Determination of antioxidant activity and phenolic compounds in different Mexican craft beers

The objective of the present study was to evaluate and compare the phenolic content (total phenols and flavonoids) and the antioxidant capacity of seventeen craft beers produced in Mexico. The results showed a considerable amount of content of total phenols and flavonoids in the styles Coffee Stout Imperial (362 mg GAE/L and 75 mg QE/L) and Stout Ale (299 mg GAE/L and 40.92 mg QE/L), followed by American Brown Ale (271 mg GAE/L and 27.35 mg QE/L), Brown Ale (211 mg GAE/L and 24.20 mg QE/L), and Dark (328 mg GAE/L and 20.94 mg QE/L). In contrast, the American Wheat Ale (65 mg GAE/L and 2.91 mg QE/L), Lager (102 mg GAE/L and 3.56 mg QE/L), and IPA (103.73 mg GAE/L and 3.75 mg QE/L) showed the lowest content of phenols and flavonoids. The antioxidant capacity is detected in all the beers evaluated, mainly in the Coffee Stout Imperial style beer (80%). In this study, different contents of total carbohydrates were observed according to the type of beer, with Coffee Stout Imperial, American Brown Ale, and Brown being the ones that presented the highest content of carbohydrates (24.25, 15.55, and 15.36 g/L, respectively) followed by the type of Pilsner beer. (13.60g/L). Finally, our study showed that the different styles of beers in Mexico presented different contents of polyphenols (phenols and flavonoids), antioxidant capacity, and carbohydrates. However, the Coffee Stout Imperial style beer showed the highest values ​​of the aforementioned parameters. Future studies should be carried out in the evaluation of the biological activity of the different styles of beers on nutritional parameters in the Mexican population.El objetivo del presente estudio fue evaluar y comparar el contenido fenólico (fenoles y flavonoides totales) y la capacidad antioxidante de diecisiete cervezas artesanales producidas en México. Los resultados mostraron una cantidad considerable de contenido de fenoles totales y flavonoides en los estilos Coffee Stout Imperial (362 mg GAE/L y 75 mg QE/L) y Stout Ale (299 mg GAE/L y 40,92 mg QE/L), seguidos por American Brown Ale (271 mg GAE/L y 27,35 mg QE/L), Brown Ale (211 mg GAE/L y 24,20 mg QE/L) y Dark (328 mg GAE/L y 20,94 mg QE/L). En contraste, la American Wheat Ale (65 mg GAE/L y 2,91 mg QE/L), Lager (102 mg GAE/L y 3,56 mg QE/L) e IPA (103,73 mg GAE/L y 3,75 mg QE/L) mostraron el menor contenido. La capacidad antioxidante se detectó en todas las cervezas evaluadas, principalmente en la de estilo Coffee Stout Imperial (80 %). En este estudio se observaron diferentes contenidos de carbohidratos totales según el tipo de cerveza, donde las Coffee Stout Imperial, American Brown Ale y Brown fueron las que presentaron el mayor contenido de carbohidratos (24,25, 15,55 y 15,36 g/L, respectivamente), seguidas del tipo Pilsner. (13,60g/L). Finalmente, nuestro estudio mostró que los diferentes estilos de cervezas en México presentaron diferentes contenidos de polifenoles (fenoles y flavonoides), capacidad antioxidante y carbohidratos. No obstante, las cervezas estilo Coffee Stout Imperial mostraron tener los mayores valores de los parámetros antes mencionados. Futuros estudios deben ser realizados en la evaluación de la actividad biológica de los diferentes estilos de cervezas sobre parámetros de nutrición en la población mexicana

Inoculantes comerciales en Baja California, México: calidad y capacidad de biocontrol de hongos fitopatógenos

