Insights on the effectiveness of pneumatic and ultrasonic atomization in combination with UVC light for processing of fruit juices.

This study evaluated the effectiveness of spraying juices, during shortwave ultraviolet irradiation (UVC) treatments as an alternative to promote more contact area, by means of ultrasonic atomization (UA) and pneumatic atomization (PA). Four juices with dissimilar physical characteristics were processed to assess the effect of suspended solids and turbidity. Antioxidant activity, anthocyanins, ascorbic acid, and inactivation of Saccharomyces cerevisiae inoculated in the juices were evaluated. Five decimal reduction cycles were reached after two passes of orange or grapefruit juice through the UVC + UA arrangement. On the other hand, five decimal reduction cycles were achieved after three passes in the UVC + PA arrangement. Losses of 11% and 14% of ascorbic acid were observed in orange and grapefruit juice, respectively, while anthocyanin content presented losses of 50% and antioxidant activity decreased by 40% for pomegranate and blueberry juice, correspondingly.

Fungal inactivation on Mexican corn tortillas by means of thyme essential oil in vapor-phase.

Antifungal activity of thyme (Thymus vulgaris) essential oil (EO) in vapor-phase was tested against representative fungi in corn tortillas. The chemical composition of studied EO was analyzed by gas chromatography-mass spectroscopy, and its major components were linalool, thymol, and p-cymene. The antifungal activity was evaluated by determining the growth of Aspergillus niger or Penicillium expansum after exposure to EO vapors. The in vitro minimum inhibitory concentration (MIC) of the EO was determined by the inverted lid technique, while in situ MIC was determined on the corn tortillas inside an airtight container. The MICs obtained ranged from 160 to 200 µL of thyme EO/Lof air for in vitro conditions and 550-850 µL of the EO/Lof air in corn tortillas. The modified Gompertz model adequately described in vitro mold growth curves. Thyme EO was effective in preventing or significantly delaying growth of the contaminating molds on corn tortillas.

Essential oils in vapor phase as alternative antimicrobials: A review.

The antimicrobial effectiveness of essential oils (EOs) against many foodborne microorganisms when applied by direct contact has been extensively demonstrated. However, the vapor phase and volatile components present in EOs have not been thoroughly investigated; there are a small number of published reports on the antimicrobial activity of some EOs and a few of their components against selected microorganisms. It is well known that the antimicrobial activity of EOs depends mainly on their chemical composition. It is also important; however, to understand the volatility of these compounds as well as the methodologies used to evaluate the antimicrobial effectiveness of their vapor phase. This review focuses on recent research regarding the chemical composition of EOs, their biological activity and mechanisms of action, the antimicrobial activity of EOs in the vapor phase, the different techniques that have been proposed to evaluate the antimicrobial effects of EOs in the vapor phase, and actual and potential applications of EOs in the vapor phase. Although there is still no standard methodology for determining the activity of EOs in the vapor phase, results reported thus far are encouraging and suggest possible applications in food preservation.

High-Intensity Light Pulses To Inactivate Salmonella Typhimurium on Mexican Chia (Salvia hispanica L.) Seeds.

Chia seeds provide a suitable environment for microorganisms. However, it is difficult to disinfect these seeds with water and/or chemical disinfectant solutions because the mucilage in the seeds can absorb water and consequently form gels. High-intensity light pulses (HILP) is one of the most promising emerging technologies for inactivating microorganisms on surfaces, in clear liquids and beverages, and on solid foods. The aim of this work was to evaluate the effect of HILP on Salmonella Typhimurium in culture medium (in vitro tests) and inoculated onto chia seeds (in vivo tests). HILP was effective against Salmonella Typhimurium under both conditions: 8 s of treatment (10.32 J/cm2) resulted in a 9-log reduction during in vitro tests, and 15 s of treatment (19.35 J/cm2) resulted in a 4-log reduction on the inoculated chia seeds. Salmonella Typhimurium inactivation kinetics were accurately described using the Weibull model (R2 > 0.939). These results indicate that the use of HILP for microbial inactivation on seeds could generate products suitable for human consumption.

Antimicrobial, Cytotoxic, and Anti-Inflammatory Activities of Pimenta dioica and Rosmarinus officinalis Essential Oils.

