Evaluación de un recubrimiento comestible a base de agar y ácido cítrico

The performance of an edible coating based on agar and citric acid over potato (Solanum tuberosum) was evaluated. The potatoes were tried by immersion with solutions of Agar (A), Agar-Citric acid (AC), Agar- Glycerol (AG), and a mixture of the three (ACG). AC based film showed the lowest thickness values and rate of water vapor transmission. Coating the fruit with AC reduced 1.57 times weight loss compared to the control. Moreover, AC showed higher brightness values, chrome, kept the sensory characteristics and reduced the presence of potato sprouts after 6 days at 20 °C. In scanning electron microscopy no substantial morphological changes were observed in potatoes with the applied treatments. The results show that the formulation based on agar and citric acid (AC) had the characteristics of semipermeable film and edible coating.Se evaluó el desempeño de un recubrimiento comestible a base de agar y ácido cítrico empleando como modelo de prueba papa fresca (Solanum tuberosum). Esta fue tratada por inmersión con soluciones de agar (A), agar-ácido cítrico (AC), agar-glicerol (AG) y la mezcla de los tres (ACG). La película con base AC presentó los valores menores de grosor y velocidad de transmisión al vapor de agua. El recubrimiento del fruto con AC redujo 1.57 veces la pérdida de peso con respecto al testigo. Además, presentó valores mayores de luminosidad, croma, mantuvo las características sensoriales y redujo la presencia de brotes en papa después de 6 días a 20 °C. La microscopía electrónica de barrido no reveló cambios morfológicos substanciales en el producto con los tratamientos aplicados. Los resultados demuestran que la formulación a base de agar y ácido cítrico (AC) presentó las características de una película semipermeable y de recubrimiento comestible

Materiales compuestos elaborados partir de desechos de cuero

Se estudiaron las características físicas y las propiedades mecánicas de varios materiales compuestos elaborados a partir de desperdicios de cuero y dos resinas comerciales de policloruro de vinilo, que constituyen la matriz polimérica

Materiales compuestos elaborados partir de desechos de cuero

In This experiment the physical characteristics and mechanical properties of different composite materials produced from leather waste generated by the shoe industry in León, Guanajuato, México, and two polyvinyl chloride (PVC) resins were determined. Two of the physical characteristics of these composites are: high water absorption rates without significant increase in thickness and an excellent resistance of friction under humid conditions, superior to that of synthetic materials.The mechanical properties of composites produced from transparent PVC are: a higher resistance to tension, compared with the other PVC resin. In conclusion, the composites show very promising perspectives for a possible use in the production of leather substitutes and other synthetic materials in the shoe industry. Se estudiaron las características físicas y las propiedades mecánicas de varios materiales compuestos elaborados a partir de desperdicios de cuero y dos resinas comerciales de policloruro de vinilo, que constituyen la matriz polimérica

Anti-Herpes simplex virus (HSV-1) activity and antioxidant capacity of carrageenan-rich enzymatic extracts from Solieria filiformis (Gigartinales, Rhodophyta)

International audienc

la Evaluación de películas comestibles de quitosano, agar y tomillo para mantener la calidad de frutos de aguacate ‘Hass’ durante su almacenamiento

In this work, edible films (PCs) based on chitosan (Q), agar (A) and thyme oil (T) were prepared in four different formulations (Q, A, QA and QAT), and their mechanical properties (tension and elongation at break) and water vapor permeability were evaluated. Infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) were also performed. The QA and QAT PCs stood out for their tensile strength, transparency, water vapor transmission rate and permeance, as well as the highest antioxidant activity. The effect of the application of the edible coatings (RCs) of QA and QAT on the quality of 'Hass' avocado fruit was evaluated during 13 days of storage at 25 °C. The following variables were evaluated periodically: weight loss, respiration rate, ethylene production, visual appearance, and rotting. The application of RCs to the fruit reduced their weight loss and extended their shelf life. The RCs gave the fruit a barrier to water vapor, reducing weight loss by 40 with respect to the control. In addition, the incidence of fruit rots was reduced.En este trabajo se elaboraron películas comestibles (PCs) a base de quitosano (Q), agar (A) y tomillo (T), en cuatro diferentes formulaciones (Q, A, QA y QAT). A las PCs se les evaluaron propiedades mecánicas (tensión y elongación a la ruptura), propiedades estructurales (espectroscopía de infrarrojo por FTIR), propiedades térmicas (análisis termogravimétrico), propiedades de transporte (permeabilidad al vapor de agua) y análisis morfológico (microscopía electrónica de barrido). Las PCs de QA y QAT destacaron por su resistencia a la tensión, transparencia, velocidad de transmisión al vapor de agua y permeancia, así como la mayor capacidad antioxidante. Se evaluó el efecto de la aplicación de los recubrimientos comestibles (RCs) de QA y QAT en la calidad de frutos de aguacate “Hass” durante 13 días de almacenamiento a 25 °C. Se evaluaron periódicamente en los frutos las variables de pérdida de peso, tasa de respiración, producción de etileno, apariencia visual y pudriciones. La aplicación de los RCs al fruto redujo su pérdida de peso y extendió su vida de anaquel. Los RCs les confirieron a los frutos una barrera al vapor de agua, reduciendo la pérdida de peso en 40%. Así mismo, se disminuyó la incidencia de pudriciones de los frutos