In the present study, the biological quality and cell viability of different microbial inoculants marketed in Baja California, Mexico, was carried out. For this purpose, the antagonistic capacity was determined in triplicate by means of dual confrontation with phytopathogenic fungi, determination of cell viability using the serial dilution technique in culture medium; as well as the review of compliance with the packaging criteria based on the Mexican regulations in the products: Bioben, T-22, Funqui, Agroderma, Bio-Tilis, Enerbac, Fus-Out and Bacillus 1537. The results showed that the products Agroderma, Bacillus 1537 and Fus-Out, no health registration submitted. On the other hand, the viability of the inoculants evaluated by means of the plate count technique, showed values ​​of CFU/g or CFU/mL, lower than those indicated by the labels of the commercial inoculants. The results of antagonism of biological fungi against phytopathogenic fungi: Alternaria alternata, Macrophomina sp., Fusarium solani, and Botrytis sp., showed that only the product formulated based on Bacillus 1537 presented an inhibitory effect greater than 50% on phytopathogens. evaluated. In contrast, the products formulated based on mycoparasitic fungi, showed a lower efficiency of inhibition of phytopathogenic fungi, being the Funqui inoculant, the one that presented the capacity to inhibit their growth by 50%. Finally, Baja California has a wide presence of commercial inoculants; however, its quality and biological efficiency is variable against the pathogens present in the agricultural soils of the region.En el presente estudio se realiza una evaluación de la calidad biológica y viabilidad celular de diferentes inoculantes microbianos comercializados en Baja California, México. Para tal fin, se determina por triplicado la capacidad antagónica mediante la confrontación dual con hongos fitopatógenos, la viabilidad celular usando la técnica de dilución en serie en medio de cultivo; así como la revisión del cumplimiento de los criterios de criterios de rotulación de etiqueta con base a la normativa mexicana en los productos: Bioben, T-22, Funqui, Agroderma, Bio-Tilis, Enerbac, Fus-Out y Bacillus 1537. Los resultados mostraron que los productos Agroderma, Bacillus 1537 y Fus-Out, no presentaron registro sanitario. Por otra parte, la viabilidad de los inoculantes evaluados mediante la técnica de conteo en placa, mostraron valores de UFC/g o UFC/mL, inferiores a los indicados por las etiquetas de los inoculantes comerciales. Los resultados de antagonismos de los productos biológicos contra los hongos fitopatógenos: Alternaria alternata, Macrophomina sp., Fusarium solani, y Botrytis sp., mostraron que solo el producto formulado a base de Bacillus 1537 presentó un efecto inhibitorio mayor del 50% sobre los hongos fitopatógenos evaluados. En contraste, los productos formulados a base de hongos mico-parásitos, mostraron una menor eficiencia de inhibición de hongos fitopatógenos, siendo el inoculante Funqui, el que presentó la capacidad de inhibir el crecimiento de estos en un 50%. Finalmente, Baja California cuenta con una amplia presencia de inoculantes comerciales; no obstante, su calidad y eficiencia biológica es variable contra los agentes patógenos presentes en los suelos agrícolas de la región

Advances and Trends in the Physicochemical Properties of Corn Starch Blends

Corn starch is one of the most widely used biopolymers in the world for various applications, due to its high production, renewable, low cost, non-toxic, biodegradable and provide great stereochemical diversity by presenting a complex structure with unique qualities that they depend on multiple factors to obtain special properties for a specific use and/or of interest. From the synthesis of the starch granule to its extraction for its subsequent use, it promotes innovative characteristics, presenting infinite functionalities applicable and/or as a substitute for synthetic polymers. However, some limitations of hydrophilicity, thermal and mechanical properties, rapid degradability and strong intra and intermolecular bonds of the polymer chains make their use difficult in the medium and long term. Enzymatic, chemical and physical methods continue to be used today, creating by-products such as polluting waste and which can be costly. Therefore, the polymeric modification of the starch granule is necessary to mitigate limitations and by-products, currently the use of starch blends is a promising trend to produce new and innovative desirable properties. This chapter describes the advances and trends in the physicochemical properties of corn starch blends Zea mays L. as a potential material, leader for its attractive properties and benefits that it has to offer, demonstrating that when combined with other starches from different botanical sources and/or molecular structure present unique and unequaled synergisms

“ESTUDIO DE LOS MECANISMOS DE REMOCION DE HEXADECANO POR LOS CULTIVOS PUROS Y MIXTOS DERIVADOS DE UN CONSORCIO BACTERIANO”

