Assessment of probiotic properties of lactic acid bacteria isolated from an artisanal Colombian cheese.

Lactic Acid Bacteria play an important role in the milk fermentation processes of traditional cheeses and have become an important target for the development of novel cheese cultures because of their ability to confer health benefits. This study aimed to evaluate the probiotic potential of 12 Lactic Acid Bacteria (LAB) strains previously isolated and molecularly identified from an artisanal Colombian Double-Cream Cheese. Probiotic properties, including safety (hemolysis and sensibility to antibiotics), pH and bile salt tolerance, auto-aggregation, cell surface hydrophobicity, antibacterial activity, and exopolysaccharide production, were examined. None of the strains were hemolytic, and Pediococcus (16, 18) and Lactobacillus (28, 29) were found to be sensitive to all antibiotics. Moreover, all the strains tolerated pH (3.0, 6.5 and 8.0) and bile salt conditions (0.3, 0.6 and 1.0 % w/v). Pediococcus pentosaceus (16), Leuconostoc citreum (17), Pediococcus acidilactici (18), Enterococcus faecium (21,22), Enterococcus faecalis (24) and Limosilactobacillus fermentum (29) exhibited medium autoaggregation and affinity to chloroform. Six of the strains exhibited a ropy exopolysaccharide phenotype. Antibacterial activity against foodborne pathogens, Salmonella Typhimurium ATCC 14028, Listeria monocytogenes ATCC 19111, Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 25923, was found to be strain dependent, with the strains 16, 18, 21, 26, 28 and 29 presenting a higher inhibition (>4 mm) against all of them. According to Principal Component Analysis, P. pentosaceus (16), Leu. mesenteroides (26), L. casei (28), L. fermentum (29), and E. faecium (21) showed strong probiotic properties. Our findings suggest that five strains out of the 12 sampled strains are potential probiotics that could be used in the processing of traditional dairy products on an industrial scale to improve their quality.

Evaluación oxidativa, microbiológica, sensorial y perfil de ácidos grasos de un yogur con ácido docosahexaenoico (DHA) extraído de aceite de microalgas / Oxidative, sensory and fatty acid profile evaluation of a yogurt with docosahexaenoic acid (DHA) extracted from microalgae oil

RESUMEN Las necesidades de ácido docosahexaenoico (DHA), se incrementan en la mujer gestante para el desarrollo visual y neurológico del feto y el lactante. En este trabajo, se desarrolló y se evaluó un yogur adicionado con aceite de microalgas, que contribuyera a la recomendación dietaria de DHA en mujeres gestantes y lactantes. Se diseñaron tres formulaciones de yogur con 0,075; 0,125 y 0,175% de aceite de microalga y se compararon con una muestra control. Se evaluaron propiedades fisicoquímicas, sensoriales, microbiológicas, perfil de ácidos grasos, potencial antioxidante (ABTS, fenoles totales) y peroxidación lipídica (sustancias reactivas al ácido tiobarbitúrico [TBARS]). Los yogures adicionados con el aceite de microalga cubrieron en 30, 45 y 63% las recomendaciones de DHA para mujeres gestantes y lactantes por porción (200 mL). Se observó estabilidad del ácido graso, excepto en la muestra de mayor adición del aceite. La muestra con adición de 0,125% de aceite de microalga fue la de mejor calificación por el panel sensorial. Todas las muestras cumplieron con el estándar microbiológico y fisicoquímico para un yogur entero adicionado con dulce. Se observó potencial antioxidante promisorio en el yogur, capaz de proteger el DHA. Se concluye que las bebidas lácteas como el yogur son matrices adecuadas para la adición de aceite de microalga con la finalidad de aumentar el DHA en la dieta, especialmente en etapas en que las necesidades de este componente son más altas, como en periodo de gestación y lactancia.

ABSTRACT The needs for docosahexaenoic acid (DHA) are increased during pregnancy for the visual and neurological development of the fetus and the breastfed infant. In this study, a yogurt with microalgae oil added to contribute to the dietary recommendation of DHA in pregnant and breastfeeding women was developed and evaluated. Three yogurt formulations were designed with 0.075; 0.125 and 0.175 microalgae oil percentage and compared with a control sample. Fatty acid profile, antioxidant potential (ABTS, total phenols), lipid peroxidation (thiobarbitrical acid reactive substances [TBARS]), physicochemical, sensory, and microbiological properties were evaluated. Yogurts with microalgae oil added covered 30, 45 and 63% of DHA recommendations for pregnant and breastfeeding women per portion (200 mL). Fat acid stability was observed, except in the one with the greatest oil addition. The sample with 0.125% of microalgae oil added was rated the highest by the sensory panel. All samples met the microbiological and physicochemical standard for a whole yogurt added with sugar. Promising antioxidant potential capable of protecting DHA was observed in the yogurt. We conclude that dairy drinks such as yogurt are suitable matrices for adding microalgae oil in order to increase DHA in the diet, especially in stages where the needs of this component are higher as is the case during pregnancy and lactation periods.

