Medio de cultivo convencional enriquecido con extractos de quinoa, amaranto y chía promueve el crecimiento de Staphylococcus aureus / Conventional culture media enriched with extracts of quinoa, amaranth and chia promotes the Staphylococcus aureus growth

La identificación bacteriana durante las infecciones microbiológicas es un aspecto crítico a la hora de escoger un tratamiento específico para evitar complicaciones del paciente o en algunos casos su muerte. Por ello, incrementar el crecimiento celular durante el diagnóstico clínico por cultivo bacteriano puede reducir el tiempo para determinar el patógeno que causa la enfermedad. En este trabajo, se utilizó el cultivo bacteriano como metodología y se evaluó el crecimiento de Staphylococcus aureus en un medio de cultivo convencional enriquecido con extractos de Chenopodium quinoa, Amaranthus caudatus y Salvia hispanica. Los resultados obtenidos muestran que estos extractos, a bajas concentraciones, tienen un efecto protector contra la citotoxicidad que se podría generar por el estrés oxidativo producto del metabolismo celular de las bacterias cultivadas in vitro e incrementan significativamente el crecimiento bacteriano. La adicción de estos extractos a los medios convencionales podría mejorar el crecimiento bacteriano durante un diagnóstico bacteriológico y reducir el tiempo de identificación del patógeno.

Increasing the bacterial growth rate reduces the time getting the bacteria identification. This is helpful to choose an accurate and quick therapeutic strategy during microbiological infections, avoiding illness complications or in some cases the death. Here, we used bacterial growth method and we evaluated the growth of Staphylococcus aureus including an extract of Chenopodium quinoa, Amaranthus caudatus and Salvia hispanica in the routine culture media. Results show that adding these extracts, at low concentrations, have a protective effect against the cytotoxicity that could be generated by the oxidative stress product of the cellular metabolism of the bacteria growing in vitro and significantly increase the bacterial growth. The addition of these extracts to conventional culture media could improve bacterial growth during a bacteriological diagnosis and to reduce the time of pathogen identification.

Effect of edible quinoa protein-chitosan based films on refrigerated strawberry (Fragaria × ananassa) quality

Background Strawberries are non-climacteric fruits with a low respiration rate, but are subject to serious fungal deterioration during postharvest handling. The edible coatings based on chitosan (CH), quinoa protein-chitosan (Q/CH) and quinoa protein-chitosan-sunflower oil (Q/CH/SO) may provide a solution to this problem. Thus, in this work CH, Q/CH and Q/CH/SO were elaborated and applied to fresh strawberries, and its effect on the strawberries shelf life during storage for 15 d was evaluated by mold and yeast count, fungal decay, carbon dioxide rate, physicochemical properties, and sensory evaluation. Results On all analysis days, the strawberries coated with the film-forming CH, Q/CH and Q/CH/SO solutions presented a significant lower amount of mold and yeast growth than the uncoated strawberries. Coated strawberries with Q/CH/SO decreased the CO2 emission rate by 60% compared to the uncoated strawberries. The color of the strawberries was not influenced by the films. There was no significant difference between the different coating groups and the uncoated group in the physicochemical parameters. Sensory analysis showed that the coating application retained the total sensorial quality. Conclusions Fresh strawberries coated with CH, Q/CH/SO and Q/CH edible films had longer shelf lives than uncoated fruits.

Caracterización bioquímica, fisicoquímica y funcional de turbot (Scophthalmus maximus) y estudio de sus modificaciones durante el almacenamiento a 4ºC / Biochemical, physicochemical and functional characterization of turbot (Scophthalmus maximus). Study of the changes occurring during the 4ºC storage

El turbot es un pez plano (Scophthalmus maximus), es uno de los peces que se adapta muy bien al cultivo intensivo en granja. Es necesario conocer sus propiedades fisicoquímicas-bioquímicas-tecnológicas y cómo éstas cambian durante su almacenamiento una vez que han sido cosechados. El objetivo de este estudio fue evaluar la composición centesimal, propiedades bioquímicas, fisicoquímicas y funcionales, y cómo se ven influidas por el almacenamiento a 4ºC durante 16 días. Se determinó su composición proximal, electroforesis en geles de poliacrilamida desnaturantes (PAGE-SDS), estabilidad térmica proteica a través de calorimetría diferencial de barrido (DSC). Se evaluó pH, nitrógeno básico volátil total (NBV-T), pérdida por goteo, textura, capacidad de retención de agua (CRA), emulsificación (CE) y gelificación (CG). El análisis proximal fue: humedad 76,3%; proteínas 19,6%; lípidos 2,71%; cenizas 1,3%. Se encontraron dos transiciones térmicas (DSC) a 47,5°C (miosina) y 76,9ºC (actina). PAGE-SDS mostraron perfiles correspondientes a proteínas miofibrilares y sarcoplasmáticas y durante el almacenamiento no se vieron alterados El pH cambió desde 5,9 a 6,6; las NBV-T variaron desde 20,0 a 39,5 mg NBVT/100 g músculo al día 16. CRA presentó valores de 10,5% y llegando al final a 58,1%, sin embargo no presentó CG. La CE y CRA aumentaron por el almacenamiento debido a cambios conformacionales de las proteínas. El esfuerzo de compresión fluctuó entre 111,2 a 106,0 N; el esfuerzo de cizalla fue disminuyendo en el tiempo de almacenamiento desde 148,6 a 95,2 N. La pérdida por goteo varió entre 1,7% a 2,5%. El estudio de almacenamiento refrigerado por 16 días, permitió concluir que el parámetro de frescura de NBV-T, sobrepasa el límite permitido de comercialización a los 14 días de almacenamiento, determinando de esa forma su vida útil.

The turbot (Scophthalmus maximus) is a kind of flatfish that is well adapted to intensive farm culture. After the harvest it is necessary to know the physicochemical, biochemical and technological properties and if during the refrigerated storage, changes of these properties are developed. The main objective of the study was the assessment of the proximal composition, the biochemical, physicochemical and functional properties, and how they are influenced during the 16 days storage at 4º C. Parameters such as centesimal composition, PAGE-SDS, and protein thermal stability through a DSC were carried out. pH, total volatile base-nitrogen (TVBN) dripping, texture, holding water capacity (WHC), emulsification (EC) and gelification (GC) were also determined. Results for the proximal composition were: humidity 76,3%; fat content 2,71%; proteins 19,6%; and ashes 1,3%. Two different thermal transitions at 47,5°C (myosin) and 76,9°C (actin) were observed. The PAGE-SDS showed profiles corresponding to myofibrilars and sarcoplasmatic proteins, which presented no changes during the storage. pH experimented an increase from 5,9 to 6,6; TVB-N showed a variation from 20,0 to 39,5 mg TVB-N/100 g of muscle at the day 16. The WHC started with a 10,5% and ended in 58,1%; no GC was observed. The increase of the EC and WHC during the storage was due to conformational changes of proteins. The compression force presented a fluctuation between 111,2 and 106,0 N and the shear strain decreased during the storage from 148,6 to 95,2 N. The dripping showed a variation between 1,7% and 2,5%. According to the results of the storage during 16 days at 4ºC, the NBV-T content determined a shelf life of 14 days.