El objetivo de este trabajo fue determinar los mecanismos de remoción de hexadecano (HXD) empleados por los cultivos puros y mixtos, derivados de un consorcio bacteriano, durante la degradación de HXD. Las cepas bacterianas se aislaron de muestras de un biorreactor de columna de burbujas, operado en ciclos secuenciales de 14 días, con HXD como única fuente de carbono y energía. El biorreactor fue inicialmente inoculado con una suspensión bacteriana aislada de la rizósfera de Cyperus laxus Lam, una planta nativa que crece cerca de una refinería de petróleo en operación en el Estado de Veracruz. Se aislaron cuatro cepas bacterianas y fueron identificadas mediante la secuenciación del gen ribosomal RNAr 16S como: Xanthomonas sp. UAM58, Acinetobacter bouvetii UAM25, Shewanella sp. UAM38 y Defluvibacter lusatiensis UAM86. Los estudios de degradación de HXD se desarrollaron en botellas serológicas (125 mL) con 50 mL de medio mineral salino (MMS), 13 g/L de HXD, y un inóculo de 1x106 UFC/mL. Los cultivos se desarrollaron por triplicado (30°C; 200 rpm; 15 días) realizando un muestreo a los 0, 2, 5, 10 y 15 días de cultivo. Las variables de respuesta analizadas fueron: la concentración de HXD, el crecimiento bacteriano, la hidrofobicidad celular, la capacidad de pseudosolubilización y emulsificación del HXD. Con el propósito de conocer los sistemas enzimáticos involucrados en la oxidación del HXD se investigaron diferentes genes catabólicos mediante PCR. En esta etapa se logró identificar los genes alkB y alkM. Los biosurfactantes se detectaron mediante las siguientes pruebas: tensión superficial, colapso de la gota y desplazamiento de la gota del petróleo. Esta última prueba también fue empleada para determinar, indirectamente, la concentración de biosurfactactantes expresada como equivalentes de Tween 20. Al cabo de 15 días de cultivo se encontró que la capacidad para degradar HXD fue diferente para cada cepa por separado. Se observó que la eficiencia de degradación de HXD fue significativamente mayor para A. bouvetii (72±4%), seguida de Xanthomonas sp. (46±4%) y D. lusatiensis (40±6%). Shewanella sp. no fue capaz de utilizar HXD como única fuente de carbono y energía. Se identificaron los genes que codifican para la alcano monooxigenasa en los cultivos puros y se identificó el gen homólogo alkM en A. bouvetii. Además, A. bouvetii fue la única cepa del consorcio productora de biosurfactantes alcanzando una máxima concentración a los 5 días (0.17 ± 0.03 g/L de equivalentes de Tween 20). Con base en la capacidad de degradación de HXD de los cultivos puros, se diseñaron y evaluaron cuatro cultivos mixtos. Se observó un incremento en la degradación de HXD, particularmente, en los cultivos Xanthomonas sp.+A. bouvetii (74±7%) y el consorcio bacteriano, constituido por las cuatro cepas (79±3%). Los mecanismos de remoción de HXD se evaluaron en el cultivo puro de A. bouvetii, el cultivo mixto integrado por Xanthomonas sp.+A. bouvetii y el consorcio, debido a su alta eficiencia de degradación de HXD. Se consideraron las cinéticas de hidrofobicidad celular, la capacidad de pseudosolubilización y emulsificación de HXD para determinar los mecanismos de remoción. Los resultados indicaron que A. bouvetii empleó tanto el contacto directo como la remoción mediada por biosurfactantes para la degradación de HXD. En el caso de los cultivos Xanthomonas sp.