Aurelio López-Malo

Se evaluó la capacidad antioxidante (CA) en subproductos de semillas de amaranto (Amaranthus hypochondriacus) de dos parcelas de cultivo, en función de tres métodos de extracción y dos disolventes, a tres concentraciones diferentes. En una primera etapa, se evaluó el efecto del método de extracción (homogeneización, ultrasonido de baja frecuencia y la combinación homogeneización-ultrasonido) y del disolvente de extracción (metanol o etanol, al 100%); en una segunda etapa, se evaluó el efecto de la concentración del disolvente de extracción (100%, 70% o 50%). La CA se determinó por inhibición del radical DPPH▪, expresándola en mg Equivalentes de Trolox (ET)/g materia seca; los compuestos fenólicos totales (FT) se determinaron mediante el ensayo de Folin–Ciocalteu, expresándolos como Equivalentes de Ácido Gálico (EAG)/g materia seca. Los compuestos antioxidantes se identificaron mediante cromatografía de gases acoplada a espectrometría de masas. Para la CA, no existe diferencia significativa (p>0,05) entre los métodos de extracción estudiados, mientras que si la hay (p0,05) entre disolventes al usarlos diluidos, sólo al emplearlos al 100%; mientras que para CA sí hay efecto de la concentración del disolvente, obteniendo mayores valores de CA al utilizar los disolventes al 50% (21,34 y 21,82 mg ET/g materia seca, con metanol y etanol, respectivamente). El análisis cualitativo de los extractos mostró la presencia de escualeno y 2,5-bis (1,1-dimetiletil) fenol como los principales compuestos con capacidad antioxidante.

En este trabajo se evaluaron la composición, algunas características físicas (densidad, índice de refracción y color), capacidad antioxidante (DPPH) y perfil de ácidos grasos de semillas de mostaza negra (Brassica nigra) y amarilla (Brassica alba), sus aceites y residuos de la extracción del aceite. La densidad de los aceites de mostaza negra y amarilla fue de 0,912 ± 0,01 y 0,916 ± 0,01 g/mL, respectivamente; y el índice de refracción fue de 1,4611 ± 0,01 y 1,4617 ± 0,01, respectivamente, no mostrando diferencias significativas (p>0,05) entre las dos mostazas. Los parámetros de color del aceite de semilla de mostaza negra y amarilla tienden hacia los tonos amarillos-verdosos y tonos amarillos-rojizos, respectivamente; respecto a la actividad antioxidante, se observó una variación desde 25 mg equivalentes de Trolox/100 g en el aceite de semilla de mostaza amarilla hasta 1,366 mg equivalentes de Trolox/100 g en la pasta residual de mostaza negra. El perfil de ácidos grasos de la semillas de mostaza negra muestran que el ácido graso predominante es el oleico (22,96%), seguido por linoleico (6,63%) y linolénico (3,22%), mientras que para la semilla de mostaza amarilla es el erúcico (6,87%), seguido por oleico (5,08%) y linoléico (1,87%).

Layered double hydroxides (LDHs) are functional anionic clays that belong to the family of two-dimensional (2D) materials. LDHs consist of positively charged brucite host layers separated by guest-exchangeable interlayer anions, which overall offer unique chemistry like flexible metal composition, ion-exchange capability, and structural reconstruction through memory effect property. These features provide exceptional opportunities for modulating the surface chemistry of LDHs through bottom-up synthetic strategies. By controlling chemical environment conditions and employing appropriate modulating agents, it is feasible to engineer morphology, introduce local structural imperfections such as oxygen and metal vacancies (Schottky defects), generate unsaturated coordination sites, and incorporate heteroatoms to enhance functionality. This review aims to examine recent advances in the chemical modulation and morphological control of LDHs. We summarize the principal bottom-up synthetic approaches and discuss how chemical doping, host–guest interactions, and defect engineering can be employed to tailor the structure and properties of LDHs. In particular, we emphasize the relationship between chemical modulation, morphology, and functional performance in environmental and energy-related applications. Specifically, we highlight recent progress in pollutant adsorption, degradation of organic contaminants, and hydrogen production, providing insights into the design of next-generation LDH-based materials for sustainable environmental and energy technologies.

Morphological control during the synthesis of metal–organic frameworks (MOFs) enables the tuning of their antimicrobial properties.

The aims of this study were to characterize clove leaf essential oil (CLEO), evaluate its antifungal activity in the vapor phase, and determine its effects on the physicochemical and sensory properties of semi-wholemeal bread. Also, the physicochemical properties of the CLEO and the bread were determined, as well as the sensory properties of the bread. The CLEO was analyzed by chemical composition, refractive index, color, viscosity, and density. The antifungal activity was tested in vapor phase against Aspergillus niger in vitro and on bread at different concentrations during 10 days of storage. The formulated bread contained 60% of wholemeal flour. The CLEO analysis identified α-caryophyllene (32.2%) and eugenol (25.7%) as the major compounds. The minimum inhibitory concentration (MIC) of CLEO in vitro against A. niger was 300 µL/Lair while on bread was 1250 µL/Lair. A contaminating mold identified as Penicillium chrysogenum was more resistant than A. niger, and its MIC was 1750 µL/Lair. The pH of bread was 5.7, the water activity was 0.882, and its moisture content of 32.1%. The sensory scores obtained (6.3–6.7) indicate that the CLEO-treated bread remains within the moderate acceptance range. While CLEO inhibits mold growth, its high concentration needed in bread diminishes aroma and flavor acceptance. Future research should optimize exposure time and concentration to enhance shelf life without affecting sensory qualities.