Bioactive Compounds in Extracts from the Agro-Industrial Waste of Mango

Mango by-products are important sources of bioactive compounds generated by agro-industrial process. During mango processing, 35–60% of the fruit is discarded, in many cases without treatment, generating environmental problems and economic losses. These wastes are constituted by peels and seeds (tegument and kernel). The aim of this review was to describe the extraction, identification, and quantification of bioactive compounds, as well as their potential applications, published in the last ten years. The main bioactive compounds in mango by-products are polyphenols and carotenoids, among others. Polyphenols are known for their high antioxidant and antimicrobial activities. Carotenoids show provitamin A and antioxidant activity. Among the mango by-products, the kernel has been studied more than tegument and peels because of the proportion and composition. The kernel represents 45–85% of the seed. The main bioactive components reported for the kernel are gallic, caffeic, cinnamic, tannic, and chlorogenic acids; methyl and ethyl gallates; mangiferin, rutin, hesperidin, and gallotannins; and penta-O-galloyl-glucoside and rhamnetin-3-[6-2-butenoil-hexoside]. Meanwhile, gallic acid, ferulic acid, and catechin are reported for mango peel. Although most of the reports are at the laboratory level, they include potential applications in the fields of food, active packaging, oil and fat, and pharmaceutics. At the market level, two trends will stimulate the industrial production of bioactive compounds from mango by-products: the increasing demand for industrialized fruit products (that will increase the by-products) and the increase in the consumption of bioactive ingredients

Production of Biocomposites Using Different Pre-treated Cut Jute Fibre and Polylactic Acid Matrix and Their Properties

The extensive use of petroleum-based plastics has led to serious environmental problems worldwide. A viable alternative is to replace these polymers with those that are biodegradable. Polylactic acid (PLA) is a biodegradable polymer with properties that are similar to petroleum-based polymers. However, it has some drawbacks such as brittleness, poor impact strength, low heat distortion, and poor difficulties in thermal stability during processing. In this study, we describe the use of modified jute fibres to reinforce the PLA polymer matrix in order to improve its adhesion. Biocomposites of PLA and cut jute fibres (CJF) were prepared by extrusion. The CJF were modified using three different physical and chemical pretreatments (alkaline, maleic anhydride functionalization, and gamma irradiation). The results showed improvement in the mechanical, thermal, structural, and morphological properties of PLA biocomposites with 10% wt. CJF that were subjected to gamma irradiation at 50 kGy. The biocomposites developed could be used for rigid food packaging and are a good alternative for reducing domestic dependence on petroleum-based thermoplastics

Functional and antibacterial characterization of electrospun nanofiber membranes made of chitosan and polyvinyl alcohol

The development of nanomaterials with improved functional characteristics is a priority because of their applicability in medicine. Therefore, in this study, chitosan nanofiber membranes were electrospun with polyvinyl alcohol supplemented with carboxymethyl cellulose and pectin. The membrane characterization included identifying the functional groups of each polymer, the surface appearance, and the absorption capacity of aqueous media, simulating the exudates of skin diseases. Membrane weight loss was close to 50 % during the first day, and they preserved their integrity throughout the study. The mechanical characteristics demonstrated that the membranes with adjuvants are flexible and tough. The rigidity of the membranes was between 10.49 MPa and 22.65 MPa, and this rigidity decreased with the addition of chitosan and pectin. With chitosan, the elongation at break (8.25 %) was higher but the elastic modulus (450.78 MPa) was lower than those recorded with the other polymers. The effect against Staphylococcus aureus occurs due to chitosan and only by contact. In particular, an inhibition zone increased with the addition of chitosan (178.21 mm2). However, carboxymethyl cellulose showed the least shrinkage (4.4 %). Therefore, it is possible to produce nanofibers to make chitosan and polyvinyl alcohol membranes with improved functional characteristics by the addition of adjuvant agents as an alternative to other skin healing materials