Essential oils (EOs) are natural products composed of a mixture of volatile and aromatic compounds extracted from different parts of plants that have shown antimicrobial activities against pathogens. In this study, EOs extracted from Pimenta dioica (Myrtaceae) and Rosmarinus officinalis (Lamiaceae) were assessed for their antimicrobial activities using a panel of pathogenic Gram-positive, Gram-negative, and fungal strains. The antimicrobial activity was measured by the minimal inhibitory concentration required for the growth inhibition of the microorganisms. The cytotoxicity of the EOs was tested ex vivo using the model of human-derived macrophage THP-1 cells. In addition, an inflammatory response was evaluated using the anti-inflammatory cytokine IL-10 and the proinflammatory cytokines IL-6 and TNF-α. Results showed that both EOs had antimicrobial activity and different pathogens were exposed to concentrations ranging between 600 and 2000 µg/mL. In addition, the EOs showed no inflammatory activity when exposed to human macrophages, but a potent anti-inflammatory activity was measured when the oil from Rosmarinus officinalis was exposed to macrophages. This study demonstrates that the use of EOs is an effective alternative for pathogenic bacterial and fungal control, alone or in combination with antibiotic therapy. Moreover, the oil extracted from Rosmarinus officinalis could be used as potent anti-inflammatory agent.

Complex Coacervation Between Gelatin and Chia Mucilage as an Alternative of Encapsulating Agents.

Complex coacervation between gelatin type B (GE) and chia mucilage (ChM) was studied. GE-ChM were mixed at mass ratios of 1:1, 2:1, 3:1, 4:1, and 1:2 in a pH range of 1.50 to 5.00, maintaining a total solid concentration of 0.2% (w/w), using turbidity and viscosity tests to obtain the highest yield of complex coacervates. To characterize the complex coacervates, morphology and Fourier-transform infrared spectroscopy (FTIR) were determined. The optimum yield for complex coacervation was achieved with a GE-ChM mass ratio of 2:1 and pH value of 3.6. The critical pH values associated with the formation of soluble (pHc ) and insoluble (pHɸ1 ) complexes, and complete dissociation (pHɸ2 ) at the optimum GE-ChM ratio were found to be 4.50, 4.10, and 2.00, respectively. It was observed that increasing the mass ratio of GE or ChM, the yield of complex coacervates decreased; the higher yields were obtained with the proportions of 2:1 and 1:1 with values of 68.25 ± 0.05% and 61.04 ± 0.05%, respectively. Capsules formed at mass ratios of 1:1, 2:1, and 3:1, had the characteristic grape agglomerate shape for complex coacervates. Further characterization with scanning electron microscopy (SEM) showed a spherical shape for capsules. FTIR spectrum of complex coacervates at optimum conditions had a combination of bands corresponding to GE and ChM, suggesting an interaction between GE-ChM during the formation of complex coacervates. Therefore, complex coacervates between GE-ChM can be formed, and could be used as an alternative as encapsulating agents to be applied in the food industry. PRACTICAL APPLICATION: Complex coacervation is a technique that is being studied in several applications in the food industry. However, studies are still being made to explore different possibilities of natural sources to be used in complex coacervation. This study showed that the combination of gelatin and chia mucilage may be an alternative as encapsulating agents for complex coacervation to be applied in the food industry.

Evaluation of the efficiency of allspice, thyme and rosemary essential oils on two foodborne pathogens in in-vitro and on alfalfa seeds, and their effect on sensory characteristics of the sprouts.