+A. bouvetii y el consorcio bacteriano, ambos mecanismos tomaron lugar; pero la remoción facilitada por biosurfactantes fue predominante al finalizar el tiempo de cultivo. En particular, en el consorcio la emulsificación fue predominante después de los 5 días de cultivo. Por lo tanto, los cambios en la hidrofobicidad celular y el grado de pseudosolubilización o emulsificación, fueron factores clave para la remoción de sustratos hidrofóbicos por los cultivos puros y mixtos evaluados. Además las asociaciones poblacionales entre las cepas del consorcio bacteriano, jugaron un papel importante en los mecanismos de remoción de HXD. Este trabajo es el primer estudio que muestra la capacidad degradadora de hidrocarburos de D. lusatiensis y A. bouvetii. Asimismo, este estudio revela a A. bouvetii como una cepa productora de biosurfactantes. Finalmente, este trabajo contribuye a entender los mecanismos de remoción de hidrocarburos entre cultivos bacterianos puros y mixtos.The aim of this study was to determine the mechanisms of hexadecane (HXD) uptake among pure and mixed cultures, derived from a bacterial consortium, during of HXD transformation. Bacterial strains were isolated from samples a bubble column reactor operated in sequential batch, with HXD as sole carbon source and energy. The bioreactor was initially inoculated with a bacterial suspension obtained from rhizosphere of Cyperus Laxus Lam, a native plant able to grow in a highly contaminated swamp adjacent to an operating refinery in Veracruz. Four bacterial strains were isolated and identified by nucleotide sequence analysis (16S rRNA gene). The bacterial strains were identified as Xanthomonas sp., Acinetobacter bouvetii, Shewanella sp. and Defluvibacter lusatiensis. Biodegradation assays were conducted in 125 mL serological bottles containing a saline mineral medium (SMM), HXD (13 g/L) and an inoculum of 1x106 CFU /mL. Cultures were performed in triplicate (30°C; 200 rpm; 15 days) and sampled at 0, 2, 5, 10 and 15 days. Analyses of residual HXD, bacterial growth, cell surface hydrophobicity, pseudosolubilization and emulsification capacity were determined. In order to determine enzymatic systems involved in the HXD degradation, we identified different catabolic genes by PCR. As a result, we identified the alkB and alkM genes. Biosurfactants were detected by the following methods: surface tension, collapsed drop and oil spreading. Biosurfactant concentration was indirect determined by the oil spred method and expressed as equivalents of Tween 20. After 15 days growth, HXD was degraded by the pure cultures of A. bouvetii (72±4%), Xanthomonas sp. (46±4%) and D. lusatiensis (40±6%), but not by Shewanella sp. We identified the alkM gene in A. bouvetii. In addition, A. bouvetii was the only biosurfactant producer, reaching a maximum concentration at 5 days (0.17 ± 0.03 g/L equivalents of Tween 20). Based on degrading abilities of pure cultures, we tested four mixed cultures. As a result, the mixed cultures showed and enhanced HXD degradation, particularly with the culture Xanthomonas sp.+A. bouvetii (74±7%) and the bacterial consortium (79±3%). Since A. bouvetii, the culture with Xanthomonas sp.+A. bouvetii and the consortium were the best degraders, the mechanisms of HXD uptake were determined. The kinetics of cell surface hydrophobicity, the pseudosolubilization and emulsification capacities were considered to characterize the uptake mechanisms. Our findings showed that A. bouvetii combined both direct contact and biosurfactant-mediated uptake. For the culture Xanthomonas sp.+A. bouvetii and the consortium both mechanisms took place; however, the biosurfactant-mediated uptake was predominant at the end of culture time. Particularly, the emulsification was predominant in the consortium after 5 days. The changes in the cell surface hydrophobicity and the pseudosolubilization and emulsification extent were key factors for the hydrophobic substrate degradation. Also, associations among members of the consortium, played an important role in the uptake mechanisms by the mixed cultures. This is the first report of D. lusatiensis and A. bouvetii as hydrocarbon degrader strains and reveals A. bouvetii as a biosurfactant producer. Our results contribute to understand the HXD uptake mechanisms by pure and mixed cultures

