanfranciscensis during the gastrointestinal digestion.

Probiotic microorganisms are increasingly incorporated into food matrices in order to confer proposed health benefits on the consumer. It is important that the health benefits, sensory properties, shelf-life and probiotic gastrointestinal tract (GIT) survival of these products are carefully balanced as they determine functionality and drive consumer acceptance. The strain-specific effects of probiotic species are imperative in this process but carrier matrices may play a pivotal role as well. This study therefore recapitulates the wealth of knowledge on carrier matrices and their interaction with probiotic strains. The most substantiated carrier matrices, factors that influence probiotic functionality and matrix effects on shelf-life, GIT survival and clinical efficacy are reviewed. Results indicate that carrier matrices have a significant impact on the quality of probiotic products. Matrix components, such as proteins, carbohydrates and flavoring agents, are shown to alter probiotic efficacy and viability. In vivo studies furthermore revealed strain-dependent matrix effects on the GIT survival of probiotic bacteria. However, only a limited number of studies have specifically addressed the effects of carrier matrices on the aforementioned product-parameters; most studies seem to focus solely on the strain-specific effects of probiotic microorganisms. This hampers the innovation of probiotic products. More human studies, comparing not only different probiotic strains but different carrier matrices as well, are needed to drive the innovation cycle of probiotic products.