Seeds are usual source of contamination and their sprouts are commonly associated foodborne illness. Therefore, the aim of this study was to evaluate the antibacterial vapor phase efficiency of allspice, thyme and rosemary essential oils on two foodborne pathogens in in vitro and on alfalfa seeds, including the chemical profile of the tested EOs and their effect on the sensory characteristics of the sprouts. Antibacterial activity was determined through the minimal inhibitory concentration (MIC) of EOs in vapor phase to inhibit the growth of Listeria monocytogenes and Salmonella Typhimurium in culture media and on alfalfa seeds. Also, the germination and the effect on sensory characteristics of the sprouts were determined. Thyme EO was the most effective of the tested EOs on culture media and on alfalfa seeds, against both bacteria. When rosemary EO was tested against L. monocytogenes in alfalfa seeds, the MIC (4.0 mL/Lair) was higher, compared to the one obtained in culture media (2.7 mL/Lair). But when this EO was tested against S. Typhimurium, the MIC in alfalfa seeds was lower than in culture media (11.7 vs 13.3 mL/Lair). Allspice EO resulted more effective against both bacteria in alfalfa seeds (6.0 mL/Lair for L. monocytogenes and 6.7 mL/Lair for S. Typhimurium), compared to culture media (12.0 mL/Lair for L. monocytogenes and 13.3 mL/Lair for S. Typhimurium). Vapor phase EOs MICs resulted in significant (p ≤ 0.05) decreases of L. monocytogenes and S. Typhimurium counts compared to the control. There also was a significant (p ≤ 0.05) difference between systems (in vitro or on alfalfa seeds) despite the microorganism or the evaluated EO. Treatment alfalfa seed with vapor phase EOs, did not affect the seed germination. Sensory acceptability of the sprouts, obtained of treated seeds, did not were significant (p ≥ 0.05) different of the sprouts obtained from the non-treated seeds.

Growth modeling to control (in vitro) Fusarium verticillioides and Rhizopus stolonifer with thymol and carvacrol / Modelización del crecimiento in vitro para controlar Fusarium verticillioides y Rhizopus stolonifer con timol y carvacrol

The aim of this study was to evaluate the antifungal activity (in vitro) of thymol and carvacrol alone or in mixtures against Fusarium verticillioides and Rhizopus stolonifer, and to obtain primary growth models. Minimal inhibitory concentration (MIC) was evaluated with fungal radial growth with thymol or carvacrol concentrations (0-1600mg/l). Mixtures were evaluated using concentrations below MIC values. Radial growth curves were described by the modified Gompertz equation. MIC values of carvacrol were 200mg/l for both fungi. Meanwhile, MIC values of thymol were between 500 and 400mg/l for F verticillioides and R. stolonifer, respectively. A synergistic effect below MIC concentrations for carvacrol (100mg/l) and thymol (100-375 mg/l) was observed. Significant differences (p <0.05) between the Gompertz parameters for the antimicrobial concentrations and their tested mixtures established an inverse relationship between antimicrobial concentration and mycelial development of both fungi. Modified Gompertz parameters can be useful to determine fungistatic concentrations.

El objetivo de este trabajo fue evaluar la actividad antifúngica in vitro del timol y del carvacrol, solos o en mezclas, contra Fusarium verticillioides y Rhizopus stolonifer, y obtener modelos primarios de crecimiento. Se evaluó la concentración inhibitoria mínima (CIM) con el crecimiento radial, se ensayaron concentraciones de timol y carvacrol de 0 a 1.600 mg/l. Las mezclas se evaluaron utilizando concentraciones por debajo de los valores de CIM. Las curvas de crecimiento radial fueron descritas por la ecuación de Gompertz modificada. Se obtuvieron los siguientes valores de CIM: carvacrol, 200 mg/l para las 2 especies; timol, 500 mg/l y 400 mg/l para F. verticillioides y R. stolonifer, respectivamente. Se observó un efecto sinèrgico a concentraciones inferiores a las CIM para el carvacrol (100mg/l) y el timol (100-375 mg/l). Hubo diferencias significativas (p <0,05) entre los parámetros de crecimiento de Gompertz; se estableció que existe una relación inversa entre la concentración de los antimicrobianos y el desarrollo del micelio de ambos hongos.

Penicillium expansum Inhibition on Bread by Lemongrass Essential Oil in Vapor Phase.

The antimicrobial activity of lemongrass (Cymbopogon citratus) essential oil (EO) in the vapor phase on the growth of Penicillium expansum inoculated on bread was evaluated, followed by a sensory evaluation of the bread's attributes after EO exposure. The lemongrass EO was extracted from dry leaves of lemongrass by microwave-assisted steam distillation. The chemical composition of the lemongrass EO was determined using a gas chromatograph coupled to a mass spectrometer. The refractive index and specific gravity of the EO were also determined. Bread was prepared and baked to reach two water activity levels, 0.86 or 0.94, and then 10 µL of P. expansum spore (106 spores per mL) suspension was inoculated on the bread surface. Concentrations of lemongrass EO were tested from 125 to 4,000 µL/Lair, whereas mold radial growth was measured for 21 days. For sensory evaluation, breads were treated with lemongrass EO vapor at 0, 500, or 1,000 µL/Lair for 48 h and tested by 25 untrained panelists. The EO yield was 1.8%, with similar physical properties to those reported previously. Thirteen compounds were the main components in the EO, with citral being the major compound. P. expansum was inhibited for 21 days at 20°C with 750 µL of EO/Lair, and its inhibition increased with increasing concentrations of EO. Sensory acceptance of bread exposed to vapor concentrations of 500 or 1,000 µL of EO/Lair or without EO was favorable; similar and no significant differences (P > 0.05) were observed among them.

