Biotechnological use of dairy by-products for the production and microencapsulation of the food preservative enterocin CRL35.

Bacteriocins from Gram-positive bacteria have been proposed as natural food preservative and there is a need for large-scale production for commercial purposes. The aim of the present work is to evaluate whey, a cheese industrial by-product, for the production and microencapsulation of enterocin CRL35. Whey proved to be a promising basal medium for bacterial growth although the bacteriocin production was quite low. However, it could be much favored with the addition of yeast extract at concentrations as low as 0.5%. Besides improving bacteriocin production, this peptide was successfully microencapsulated by spray drying using whey protein concentrate and a chitosan derivative as wall materials. Microcapsules averaging 10 ± 5 µm diameter were obtained, with good structural integrity and high antimicrobial activity with a stability of at least 12 weeks at 4°C. In summary, sustainable bacteriocin production and microencapsulation was achieved recycling whey or its derivatives. In addition, the formulation owns high antimicrobial activity with a long shelf life. The development of a food preservative may represent a green solution for handling whey.

Drug Repurposing: Tolfenamic Acid Inactivates PrbP, a Transcriptional Accessory Protein in Liberibacter asiaticus.

CLIBASIA_01510, PrbP, is a predicted RNA polymerase binding protein in Liberibacter asiaticus. PrbP was found to regulate expression of a small subset of ribosomal genes through interactions with the ß-subunit of the RNA polymerase and a short, specific sequence on the promoter region. Molecular screening assays were performed to identify small molecules that interact with PrbP in vitro. Chemical hits were analyzed for therapeutic efficacy against L. asiaticus via an infected leaf assay, where the transcriptional activity of L. asiaticus was found to decrease significantly after exposure to tolfenamic acid. Similarly, tolfenamic acid was found to inhibit L. asiaticus infection in highly symptomatic citrus seedlings. Our results indicate that PrbP is an important transcriptional regulator for survival of L. asiaticus in planta, and the chemicals identified by molecular screening assays could be used as a therapeutic treatment for huanglongbing disease.

Biopolymers from lactic acid bacteria. Novel applications in foods and beverages.

Lactic acid bacteria (LAB) are microorganisms widely used in the fermented food industry worldwide. Certain LAB are able to produce exopolysaccharides (EPS) either attached to the cell wall (capsular EPS) or released to the extracellular environment (EPS). According to their composition, LAB may synthesize heteropolysaccharides or homopolysaccharides. A wide diversity of EPS are produced by LAB concerning their monomer composition, molecular mass, and structure. Although EPS-producing LAB strains have been traditionally applied in the manufacture of dairy products such as fermented milks and yogurts, their use in the elaboration of low-fat cheeses, diverse type of sourdough breads, and certain beverages are some of the novel applications of these polymers. This work aims to collect the most relevant issues of the former reviews concerning the monomer composition, structure, and yields and biosynthetic enzymes of EPS from LAB; to describe the recently characterized EPS and to present the application of both EPS-producing strains and their polymers in the fermented (specifically beverages and cereal-based) food industry.

Antifungal starter culture for packed bread: influence of two storage conditions / Fermento láctico antifúngico para panificados envasados: influencia de dos condiciones de almacenamiento

In this study, we analyzed the conservation of a semi-liquid bio-preserver (SL778) developed with Lactobacillus plantarum CRL 778, a lactic acid bacterium (LAB) having antifungal activity. The characteristics of the SL778 starter remained stable during a 14-day storage at 4 °C. At −20 °C, cell viability and organic acid concentration showed a significant (p < 0.05) decrease after 7 days. These differences observed between the storage temperatures tested were reflected in the acidification activity of SL778 during dough fermentation. However, SL778 maintained its antifungal efficacy up to a 14-day storage at both temperatures. Sensory attributes (acidic and spicy tastes and acidic smell) of breads manufactured with starter SL778 (stored at 4 or −20 °C) were evaluated. No undesirable difference was detected with respect to bread control without SL778 and bread manufactured with SL778 (stored at 4 or −20 °C). In conclusion, the SL778 semi-liquid bio-preserver can be stored at 4 or −20 °C without modifying its antifungal activity during 14 days.

