RESUMEN
AIMS: Identify novel bacterial taxa that could increase the availability of branched-chain amino acids and the amount of distinctive volatiles during skim milk fermentation. METHODS AND RESULTS: We recovered 344 bacterial isolates from stool samples of healthy and breastfed infants. Five were selected based on their ability to produce branched-chain amino acids. Three strains were identified as Escherichia coli, one as Klebsiella pneumoniae and other as Klebsiella variicola by molecular and biochemical methods. HPLC and solid-phase microextraction with GC-MS were used for the determination of free amino acids and volatile compounds respectively. The consortium formed by K. variicola and four Lactobacillus species showed the highest production of Leu and Ile in skim milk fermentation. In addition, the production of volatile compounds, such as acetoin, ethanol, 2-nonanone, and acetic, hexanoic and octanoic acids, increased in comparison to commercial yogurt, Emmental and Gouda cheese. Also, distinctive volatiles, such as 2,3-butanediol, 4-methyl-2- hexanone and octanol, were identified. CONCLUSION: The use of K. variicola in combination with probiotic Lactobacillus species enhances the availability of Leu and Ile and the amount of distinctive volatiles during skim milk fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: The identified consortium increases the functional potential of fermented dairy products.
Asunto(s)
Aminoácidos de Cadena Ramificada/metabolismo , Productos Lácteos Cultivados/microbiología , Klebsiella/metabolismo , Lactobacillus/metabolismo , Compuestos Orgánicos Volátiles/metabolismo , Animales , Butileno Glicoles/metabolismo , Bovinos , Queso , Fermentación , Cetonas/metabolismo , Consorcios Microbianos , Leche/microbiología , Probióticos/metabolismo , Yogur/microbiologíaRESUMEN
Ethanolic extracts of the trunk bark of Zanthoxylum fagara, Z. elephantiasis and Z. martinicense showed activity against different species of fungi. No antibacterial activity was detected.
Asunto(s)
Antifúngicos/farmacología , Hongos Mitospóricos/efectos de los fármacos , Fitoterapia , Extractos Vegetales/farmacología , Zanthoxylum , Antifúngicos/administración & dosificación , Antifúngicos/uso terapéutico , Cuba , Relación Dosis-Respuesta a Droga , Humanos , Medicina Tradicional , Pruebas de Sensibilidad Microbiana , Corteza de la Planta , Extractos Vegetales/administración & dosificación , Extractos Vegetales/uso terapéuticoRESUMEN
The bioactive amides affinin and capsaicin isolated respectively from Heliopsis longipes roots and Capsicum spp fruits, were assayed for activity against Escherichia coli, Pseudomonas solanacearum, Bacillus subtilis and Saccharomyces cerevisicae suspension cultures. The alkamide affinin inhibited growth of E. coli and S. cerevisiae at concentrations as low as 25 microg/ml. Higher concentrations of affinin were necessary to inhibit growth of P. solanacearum and B. subtilis. However. high concentrations of capsaicin only retarded the growth of E. coli and P. solanacearum, whereas growth of B. subtilis was strongly inhibited and that of S. cerevisiae was initially enhanced. Results are discussed in relation to previous reports concerning crude extract and to the molecular structures of the bioactive compounds.