Growth modeling to control (in vitro) Fusarium verticillioides and Rhizopus stolonifer with thymol and carvacrol.

The aim of this study was to evaluate the antifungal activity (in vitro) of thymol and carvacrol alone or in mixtures against Fusarium verticillioides and Rhizopus stolonifer, and to obtain primary growth models. Minimal inhibitory concentration (MIC) was evaluated with fungal radial growth with thymol or carvacrol concentrations (0-1600mg/l). Mixtures were evaluated using concentrations below MIC values. Radial growth curves were described by the modified Gompertz equation. MIC values of carvacrol were 200mg/l for both fungi. Meanwhile, MIC values of thymol were between 500 and 400mg/l for F. verticillioides and R. stolonifer, respectively. A synergistic effect below MIC concentrations for carvacrol (100mg/l) and thymol (100-375mg/l) was observed. Significant differences (p<0.05) between the Gompertz parameters for the antimicrobial concentrations and their tested mixtures established an inverse relationship between antimicrobial concentration and mycelial development of both fungi. Modified Gompertz parameters can be useful to determine fungistatic concentrations.

Description of Aspergillus flavus growth under the influence of different factors (water activity, incubation temperature, protein and fat concentration, pH, and cinnamon essential oil concentration) by kinetic, probability of growth, and time-to-detection models.

A Box-Behnken design was used to determine the effect of protein concentration (0, 5, or 10g of casein/100g), fat (0, 3, or 6g of corn oil/100g), aw (0.900, 0.945, or 0.990), pH (3.5, 5.0, or 6.5), concentration of cinnamon essential oil (CEO, 0, 200, or 400µL/kg) and incubation temperature (15, 25, or 35°C) on the growth of Aspergillus flavus during 50days of incubation. Mold response under the evaluated conditions was modeled by the modified Gompertz equation, logistic regression, and time-to-detection model. The obtained polynomial regression models allow the significant coefficients (p<0.05) for linear, quadratic and interaction effects for the Gompertz equation's parameters to be identified, which adequately described (R2>0.967) the studied mold responses. After 50days of incubation, every tested model system was classified according to the observed response as 1 (growth) or 0 (no growth), then a binary logistic regression was utilized to model A. flavus growth interface, allowing to predict the probability of mold growth under selected combinations of tested factors. The time-to-detection model was utilized to estimate the time at which A. flavus visible growth begins. Water activity, temperature, and CEO concentration were the most important factors affecting fungal growth. It was observed that there is a range of possible combinations that may induce growth, such that incubation conditions and the amount of essential oil necessary for fungal growth inhibition strongly depend on protein and fat concentrations as well as on the pH of studied model systems. The probabilistic model and the time-to-detection models constitute another option to determine appropriate storage/processing conditions and accurately predict the probability and/or the time at which A. flavus growth occurs.

Antimicrobial activity of whey protein films supplemented with Lactobacillus sakei cell-free supernatant on fresh beef.

The aim of this work was to evaluate the antimicrobial activity of whey protein isolate (WPI) films supplemented with Lactobacillus sakei NRRL B-1917 cell-free supernatant on beef inoculated with Escherichia coli ATCC 25922 or Listeria monocytogenes Scott A; additionally, sensory evaluation was performed on wrapped beef cubes. Supernatant concentrates were obtained from Lb. sakei cultures in MRS broth after centrifugation, filtering, and freeze-drying. Films were prepared with WPI (3% w/w), alginate (0.625% w/w), rehydrated supernatant (18 mg/ml), and glycerol. Films were used to wrap beef cubes inoculated with ≈103 CFU/g E. coli or L. monocytogenes. Sensory evaluation was carried out on grilled beef wrapped or not with the studied antimicrobial films. During refrigerated storage, antimicrobial films reduced 1.4 log10 CFU/g of L. monocytogenes after 120 h, while E. coli decreased 2.3 log10 CFU/g after 36 h. Grilled beef wrapped with antimicrobial film was well accepted by panelists, besides scores evidenced no significant differences (p > 0.05) between wrapped and unwrapped beef.

