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8861
Lintnerization of banana starch isolated from underutilized variety: morphological, thermal, functional properties, and digestibility
Pubblicazione 2014Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: The effect of lintnerization on the banana starch of the Roatán cultivar from acid hydrolysis at 3, 5, and 7 days on the starch digestibility and morphological and thermal features was evaluated. Acid treatment produced an increase in the rapidly digestible starch (RDS) (20.2%) and slowly digestible starch (29.7%), but a decrease in the resistant starch (36.3%) content, as compared with its native counterpart. However, over the longest acid-treatment time, a decrease in the RDS over 5 days was observed. The lintnerized banana starch can be used in food products without additional cooking. The temperature (77–80°C) and enthalpy (11.6–14.1 J/g) of gelatinization increased significantly when the acid-treatment time increased, indicating an arrangement of the crystalline lamella by the double helices of the amylopectin chains. The acid treatment increased the retrogradation rate of the lintnerized banana starch gels. The lintnerization of banana starch for different lengths of time modified its morphology, starch digestibility, and thermal features, indicating changes in the crystalline lamella due to the arrangement of the double helices of amylopectin.Acceso al recurso -
8862
Efectos de la irradiación y el nitrato sobre la fotosíntesis en el pasto marino Cymodocea nodosa
Pubblicato in Ciencias Marinas (2023)Fuente: Ciencias MarinasTipo de material: Artículo científicoDescripción: The effects of temperature, irradiance, and other environmental variables on photosynthesis in seagrasses are well understood. However, little information is available regarding the effects of the nitrate concentration in seawater on the photosynthetic characteristics of marine vegetation. Thus, the aim of this study was to determine the effect of the nitrate concentration in seawater on the effective quantum yield of the seagrass Cymodocea nodosa. Cymodocea nodosa shoots were incubated under different irradiance levels and with different nitrate concentrations. In contrast, a decrease in transmittance and an exponential increase in the absorptance of the shoots were observed as a function of increasing nitrate levels. Furthermore, the effective quantum yield of photosystem II (ΦPSII) in C. nodosa shoots increased exponentially as the nitrate concentration in the media increased. The ΦPSII values in the shoots decreased as irradiance increased and reached minimum values at solar noon or 2 h afterward. However, the decrease of ΦPSII values was 4-fold greater in shoots incubated under full solar radiation (100% natural incident irradiance, Eo) compared to those of shoots incubated with 20% Eo. The ΦPSII values decreased to almost zero in shoots pre-incubated with no nitrate (0 μM NO3–), whereas ΦPSII values in shoots pre incubated with 25 and 100 μM NO3– decreased by approximately 25% of their initial values. Collectively, these results indicate that nitrogen levels in seawater regulate the effective quantum yield values of C. nodosa, which suggests that the photosynthetic characteristics of this seagrass might be regulated by fluctuating nitrate levels in the water column such as those that are observed in upwelling regions. Los efectos de la temperatura, la irradiancia y otras variables ambientales sobre la fotosíntesis en los pastos marinos son bien conocidos. Sin embargo, existe poca información sobre los efectos del nitrato en el agua marina sobre las características fotosintéticas de los macrófitos marinos. En este estudio, se planteó determinar el efecto de la concentración de nitrato en el agua marina sobre el rendimiento cuántico efectivo del pasto marino Cymodocea nodosa. Los haces de C. nodosa se incubaron con diferentes concentraciones de nitrato y bajo diferentes niveles de irradiancia. En contraste, hubo una disminución de la transmitancia y un aumento exponencial de la absortancia de los haces en función del aumento de los niveles de nitrato. Además, el rendimiento cuántico efectivo del fotosistema II (ΦFSII) en los haces de C. nodosa aumentó exponencialmente al aumentar la concentración de nitrato en el medio. Los valores de ΦFSII en los haces disminuyeron a medida que aumentaba la irradiancia y alcanzaron valores mínimos al mediodía solar o 2 h después. Esta disminución en los valores de ΦFSII, sin embargo, fue 4 veces mayor en los haces incubados bajo radiación solar completa (100% de Eo) en comparación con los incubados con 20% de Eo. Los valores de ΦFSII disminuyeron a casi cero en los haces pre-incubados con 0 μM de NO3–, mientras que los valores de ΦFSII en los haces pre-incubados con 25 y 100 μM de NO3– disminuyeron aproximadamente un 25% de sus valores iniciales. Estos resultados indican que los niveles de nitrógeno en el agua marina regulan los valores del rendimiento cuántico efectivo de C. nodosa, lo que sugiere que las características fotosintéticas de este pasto marino podrían estar reguladas por los niveles fluctuantes de nitrato en la columna de agua como aquellos observados en las regiones de surgencia.Acceso al recurso -