Propiedades antioxidantes de extractos de curuba (Passiflora mollisima Bailey) en crema de leche / Antioxidant properties of curuba extracts (Passiflora mollisima Bailey) in milk cream

Antecedentes: la grasa láctea contribuye al sabor y aroma de los productos lácteos y ayuda a absorber las vitaminas liposolubles. Sin embargo es susceptible a reacciones de oxidación, que traen como consecuencia una disminución en la calidad de los productos. Objetivo: evaluar la capacidad antioxidante de la crema de leche suplementada con 0,40 0,60 y 0,80% p/p de extracto de curuba y la estabilidad oxidativa durante 25 días de almacenamiento a 4ºC. Materiales y métodos: para evaluar la oxidación lipídica se determinó el valor TBAR. La capacidad antioxidante se comprobó mediante las técnicas DPPH, ORAC-H, ORAC-L y Folin Ciocalteu. Resultados: los tratamientos mejoraron significativamente la estabilidad oxidativa de la crema de leche (p<0,05) durante los 25 días de almacenamiento, la presencia de 0,40; 0,60 y 0,80% p/p de extracto de curuba redujo la producción de malondialdehido con respecto el blanco en un 6, 15 y 22% respectivamente, el poder antioxidante de las muestras suplementadas fue superior al del blanco. En la evaluación sensorial se encontró diferencia entre la crema de leche con y sin extracto. Conclusiones: el extracto de curuba retrasa el proceso de oxidación de la crema de leche y puede estar asociado a la capacidad antioxidante del producto.

Background: Milk fat contributes to flavors of dairy products and contributes to fat-soluble vitamins absorption. However, it is susceptible to oxidation reactions that result in a decrease in the quality of products. Objective: To evaluate the antioxidant capacity of the milk cream supplemented with 0.40, 0.60 and 0.80 % w/w of Banana Passion Fruit extracts and oxidative stability during 25 days of storage at 4ºC. Materials and Methods: Lipid peroxidation was evaluated by the TBARS method. The antioxidant capacity was determined by DPPH, ORAC-H, ORAC-L and Folin-Ciocalteu assays. Results: Treatments improved significantly (p<0.05) the oxidative stability of the cream during 25 days of storage, the presence of 0.40, 0.60 and 0.80% w/w curuba extract reduced production of malondialdehyde by 6, 15 and 22% respectively compared to control, the antioxidant power of the supplemented samples was higher than control. In the sensory evaluation was found difference between the cream with and without extract. Conclusions: Banana Passion Fruit extract retards the oxidation process of the cream and may be associated with the antioxidant capacity of the product.

Viabilidad de un aislado nativo de actobacillus brevis en una bebida láctea fermentada / Viability of a native isolate of Lactobacillus brevis in a fermented milky drinkl

En esta investigación se trabajó con un aislado nativo de Lactobacillus brevis obtenido de leche fermentada, al cual se le midió la viabilidad en dos bebidas lácteas fermentadas, las cuales se diferenciaban por la presencia de harina de avena al 0.5 por ciento p/v como ingrediente prebiótico, con el fin de observar su efecto en la viabilidad del probiótico. Después de elaboradas cada una de las bebidas, se les realizó un seguimiento de pH y por ciento p/v de acidez (expresada como ácido láctico), durante los días 2, 7, 14 y 21 y la prueba de viabilidad en los días 7, 14 y 21. El Lactobacillus brevis presentó viabilidad en ambas bebidas, al obtenerse recuentos mayores de 106 UFC/mL hasta el día 21, encontrándose un aumento en la velocidad de crecimiento del día 7 al 14 en la bebida con avena, aunque estadísticamente no hubo diferencia significativa.

[Viability of a native isolate of Lactobacillus brevis in a fermented milky drink]. / Viabilidad de un aislado nativo de Lactobacillus brevis en una bebida láctea fermentada.

The objective of this research was to test the viability of a native isolate of Lactobacillus brevis in two fermented milky drinks: a drink without prebiotic ingredient and another drink with oat flour (0.5%, p/v) as prebiotic ingredient. The viability of L. brevis was tested at 7, 14, and 21 after inoculation. Drink pH and lactic acid concentration was measured as a function of time (2, 7, 14, and 21 days after inoculation). The isolate was viable in both drinks because its counting plates was higher than 10(6) CFU/mL until day 21st. Between the 7th and 14th day, the rate of growth was higher in the drink that included oat flour, however, at the day 21st the colony density was similar in both drinks.