Antimicrobial Activity of Individual and Combined Essential Oils against Foodborne Pathogenic Bacteria.

The antimicrobial activities of essential oils from Mexican oregano (Lippia berlandieri Schauer), mustard (Brassica nigra), and thyme (Thymus vulgaris) were evaluated alone and in binary combinations against Listeria monocytogenes, Staphylococcus aureus, or Salmonella Enteritidis. Chemical compositions of the essential oils were analyzed by gas chromatography-mass spectrometry. The MICs of the evaluated essential oils ranged from 0.05 to 0.50% (vol/vol). Mustard essential oil was the most effective, likely due to the presence of allyl isothiocyanate, identified as its major component. Furthermore, mustard essential oil exhibited synergistic effects when combined with either Mexican oregano or thyme essential oils (fractional inhibitory concentration indices of 0.75); an additive effect was obtained by combining thyme and Mexican oregano essential oils (fractional inhibitory concentration index = 1.00). These results suggest the potential of studied essential oil mixtures to inhibit microbial growth and preserve foods; however, their effect on sensory quality in selected foods compatible with their flavor needs to be assessed.

Estimation of Listeria monocytogenes survival during thermoultrasonic treatments in non-isothermal conditions: Effect of ultrasound on temperature and survival profiles.

Estimation of Listeria monocytogenes survival during thermoultrasonic treatments in non-isothermal conditions was determined considering an increment from 45 to 70 °C, assessing the adequacy of predictions through experimental data obtained in laboratory media model systems. In order to characterize the sonication effect on the survival pattern, observed behavior was compared to that obtained when only thermal treatment was applied. A noticeable impact on L. monocytogenes survival in non-isothermal conditions was observed when heat is combined with ultrasound, since the sonication effect modifies not only the temperature profile, but also the dynamic survival pattern. It was observed that both treatments were able to achieve a reduction of 5.5 log cycles of the initial population, although the inactivation temperature and the required time to reach such temperature were lower for thermoultrasonic treatments than for thermal treatments. Furthermore, as the temperature dependent parameters required to estimate the dynamic responses in non-isothermal treatments were initially determined from isothermal conditions, the sonication effect on these parameters and its implications for dynamic estimations, which are closely related to the nonlinearity of the systems, were also addressed; for thermal treatments, obtained isothermal curves were properly described by the Weibull model and first order kinetics, while for thermoultrasonication treatments a clear non-linear behavior was observed and only the Weibullian model was able to adequately describe the inactivation pattern.

Características físicas y antioxidantes de semillas y productos de mostaza negra (Brassica nigra) y amarilla (Brassica alba) / Physical and antioxidant characteristics of black (Brassica nigra) and yellow mustard (Brassica alba) seeds and their products

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%).

The composition, some physical properties (density, refraction index, and color), antioxidant capacity (DPPH), and fatty acid profile of seeds of black (Brassica nigra) or yellow mustard (Brassica alba) were evaluated, as well as for their oils and residues from oil extraction. Density of the black and yellow mustard oils were 0.912 ± 0.01 and 0.916 ± 0.01 g/mL, respectively; their refraction indexes were 1.4611 ± 0.01 and 1.4617 ± 0.01, respectively; being not significantly different (p>0.05) between two mustards. Color parameters of the black and yellow mustard oils presented greenish-yellow tones and reddish-yellow tones, respectively; regarding antioxidant activities, these ranged from 25 mg equivalents of Trolox/100 g in the yellow mustard oil to 1,366 mg equivalents of Trolox/100 g in the residues from oil extraction of black seed mustard. The fatty acid profile of the black mustard seed revealed that its predominant fatty acid is oleic (22.96%), followed by linoleic (6.63%) and linolenic (3.22%), whereas for yellow mustard seed the major fatty acid is erucic (6.87%), followed by oleic (5.08%) and linoleic (1.87%) acids.