Designing multi-ingredient preservation systems is crucial for reducing the use of synthetic additives while maintaining food safety. This study evaluated the antimicrobial efficacy of ternary mixtures combining two natural antimicrobials (thymol, carvacrol, eugenol, citral, vanillin) and potassium sorbate (PS) against Listeria innocua and Salmonella Typhimurium at pH 4.5 and 5.5. The fractional inhibitory concentration index (FICI) and the total minimum inhibitory concentration (MIC) were determined to identify optimal synergistic combinations. Multivariate analysis, including Principal Component Analysis and Partial Least Squares (PLS) regression with standardized coefficients, was applied to decipher the relative impact and hierarchy of the predictor variables. At pH 4.5, concentrations of PS ≤ 64 ppm combined with any of the natural components resulted in higher synergistic mixtures (low FICI 0.318–0.378) for L. innocua. For Salmonella, only combinations of thymol, carvacrol, eugenol, and PS ≤ 32 ppm obtained the lowest FICI (0.252–0.344) at pH 4.5, while at pH 5.5, 128 ppm PS, thymol, and vanillin were required for a similar FICI (0.363). The PLS models revealed a distinct shift in variable importance between the synergistic index and the MIC. For the FICI model, mixture components exerted the primary influence; potassium sorbate displayed the highest predictive weight (standardized coefficient: +0.8736), followed by eugenol (+0.7757), carvacrol (+0.6206), and citral (+0.5119). This indicates that maximum synergism (lowest FICI) is constrained to lower fractional concentrations of natural compounds, thereby avoiding saturation of the cellular target site. Bacterial species (+0.2418) and pH (+0.3146) contributed less, indicating a homogeneous effect across the tested bacteria. For the total MIC model, potassium sorbate (+0.4701) and vanillin (+0.4492) regulated the antimicrobial quantity requirements. For the strains evaluated, the coefficients of the bacterial type in both models indicate that the ternary mixtures performed similarly. These findings demonstrate that integrating multivariate PLS modeling provides a robust framework for optimizing natural-synthetic antimicrobial blends, significantly reducing dependence on potassium sorbate through tailored synergism.

Cottage cheese is a promising matrix for delivering probiotic microorganisms due to its buffering capacity, high moisture content, and consumer acceptance. In this study, a probiotic cottage cheese incorporating Lactobacillus acidophilus LA-5 was developed and evaluated against a control formulation and commercial products. Physicochemical properties, probiotic viability, acidification kinetics, and sensory acceptance were assessed during refrigerated storage. The formulation consistently maintains viable probiotic counts above 108 CFU/g for 24 days, meeting the minimum threshold for health benefits. Although gradual post-acidification was observed, changes in pH (a decrease ≈ of 0.79 pH units) and titratable acidity (from 0.32 to 0.46%) did not significantly compromise probiotic survival, indicating a protective effect of the cheese matrix. Sensory evaluation, including triangular discrimination and hedonic testing, demonstrated that incorporating probiotics did not significantly affect consumer perception (p > 0.05), with overall acceptability scores (7.20) comparable to those of the control (7.45) and commercial cheeses (6.95-7.45). These findings highlight cottage cheese’s potential as an effective probiotic carrier, delivering microbial doses while maintaining sensory and technological qualities. This study supports the development of functional dairy foods as alternatives to dietary supplements for gut health and well-being.

This work aimed to assess the effect of pH [3.0 and 3.6] and water activity [aw; 0.99, 0.97, 0.96, or 0.94] on alginate beads formulated with apple juice on the viability of Lactiplantibacillus plantarum 299v, Limosilactobacillus reuteri NRRLB-14171, Lactobacillus acidophilus NRRLB-4495, or Lacticaseibacillus casei NRRLB-1922 during the encapsulation process and after 7 days of refrigerated storage. In addition, sensory tests of alginate beads formulated with apple juice and L. reuteri were conducted. The aw did not affect Lactobacillus viability, whereas pH had only a slight effect on their survival. Encapsulation yields exceeded 90% across all tested conditions and bacteria. After 7 days of storage at 5 °C, <1 log10 CFU/g was reduced in Lactobacillus counts. Beads formulated with apple juice at pH 3.6 and aw of 0.97 were the best accepted by the panelists.

1. Dielectric properties (DP) of foods are the physical properties of food materials that are exhibited when exposed to microwaves (MW) or radiofrequency (RF) waves (Metaxas & Meredith, 1993). The ...