Technological and probiotic role of adjunct cultures of non-starter lactobacilli in soft cheeses.

The influence of two cheese-isolated Lactobacillus strains on cheese composition, acceptability and probiotic capacity was assessed. Soft cheeses with and without the addition of Lactobacillus plantarum I91 or Lactobacillus paracasei I90 were prepared. Gross composition was assessed and secondary proteolysis was described by soluble fractions and free amino acids profiles. Acceptability was determined by a panel of 98 non-trained consumers. Cheeses harboring added Lactobacillus strains were also studied in vivo to evaluate their probiotic capacity. Gross composition of the cheeses was similar for control and treated (Lactobacillus-added) cheeses. Peptidolysis increased in cheeses with added lactobacilli, which was evidenced by a higher free amino acid content. Overall, the acceptability of the cheeses was good: 65%-80% of the consumers said that they "liked very much" or "liked" the cheeses. Cheeses with L. plantarum I91 showed the highest changes in composition and proteolysis and were the most accepted ones. On the contrary, composition of cheeses with L. paracasei I90 was similar to that of the controls, but these samples were less accepted than cheeses without lactobacilli. The oral administration of cheese containing L. plantarum I91 or L. paracasei I90 proved to be safe and able to enhance the number of IgA + cells in the small intestine lamina propria of mice. The use of selected strains of NSLAB exerted a technological and probiotic role: it contributed to the standardization of cheese quality and induced benefic health effects at the gut mucosa in vivo.

[Inactivated pea flour (Pisum sativum) in bread making]. / Panificación con harina de arvejas (Pisum sativum) previamente sometidas a inactivación enzimática.

Pea flour (Pisum sativum) is a relatively cheap protein source and it is scarcely utilized in making widely consumed products. It provides a good opportunity to improve the amino acidic profile. The purpose of this study was to determine the effect of the enzymatic inactivation of pea on bread characteristics, made with levels of 5, 10 and 15% of pea flour. Protein and lysine contents were determined and then chemical score obtained considering lysine as limiting amino acid. Sensory evaluation was carry out by six trained panelists using quantitative descriptive analysis (QDA) and analysis of variance (ANOVA) at p = 0.05. Residual lipoxygenase activity was 48.6% when heat treatment was made during 1 minute, and only 2.1% when the heat treatment was carry out during 1.5 minutes. Highest specific volumes of bread were obtained with pea flour treated during 1 minute. The sensory evaluation by panel determined that pea flour at a level of 5% could be successfully substituted for both heat treatments. But pea flour substitution at levels of 10 and 15% had adverse effects on specific volume and sensory characteristics.

Technological, rheological and sensory characterizations of a yogurt containing an exopolysaccharide extract from Lactobacillus fermentum Lf2, a new food additive.

Lactobacillus fermentum Lf2, an autochthonous strain isolated as a non starter culture in Cremoso cheese, produces high EPS levels (~1g/L) in optimized conditions (SDM broth, pH6.0, 30°C, 72h). Technological (texture profile and rheological analysis) and sensory properties of non-fat yogurts with 300 and 600mg EPS/L were studied at 3 and 25days after manufacture. Yogurts with different EPS concentrations showed higher hardness values than the control group at both periods of time, being the only significant difference that remained stable during time. The consistency index was also higher for the treated samples at both times evaluated, being significantly different for samples with 300mg/L of EPS extract, while the flow behavior index was lower for EPS-added yogurts. The thixotropic index was lower (P<0.05) for samples with the highest EPS extract concentration at the end of the storage time. Regarding the sensory analysis, those yogurts with 600mg/L of EPS extract presented the highest values of consistency at 3days of storage. No considerable differences for defects (milk powder, acid, bitter and cooked milk flavors) were perceived between treated and control samples at both times evaluated. Syneresis was also studied and samples with 600mg/L of EPS extract presented the lowest syneresis values at 25days of storage, which considerably decreased with the time of storage. In conclusion, the EPS from L. fermentum Lf2, used as an additive, provided yogurt with creamy consistency and increased hardness, without the presence of unwanted defects and improving the water holding capacity of the product. All the analysis done showed the potential of this extract to be used as a technofunctional natural ingredient, and it should be considered its positive impact on health, according to previous studies.

Panificación con harina de arvejas (Pisum sativum) previamente sometidas a inactivación enzimática / Inactivated pea flour (Pisum sativum) in bread making

La harina de arveja (Pisum sativum) es una fuente proteica de relativo bajo costo y escasamente utilizada en la elaboración de productos de consumo masivo. Su incorporación a la harina de trigo, en la elaboración de productos panificados, ofrece una buena alternativa para complementar un perfil de aminoácidos. En este trabajo se evalúa el efecto de la inactivación enzimática de la arveja sobre las características de los panes de molde formulados con niveles de sustitución de 5 por ciento, 10 por ciento y 15 por ciento. Se efectuaron determinaciones de proteínas y de lisina y por cálculo se obtuvieron los valores de score químico, siendo la lisina el aminoácido limitante. La evaluación sensorial se realizó con un panel de seis evaluadores entrenados y se aplicó el Análisis Descriptivo Cuantitativo. Los puntajes asignados por el panel fueron procesados estadísticamente mediante Análisis de Varianza al nivel de significación p = 0,05. La actividad residual de lipoxigenasa para el tratamiento térmico de un minuto fue de 48.6 por ciento mientras que para un minuto y medio resultó prácticamente nula (2.1 por ciento). En cuanto al efecto del tratamiento térmico de la arveja sobre el volumen específico, se aprecia que el mejor resultado se obtiene cuando el tiempo de tratamiento térmico es de un minuto. A su vez la valoración sensorial del panel asignó los mayores puntajes a los panes con nivel de sustitución de 5 por ciento de harina de arveja, para ambos tiempos de tratamiento térmico (1.0 y 1.5 min). Mayores porcentajes de harina de arveja producen un efecto negativo sobre el volumen y sobre los atributos sensoriales del pan.

Pea flour (Pisum sativum) is a relatively cheap protein source and it is scarcely utilized in making widely consumed products. It provides a good opportunity to improve the amino acidic profile. The purpose of this study was to determine the effect of the enzymatic inactivation of pea on bread characteristics, made with levels of 5, 10 and 15 percent of pea flour. Protein and lysine contents were determined and then chemical score obtained considering lysine as limiting amino acid. Sensory evaluation was carry out by six trained panelists using quantitative descriptive analysis (QDA) and analysis of variance (ANOVA) at p = 0.05. Residual lipoxygenase activity was 48.6 percent when heat treatment was made during 1 minute, and only 2.1 percent when the heat treatment was carry out during 1.5 minutes. Highest specific volumes of bread were obtained with pea flour treated during 1 minute. The sensory evaluation by panel determined that pea flour at a level of 5 percent could be successfully substituted for both heat treatments. But pea flour substitution at levels of 10 and 15 percent had adverse effects on specific volume and sensory characteristics.