Se evaluó la estabilidad de un bioconservante semilíquido destinado a panificados envasados, desarrollado con la bacteria láctica con actividad antifúngica Lactobacillus plantarum CRL 778. Las características del bioconservante, designado como SL778, se mantuvieron estables durante 14 días de almacenamiento a 4 °C. A -20 °C, la viabilidad celular y la concentración de ácidos orgánicos disminuyeron significativamente (p < 0,05) después de 7 días de almacenamiento. Estas diferencias según la temperatura de almacenamiento se reflejaron en la actividad acidificante de SL778 durante la fermentación de las masas. Sin embargo, SL778 mantuvo su eficacia antifúngica por hasta 14 días con el almacenamiento a ambas temperaturas. Se evaluaron los atributos sensoriales de los panificados elaborados con SL778 (gusto ácido y picante y olor ácido) tras el almacenamiento a las dos temperaturas. En tal sentido, los panelistas no detectaron diferencias que vuelvan al producto indeseable al comparar los panificados control (sin SL778) y los elaborados con SL778, tanto almacenados a 4 °C como a -20 °C. En conclusión, el bioconservante semilíquido SL778 se puede almacenar a 4 °C o a -20 °C durante 14 días sin que ocurran cambios en su actividad antifúngica.

Antifungal starter culture for packed bread: influence of two storage conditions / Fermento láctico antifúngico para panificados envasados: influencia de dos condiciones de almacenamiento

In this study, we analyzed the conservation of a semi-liquid bio-preserver (SL778) developed with Lactobacillus plantarum CRL 778, a lactic acid bacterium (LAB) having antifungal activity. The characteristics of the SL778 starter remained stable during a 14-day storage at 4 °C. At −20 °C, cell viability and organic acid concentration showed a significant (p < 0.05) decrease after 7 days. These differences observed between the storage temperatures tested were reflected in the acidification activity of SL778 during dough fermentation. However, SL778 maintained its antifungal efficacy up to a 14-day storage at both temperatures. Sensory attributes (acidic and spicy tastes and acidic smell) of breads manufactured with starter SL778 (stored at 4 or −20 °C) were evaluated. No undesirable difference was detected with respect to bread control without SL778 and bread manufactured with SL778 (stored at 4 or −20 °C). In conclusion, the SL778 semi-liquid bio-preserver can be stored at 4 or −20 °C without modifying its antifungal activity during 14 days.(AU)

Se evaluó la estabilidad de un bioconservante semilíquido destinado a panificados envasados, desarrollado con la bacteria láctica con actividad antifúngica Lactobacillus plantarum CRL 778. Las características del bioconservante, designado como SL778, se mantuvieron estables durante 14 días de almacenamiento a 4 °C. A -20 °C, la viabilidad celular y la concentración de ácidos orgánicos disminuyeron significativamente (p < 0,05) después de 7 días de almacenamiento. Estas diferencias según la temperatura de almacenamiento se reflejaron en la actividad acidificante de SL778 durante la fermentación de las masas. Sin embargo, SL778 mantuvo su eficacia antifúngica por hasta 14 días con el almacenamiento a ambas temperaturas. Se evaluaron los atributos sensoriales de los panificados elaborados con SL778 (gusto ácido y picante y olor ácido) tras el almacenamiento a las dos temperaturas. En tal sentido, los panelistas no detectaron diferencias que vuelvan al producto indeseable al comparar los panificados control (sin SL778) y los elaborados con SL778, tanto almacenados a 4 °C como a -20 °C. En conclusión, el bioconservante semilíquido SL778 se puede almacenar a 4 °C o a -20 °C durante 14 días sin que ocurran cambios en su actividad antifúngica.(AU)

Antifungal starter culture for packed bread: influence of two storage conditions.

In this study, we analyzed the conservation of a semi-liquid bio-preserver (SL778) developed with Lactobacillus plantarum CRL 778, a lactic acid bacterium (LAB) having antifungal activity. The characteristics of the SL778 starter remained stable during a 14-day storage at 4°C. At -20°C, cell viability and organic acid concentration showed a significant (p<0.05) decrease after 7 days. These differences observed between the storage temperatures tested were reflected in the acidification activity of SL778 during dough fermentation. However, SL778 maintained its antifungal efficacy up to a 14-day storage at both temperatures. Sensory attributes (acidic and spicy tastes and acidic smell) of breads manufactured with starter SL778 (stored at 4 or -20°C) were evaluated. No undesirable difference was detected with respect to bread control without SL778 and bread manufactured with SL778 (stored at 4 or -20°C). In conclusion, the SL778 semi-liquid bio-preserver can be stored at 4 or -20°C without modifying its antifungal activity during 14 days.