8863
Opto-Metallurgy and the Photonide Class: Architectural Foundations for Zero-Latency Photonic AI Inference
Pubblicazione 2026Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso -
8864
Vaginal microbiota in Pelibuey sheep treated with antimicrobials at the removal of intravaginal sponges impregnated with flurogestone acetate
Pubblicazione 2019Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: The use of intravaginal sponges produces changes in the composition of the normal vaginal microbiota and provokes the presence of a putrid abnormal fluid at sponge withdrawal. The aim of this study was to compare the effectiveness of the application of three different antibiotics (enrofloxacin, oxytetracycline or nitrofurazone) administered at sponge withdrawal on the vaginal microbiota in ewes. Intravaginal sponges impregnated with fluorogestone were inserted in 40 Pelibuey ewes (Day 0), remaining in situ for 14 days. At sponge withdrawal ewes received: 1) enrofloxacin, 2) oxytetracycline, 3) nitrofurazone, or 4) no treatment (control). The vaginal pH and temperature were recorded, and samples from the vaginal fluid were collected at that moment and 56 h later (Day 16). Samples were incubated to determine the number of Colony Forming Units (CFU). The log CFU increased from Day 0 to Day 14 (P < 0.0001) and decreased on Day 16 (P < 0.0001). On Day 16, the number of CFU was greater in control ewes than in the other three groups (P < 0.0001 for all the comparisons), being enroflaxin the more effective one (vs Toxi: P = 0.019 and vs Tnitro: P = 0.039). We concluded that the growth of the vagina microbiota present the day in which ewes come into estrus provoked by the use of intravaginal sponges may be partially controlled by the application of antibiotics at sponge withdrawal. Enrofloxacin was the most effective antibiotic to decrease bacterial vaginal number.Acceso al recurso -
8865
Malanga starch modified by annealing: Partial characterization and application as wall material in the protection of hibiscus extract
Pubblicazione 2025Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: The hibiscus extract was encapsulated in thermally modified malanga starch (annealing) with the objective of enhancing the protective capacity of the bioactive compounds. Annealing malanga starch was conducted in a 1:9 ratio (starch/water) at temperatures of 67 °C and 70 °C for a period of 48 h. The bioactive compounds and antioxidant activity of the hibiscus extracts were quantified. The physicochemical characterization of native malanga starch (NMS) and starches modified by annealing at 67 °C (SA-67) and 70 °C (SA-70) showed amylose increased by 11.86 %, 13.20 %, and 13.06 %, respectively. The peak temperature (Tp) showed values of 77.76 °C for NMS, 82.57 °C for SA-67, and 83.86 °C for SA-70. As the temperature modification increased, the values of humidity, water activity, and gelatinization enthalpy decreased in the starches. The modifications made by NMS annealing showed that the microcapsules obtained favored the total retention of anthocyanins, with values ranging from 37.93 % (NMS encapsulates) to 54.37 % (SA-70 microcapsules). SA-70 encapsulates exhibited better protective capacity for bioactive compounds than SA-67 ones across an 8-week storage period. Scanning electron microscopy revealed that the modification at 70 °C changes the shape of the starch granule, promoting changes on the surface structure of SA-67 and SA-70 encapsulates compared to NMS encapsulates. These physicochemical changes due to modification by annealing could influence NMS ability to retain anthocyanins when used as a wall material and the stability of microencapsulated bioactive compounds during storage.Acceso al recurso -
8866
Synthesis and characterization of the starch/silicone oil composite and elaboration of its films