Composition, diffusion, and antifungal activity of black mustard (Brassica nigra) essential oil when applied by direct addition or vapor phase contact.

In this study, we characterized the essential oil (EO) of black mustard (Brassica nigra) and quantified its antimicrobial activity, when applied by direct contact into the liquid medium or by exposure in the vapor phase (in laboratory media or in a bread-type product), against the growth of Aspergillus niger, Aspergillus ochraceus, or Penicillium citrinum. Allyl-isothiocyanate (AITC) was identified as the major component of B. nigra EO with a concentration of 378.35 mg/ml. When B. nigra EO was applied by direct contact into the liquid medium, it inhibited the growth of A. ochraceus and P. citrinum when the concentration was 2 µl/ml of liquid medium (MIC), while for A. niger, a MIC of B. nigra EO was 4 µl/ml of liquid medium. Exposure of molds to B. nigra EO in vapor phase showed that 41.1 µl of B. nigra EO per liter of air delayed the growth of P. citrinum and A. niger by 10 days, while A. ochraceus growth was delayed for 20 days. Exposure to concentrations ≥ 47 µl of B. nigra EO per liter of air (MIC) inhibited the growth of tested molds by 30 days, and they were not able to recover after further incubation into an environment free of EO (fungicidal effect). Adsorbed AITC was quantified by exposing potato dextrose agar to B. nigra EO in a vapor phase, exhibiting that AITC was retained at least 5 days when testing EO at its MIC or with higher concentrations. Mustard EO MIC was also effective against the evaluated molds inhibiting their growth for 30 days in a bread-type product when exposed to EO by vapor contact, demonstrating its antifungal activity.

[Physical and antioxidant characteristics of black (Brassica nigra) and yellow mustard (Brassica alba) seeds and their products]. / Características físicas y antioxidantes de semillas y productos de mostaza negra (Brassica nigra) y amarilla (Brassica alba).

The composition, some physical properties (density, refraction index, and color), antioxidant capacity (DPPH), and fatty acid profile of seeds of black (Brassica nigra) or yellow mustard (Brassica alba) were evaluated, as well as for their oils and residues from oil extraction. Density of the black and yellow mustard oils were 0.912 ± 0.01 and 0.916 ± 0.01 g/mL, respectively; their refraction indexes were 1.4611 ± 0.01 and 1.4617 ± 0.01, respectively; being not significantly different (p > 0.05) between two mustards. Color parameters of the black and yellow mustard oils presented greenish-yellow tones and reddish-yellow tones, respectively; regarding antioxidant activities, these ranged from 25 mg equivalents of Trolox/100 gin the yellow mustard oil to 1,366 mg equivalents of Trolox/100 g in the residues from oil extraction of black seed mustard. The fatty acid profile of the black mustard seed revealed that its predomipant fatty acid is oleic (22.96%), followed by linoleic (6.63%) and linolenic (3.22%), whereas foryellow mustard seed the major fatty acid is erucic (6.87%), followed by oleic (5.08%) and linoleic (1.87%) acids.

Capacidad antioxidante de subproductos de semillas de amaranto (Amaranthus hypochondriacus) / Antioxidant capacity of byproducts from amaranth (Amaranthus hypochondriacus) seeds

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 (p<0,05) entre disolventes (3,39 y 1,28 mg ET/g materia seca, con metanol y etanol, respectivamente). Para FT, no hay diferencia significativa (p>0,05) 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.

The antioxidant capacity (CA) of byproducts from amaranth (Amaranthus hypochondriacus) seeds from two harvest parcels as a function of three extraction methods and two solvents was evaluated. On a first stage the effect of extraction method (homogenization, low frequency ultrasound, or the combination homogenization-ultrasound) and extraction solvent (methanol or ethanol, 100%) were evaluated; on a second stage, the effect of extraction solvent concentration (100%, 70%, or 50%) was evaluated. CA was determined by DPPH▪ inhibition, which was expressed as mg Equivalents of Trolox (ET)/g dry matter (DM). Total Phenolic compounds (FT) were determined by means of the Folin- Ciocalteu assay and expressed as Equivalents of Gallic Acid (EGA)/g DM. Antioxidant compounds were identified by gas chromatography coupled to mass spectrometry. For CA, there was not significant difference (p>0,05) among extraction methods, but there was significant difference (p<0,05) between solvents (3,39 and 1,28 mg ET/g DM, with methanol and ethanol, respectively). For FT, there was not significant difference (p>0,05) between solvents when they were diluted, but a significant difference (p<0,05) was observed when they were used at 100%. For CA, there was a significant (p<0,05) effect of solvent concentration, both studied solvents at 50% provided the best results (21,34 and 21,82 mg ET/g DM with methanol and ethanol, respectively). The qualitative analysis of the extracts exhibited the presence of squalene and 2,5-bis (1,1-dimethylethyl) phenol as the major compounds with antioxidant capacity.

