Total phenol and quercetin content and antioxidant activity in apples in response to thermal, light stress and to organic management

Flavonoids are the most abundant phenol compound group in apples, the concentration of which varies with the cultivars and climatic conditions. The objective of this study was to evaluate the effects of temperature, solar radiation, sunburn damage of the peel and the state of development of fruit on total phenol concentrations, quercetin glycosides and antioxidant activity. Three assays were conducted during the 2008/09 season to evaluate aforementioned variables on these parameters. The following season, the effect of the state of development on the fruit was evaluated. Sunburn increased phenol concentrations from 5.5 to 8.7 mg CAE* g FW-1. In relation to the state of development of the fruit, phenol concentrations decreased from 14 to 1.3 mg CAE* g FW-1 between 32 DAFB to harvest, respectively.  Fruit that was bagged until one month before harvest had significantly higher concentrations of quercetin rutinoside (28 mg*g-1FW), galactoside (484 mg*g-1FW) and glucoside (54 mg*g-1FW) than fruit that remained bagged until harvest (6, 161 and 21 mg*g-1FW, respectively). Temperature did influence phenol concentrations. This study determined that sunburn, the state of development and bagging the fruit are factors that determine phenol concentration in apples

Isolation of lactic acid bacteria from swine milk and characterization of potential probiotic strains with antagonistic effects against swine-associated gastrointestinal pathogens

Probiotics are usually isolated from the gastrointestinal tract of humans and animals. The search of probiotics in human milk is a recent field of research, as the existence of the human milk microbiome was discovered only about a decade ago. To our knowledge, no reports regarding the potential probiotic effect of bacteria from swine milk were published. In this work, we isolated several lactic acid bacteria from swine milk and evaluated them for them potential as probiotics. Among the isolated strains, Lactobacillus curvatus TUCO-5E showed antagonistic effects against swine-associated gastrointestinal pathogens. TUCO-5E was able to reduce the growth of enterotoxigenic and enterohemorragic E. coli strains as well as pathogenic Salmonella. In vitro exclusion and displacement assays in intestinal epithelial cells showed a remarkable antagonistic effect for L. curvatus TUCO-5E against Salmonella TUCO-I7 and S. enterica ATCC 13096. Moreover, by using a mice model of Salmonella infection we were able to demonstrated that L. curvatus TUCO-5E preventive administration during 5 consecutive days was capable of decreasing the number of S. typhimurium in the liver and spleen of treated mice when compared to controls, and avoided dissemination of the pathogen to the blood stream. Then, we demonstrated here that swine milk is an interesting source for finding beneficial bacteria. In addition, the results of this work suggest that L. curvatus TUCO-5E is a good candidate for in vivo studying the protective effect of probiotics against intestinal infection and damage induced by Salmonella infection in the porcine host.On isole habituellement les probiotiques du tractus gastro-intestinal d’humains et d’animaux. La recherche de probiotiques dans du lait humain est un domaine de recherche récent, puisque la découverte du microbiome laitier humain ne date que d’environ 10 ans. À notre connaissance, on n’a jamais publié de rapport sur le possible effet probiotique de bactéries issues de lait porcin. Dans le présent ouvrage, nous avons isolé plusieurs bactéries lactiques du lait porcin et avons évalué leur potentiel probiotique. Parmi les souches isolées, Lactobacillus curvatus TUCO-5E a fait preuve d’antagonisme a` l’encontre de pathogènes gastro-intestinaux porcins. TUCO-5E a su diminuer la multiplication de souches entérotoxinogènes et entérohémorragiques d’Escherichia coli et de salmonelles pathogènes. Des expériences d’exclusion et de déplacement chez des cellules épithéliales intestinales ont permis de mettre en évidence une action antagoniste remarquable exercée par L. curvatus TUCO-5E envers Salmonella sp. souche TUCO-I7 et Salmonella enterica ATCC 13096. Par ailleurs, un modèle murin d’infection a` la salmonelle nous a permis de démontrer qu’une administration préventive de L. curvatus TUCO-5E pendant 5 jours consécutifs parvenait a` réduire le nombre de Salmonella enterica serovar Typhimurium dans le foie et la rate des souris traitées, comparativement aux témoins, et a` endiguer la propagation du pathogène dans la circulation sanguine. Dès lors, nous avons démontré que le lait porcin serait une source intéressante de bactéries bénéfiques. De plus, les résultats de cette étude laissent entendre que L. curvatus TUCO-5E pourrait faire l’objet d’études in vivo sur l’effet protecteur des probiotiques envers les infections intestinales et les dommages connexes occasionnés par les salmonelles dans l’hôte porcin. [Traduit par la Rédaction].Fil: Quilodrán Vega, Sandra Rayén. Universidad de Concepción. Facultad de Ciencias Veterinarias. Laboratorio de Microbiología de los Alimentos; ChileFil: Villena, Julio Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Valdebenito, José. Universidad de Concepción. Facultad de Ciencias Veterinarias. Laboratorio de Microbiología de los Alimentos; ChileFil: Salas, María José. Universidad de Concepción. Facultad de Ciencias Biológicas. Departamento de Microbiología. Laboratorio de Patogénesis Bacteriana; ChileFil: Parra, Cristian. Universidad de Concepción. Facultad de Ciencias Biológicas. Departamento de Microbiología. Laboratorio de Patogénesis Bacteriana; ChileFil: Ruiz, Alvaro. Universidad de Concepción. Facultad de Ciencias Veterinarias. Laboratorio de Microbiología de los Alimentos; ChileFil: Kitazawa, Haruki. Tohoku University. Graduate School of Agricultural Science. Laboratory of Animal Products Chemistry. Food and Feed Immunology Group; Japón. Tohoku University. Graduate School of Agricultural Science. International Education and Research Center for Food Agricultural Immunology. Livestock Immunology Unit ; JapónFil: García, Apolinaria. Univesidad de Concepción. Facultad de Ciencias Biológicas. Laboratorio de Patogénesis Bacteriana. Grupo de Investigación de Immunobiótica; Chil