Pubblicazione 2022Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Synthesis of the starch/silicone oil composite carried out and its structural characterization by FTIR, Raman and 29Si NMR allowed to identify functional groups of the composite. The synthesis conditions were a starch/silicone oil mass ratio of 2.0 and a temperature of 150 oC to obtain a yield of 84.63 %. SEM analysis showed that the starch granules were covered by silicone oil, this caused a decrease in the crystallinity of starch. Composite films have higher thermal stability compared to native starch. Mechanical properties and electrical conductivity of the starch/silicone oil composite film increase with respect to starch-only films. While the crystallinity of both films is similar. The results obtained in this work indicate that starch/silicone oil composites can be an alternative to make films with a potential use for the packaging industry.Acceso al recurso -
8867
Effect of high-energy mechanical milling on the physicochemical and rheological properties of chayotextle (Sechium edule Sw.) starch
Pubblicazione 2023Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: This work evaluates the effect of high-energy mechanical milling time (7 levels, 20–80 min) on amylose content, crystallinity pattern, temperature and gelatinization enthalpy, morphology, and rheological properties of chayotextle (Sechium edule Sw.) starch. After 30 min of milling, granular structure was affected, and amylose values were the highest while crystallinity and gelatinization enthalpy decreased significantly. These changes allowed to obtain gels with viscoelastic properties where the elastic character (Ǵ) prevailed upon the viscous modulus (Ǵ́). Native starch showed Tan δ values of 0.6, increased significantly (0.9) after 30 min of milling due to the surge in linear chains (amylose) and loss of granular structure. Native and modified starches showed high dependence on cutting or shear speed, presenting a non-Newtonian behavior (reofluidizers). These results indicate that mechanical grinding is an alternative to obtain modified starches with applications in the food industry.Acceso al recurso -
8868
Evaluation of the combined effect of osmotic and Refractance Window drying on the drying kinetics, physical, and phytochemical properties of beet
Pubblicazione 2020Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: The effect of osmotic dehydration (OD) with different sucrose concentrations and temperatures was studied in combination with drying by Refractance WindowTM (RW) in beet slices with thicknesses of 1 and 5 mm. The color, texture, total polyphenol content (TPC), total flavonoid content (TFC), and antioxidant capacity (AC) of the beet with OD, RW, and OD-RW combined drying were evaluated. The best results of water loss (WL) and solid gain (SG) with OD were obtained with 65% sucrose solution at 60 °C. OD partially reduced the water content of the slices, decreasing the drying time with RW at 85 °C. However, the retention of qualities such as color, texture, TPC, TFC, and AC in beet was obtained with combined drying by OD-RW at 60 °C under OD conditions of 65% sucrose at 45 °C. These conditions afforded a stable product retaining its physical and chemical properties.Acceso al recurso -
8869
Spray-drying of Escontria chiotilla fruit juice: effect of the process variables on yield and physicochemical properties
Pubblicazione 2024Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Escontria chiotilla (jiotilla) fruit pulp has a high content of sugars, vitamins, antioxidants, and betalains. However, jiotilla fruits exhibit high susceptibility to microbial attack and physicochemical degradation during storage. Spray-drying of jiotilla fruit juice rich in betalains was carried out using maltodextrin as a carrier material. The effects of inlet (140 and 160 °C) and outlet (80 and 90 °C) temperatures and maltodextrin levels (1 and 2 g·g juice solids⁻¹) on process yield and physicochemical properties of jiotilla powders were studied. Maltodextrin concentration significantly affected (p < 0.05) all evaluated responses, except a_w and °Hue values, whereas drying temperatures did not significantly affect any response. An increase in process yield and luminosity, along with a decrease in chroma values and betalain content, was observed as maltodextrin concentration increased. Physicochemically stable powders (a_w < 0.25), with a color tendency toward red (°Hue: 11–13°), intermediate cohesiveness, fair-to-good flowability, high solubility (92.16%), low hygroscopicity (16.28 g H₂O·100 g db⁻¹), and high contents of betacyanins (82.4–127.1 mg BC·100 g db⁻¹) and betaxanthins (174.7–275.3 mg BX·100 g db⁻¹) were obtained. Jiotilla powder could be applied in the development of food products, even outside the jiotilla fruit production season.Acceso al recurso -