Silver nanoparticles from Prosopis glandulosa and their potential application as biocontrol of Acinetobacter calcoaceticus and Bacillus cereus

In the present study the characterization and properties of silver nanoparticles from Prosopis glandulosa leaf extract (AgNPs) were investigated using UV–Vis spectroscopic techniques, energy dispersive X-ray spectrometers (EDS), zeta potential and dynamic light scattering. The UV–Vis spectroscopic analysis showed the absorbance peaked at 487 nm, which indicated the synthesis of silver nanoparticles. The experimental results showed silver nanoparticles had Z-average diameter of 421 nm with higher stability (−200 mV). The EDS analysis also exhibited presentation of silver element. Additionally, the different concentrations of AgNPs (25, 50, 75 and 100 mg/mL) showed antibacterial activity against Acinetobacter calcoaceticus and Bacillus cereus. Finally, AgNPs from leaf extracts of P. glandulosa may be used as an agent of biocontrol of microorganism of importance medical. However, further studies will be needed to fully understand the antimicrobial activity of silver nanoparticles obtain from P. glandulosa

Keratinases from Streptomyces netropsis and Bacillus subtilis and Their Potential Use in the Chicken Feather Degrading

Feathers are the most prevalent agricultural waste generated by chicken farms, polluting the environment and wasting protein resources as a result of the accumulation of large amounts of feathers. Therefore, keratinase-producing microorganisms represent a promising potential technique for the degradation of feather waste. Streptomyces netropsis A-ICA and Bacillus subtilis ALICA, previously isolated from the rhizosphere of desert plants (Larrea tridentata and Prosopis juliflora) respectively, were assessed for their feather-degradation ability. Keratinase activity was optimized using various parameters, including incubation time, pH, temperature, and feather concentration. The maximum keratinase activity of S. netropsis A-ICA and B. subtilis ALICA (113.6 ± 5.1 and 135.6 ± 4.1 U/mL) was obtained at the 5th and 3rd day of incubation with initial pH of 7.0 and 7.5 at 25 and 30 °C, and 1% (w/v) of chicken feather, respectively. Under the optimized conditions, the concentration of soluble protein in the feather hydrolysate reached 423.3 ± 25 and 565.3 ± 7.7 µg/mL, with feathers weight loss of 84 ± 2 and 86± 1.5% by S. netropsis A-ICA and B. subtilis ALICA, respectively. The highest disulphide bond reductase activity reached 10.7 ± 0.4 and 1.96 ± 1.1 U/mL, after five and three days of inoculation with S. netropsis A-ICA and B. subtilis ALICA, respectively. Furthermore, the antioxidant activity of feather protein hydrolysate obtained by S. netropsis A-ICA and B. subtilis ALICA was evaluated using DPPH radical-scavenging activity, which exhibited a significant antioxidant potential with an IC50 value of 0.8 and 0.6 mg/mL. The 3D models of detected keratinases in both strains showed high similarity with subtilisin family. Further, the docking results clarified the importance of GSG and VVVFTP domains in B. subtilis and beta-keratin, respectively. The present study revealed the keratinolytic potential of S. netropsis A-ICA and B. subtilis ALICA in chicken feather degradation, which have potential application value and may be exploited as supplementary protein and antioxidant in animal feed formulations

Changes of photochemical efficiency and epidermal polyphenols content of Prosopis glandulosa and Prosopis juliflora leaves exposed to cadmium and copper

The effect of metals on the photosynthetic activities and epidermal polyphenol content of Prosopis glandulosa and Prosopis juliflora leaves was investigated by the tissue tolerance test. Foliar tissues of Prosopis glandulosa and Prosopis juliflora were incubated with Cd2+ (0.001 M) or Cu2+ (0.52 M) concentrations for 96 h. The results showed that significant reductions (p < 0.05) of photochemical efficiency in P. juliflora leaves were found after 96 h of exposure to 0.52 M Cu2+ compared with Cd-treatments and controls. In contrast, P. glandulosa leaves showed a progressive increase on photochemical efficiency at 72 h after Cu-treatment. The results also showed a significant decrease (p < 0.05) of epidermal polyphenols in P. juliflora leaves after 24 h of exposure to 0.52 M Cu2+ compared with Cd-treatments and control leaves. On the other hand, the values of leaf epidermal polyphenols observed in P. glandulosa exposed to copper and cadmium did not show any difference with respect to control. These findings are very important and suggest that these compounds could be considered as a protection mechanism of P. glandulosa when is treated with these heavy metals. Finally, the results of bioaccumulation showed that the copper concentration in P. glandulosa was higher than the values detected in P. juliflora Nevertheless, the cadmium concentration in foliar tissues of P. juliflora was significantly higher than P. glandulosa after 96 h of exposure to Cu2+ or Cd2+. Therefore, future studies are necessary to elucidate the effects of heavy metals on the biosynthesis of flavonoids and participation of these compounds in the reduction of metal toxicity in Prosopis species