[Antioxidant capacity of byproducts from amaranth (Amaranthus hypochondriacus) seeds]. / Capacidad antioxidante de subproductos de semillas de amaranto (Amaranthus hypochondriacus).

The antioxidant capacity (CA) of byproducts from amaranth (Amaranthus hypochondriacus) seeds from two harvest parcels as a function of three extraction methods and two solvents was evaluated. On a first stage the effect of extraction method (homogenization, low frequency ultrasound, or the combination homogenization-ultrasound) and extraction solvent (methanol or ethanol, 100%) were evaluated; on a second stage, the effect of extraction solvent concentration (100%, 70%, or 50%) was evaluated. CA was determined by DPPH• inhibition, which was expressed as mg Equivalents of Trolox (ET)/g dry matter (DM). Total Phenolic compounds (FT) were determined by means of the FolinCiocalteu assay and expressed as Equivalents of Gallic Acid (EGA)/g DM. Antioxidant compounds were identified by gas chromatography coupled to mass spectrometry. For CA, there was not significant difference (p>0,05) among extraction methods, but there was significant difference (p<0,05) between solvents (3,39 and 1,28 mg ET/g DM, with methanol and ethanol, respectively). For FT, there was not significant difference (p>0,05) between solvents when they were diluted, but a significant difference (p<0,05) was observed when they were used at 100%. For CA, there was a significant (p<0,05) effect of solvent concentration, both studied solvents at 50% provided the best results (21,34 and 21,82 mg ET/g DM with methanol and ethanol, respectively). The qualitative analysis of the extracts exhibited the presence of squalene and 2,5-bis (1,1-dimethylethyl) phenol as the major compounds with antioxidant capacity.

Antifungal activity by vapor contact of essential oils added to amaranth, chitosan, or starch edible films.

Antimicrobial agents can be incorporated into edible films to provide microbiological stability, since films can be used as carriers of a variety of additives to extend product shelf life and reduce the risk of microbial growth on food surfaces. Addition of antimicrobial agents to edible films offers advantages such as the use of small antimicrobial concentrations and low diffusion rates. The aim of this study was to evaluate inhibition by vapor contact of Aspergillus niger and Penicillium digitatum by selected concentrations of Mexican oregano (Lippia berlandieri Schauer), cinnamon (Cinnamomum verum) or lemongrass (Cymbopogon citratus) essential oils (EOs) added to amaranth, chitosan, or starch edible films. Essential oils were characterized by gas chromatography-mass spectrometry (GC/MS) analysis. Amaranth, chitosan and starch edible films were formulated with essential oil concentrations of 0.00, 0.25, 0.50, 0.75, 1.00, 2.00, or 4.00%. Antifungal activity was evaluated by determining the mold radial growth on agar media inoculated with A. niger and P. digitatum after exposure to vapors arising from essential oils added to amaranth, chitosan or starch films using the inverted lid technique. The modified Gompertz model adequately described mold growth curves (mean coefficient of determination 0.991 ± 0.05). Chitosan films exhibited better antifungal effectiveness (inhibition of A. niger with 0.25% of Mexican oregano and cinnamon EO; inhibition of P. digitatum with 0.50% EOs) than amaranth films (2.00 and 4.00% of cinnamon and Mexican oregano EO were needed to inhibit the studied molds, respectively). For chitosan and amaranth films a significant increase (p<0.05) of lag phase was observed among film concentrations while a significant decrease (p<0.05) of maximum specific growth was determined. Chitosan edible films incorporating Mexican oregano or cinnamon essential oil could improve the quality of foods by the action of the volatile compounds on surface growth of molds.