Keratinases from <i>Streptomyces netropsis</i> and <i>Bacillus subtilis</i> and Their Potential Use in the Chicken Feather Degrading

Feathers are the most prevalent agricultural waste generated by chicken farms, polluting the environment and wasting protein resources as a result of the accumulation of large amounts of feathers. Therefore, keratinase-producing microorganisms represent a promising potential technique for the degradation of feather waste. Streptomyces netropsis A-ICA and Bacillus subtilis ALICA, previously isolated from the rhizosphere of desert plants (Larrea tridentata and Prosopis juliflora) respectively, were assessed for their feather-degradation ability. Keratinase activity was optimized using various parameters, including incubation time, pH, temperature, and feather concentration. The maximum keratinase activity of S. netropsis A-ICA and B. subtilis ALICA (113.6 ± 5.1 and 135.6 ± 4.1 U/mL) was obtained at the 5th and 3rd day of incubation with initial pH of 7.0 and 7.5 at 25 and 30 °C, and 1% (w/v) of chicken feather, respectively. Under the optimized conditions, the concentration of soluble protein in the feather hydrolysate reached 423.3 ± 25 and 565.3 ± 7.7 µg/mL, with feathers weight loss of 84 ± 2 and 86± 1.5% by S. netropsis A-ICA and B. subtilis ALICA, respectively. The highest disulphide bond reductase activity reached 10.7 ± 0.4 and 1.96 ± 1.1 U/mL, after five and three days of inoculation with S. netropsis A-ICA and B. subtilis ALICA, respectively. Furthermore, the antioxidant activity of feather protein hydrolysate obtained by S. netropsis A-ICA and B. subtilis ALICA was evaluated using DPPH radical-scavenging activity, which exhibited a significant antioxidant potential with an IC50 value of 0.8 and 0.6 mg/mL. The 3D models of detected keratinases in both strains showed high similarity with subtilisin family. Further, the docking results clarified the importance of GSG and VVVFTP domains in B. subtilis and beta-keratin, respectively. The present study revealed the keratinolytic potential of S. netropsis A-ICA and B. subtilis ALICA in chicken feather degradation, which have potential application value and may be exploited as supplementary protein and antioxidant in animal feed formulations

Influence of monometallic and bimetallic phytonanoparticles on physiological status of mezquite

The present study was conducted to evaluate the impact of monometallic and bimetallic nanoparticles (NPs) of copper (Cu) and silver (Ag) from Justicia spicigera on the photochemical efficiency and phenol pattern of Prosopis glandulosa. In this study, the existence of localized surface plasmon resonance absorption associated with the nano-sized nature of Ag, Cu and Cu/Ag particles was confirmed by the presence of a single peak around 487, 585, and 487/580 nm respectively. Zeta potential and electrophoretic mobility were found to be 0.2 mV and 0.02 μmcm/(Vs) for synthesized NPs indicating less stability and thus tendency to agglomerate, and broad distribution of particles. Cu-NPs and Cu/Ag-NPs demonstrate that the dispersed phase is stable and has a minimum particle size at zeta potentials above –30 mV. Changes in phenolic compounds, total chlorophyll, and photochemical efficiency in leaves exposed to Ag, Cu and Cu/Ag phyto-nanoparticles were evaluated up to 72 hours. The results revealed that Ag-NP and Cu-NP from J. spicigera at 100 mg/L showed significant reduction in chlorophyll, epidermal polyphenol content and photochemical efficiency of P. glandulosa. In contrast, the application of bimetallic Cu/Ag-NP from J. spicigera showed a positive impact on physiological parameters of P. glandulosa after 72 h of exposure