8870
In search of cytotoxic selectivity on cancer cells with biogenically synthesized Ag/AgCl nanoparticles
Pubblicazione 2022Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Green synthesis may be a useful approach to achieve selective cytotoxicity of silver nanoparticles on cancer cells and healthy cells. In this study, the concomitant biosynthesis of silver (Ag)/silver chloride (AgCl) nanoparticles from pineapple peel extracts and their behavior on the breast cancer cell line MCF-7 is shown. Bioreactions were monitored at different temperatures. Fourier-transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–vis), thermogravimetric analysis (TGA), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM) techniques were used to characterize nanoparticle development. The breast cancer cell line MCF-7 was used as a test model to study the cytotoxic behavior of Ag/AgCl nanoparticles and, as a counterpart, the nanoparticles were also tested on mononuclear cells. Ag/AgCl nanoparticles with spherical and triangular morphology were obtained. The size of the nanoparticles (10–70 nm) and the size distribution depended on the reaction temperature. A dose close to 20 µg/mL of Ag/AgCl nanoparticles considerably decreased the cell viability of the MCF-7 line. The best cytotoxicity effects on cancer cells were obtained with nanoparticles at 60 and 80 °C where cell viability was reduced up to 80% at a concentration of 50 µg/mL. A significant preference was observed in the cytotoxic effect of Ag/AgCl nanoparticles against cancer cells in comparison to monocytes.Acceso al recurso -
8871
Distribución espaciotemporal de la contaminación bacteriana del agua residual agrícola y doméstica descargada a un canal de drenaje (Sinaloa, México)
Pubblicato in Ciencias Marinas (2013)Fuente: SIBUMAR · Ciencias MarinasTipo de material: LibroDescripción: The agricultural drainage water from the Sinaloa valley (Mexico) is often reused in agriculture and aquaculture before reaching coastal water bodies. Discharged water must be of good quality to maintain the health of ecosystems and prevent damage to the organisms that compose them. This research determined the occurrence of coliforms in a drainage ditch known as La Michoacana (Sinaloa) that receives contaminated water from agricultural and urban sources. A section of 3.6 km was studied during 2013 and samples were obtained monthly from five equidistant sampling sites. Each water sample was analyzed for total coliform (TC) and fecal coliform (FC) content, pH, salinity, temperature, and dissolved oxygen percentage (%DO). The sampling sites with the highest bacterial contamination were associated with direct discharges of domestic wastewater and those with the lowest to the output drain. The performance of this agricultural ditch decreased the concentration of coliforms, with median and average values of 96% and 87% for TC, and 98% and 85% for FC, respectively. The most common bacteria were Escherichia coli (67.7%), Kluyvera cryocrescens (10.2%), and Enterobacter agglomerans (6.3%). Coliform concentration was positively correlated with temperature and negatively with %DO. The ditch improved the microbiological quality of the water, demonstrating remediation activities in the system. Proper management and maintenance of agricultural drainage ditches would favorably impact the health and biodiversity, as well as the intensive aquaculture and agricultural activities of the Sinaloa valley. El agua que conducen los canales de drenaje del valle agrícola sinaloense (México) es reutilizada con frecuencia en la agricultura y acuacultura antes de ser depositada en las aguas costeras. La calidad del agua descargada debe ser adecuada para mantener la salud de los ecosistemas y evitar daño a los organismos que los componen. Esta investigación determinó la presencia de coliformes en el canal de drenaje agrícola conocido como La Michoacana (Sinaloa), que recibe agua contaminada de fuentes agrícolas y urbanas. Se estudió una sección de 3.6 km del canal durante el año 2013 y se recolectaron mensualmente muestras de agua de cinco puntos de muestreo equidistantes. A cada muestra se le analizó el contenido de coliformes totales (CT) y coliformes fecales (CF), pH, salinidad, temperatura y porcentaje de saturación de oxígeno disuelto (%OD). Los puntos de muestreo con mayor contaminación bacteriana estuvieron asociados a las descargas directas de agua residual doméstica, y aquellos con menor contaminación estuvieron asociados a la salida del canal de drenaje. El funcionamiento del canal disminuyó la carga de coliformes, con medianas y valores promedio del 96% y 87% para CT, y 98% y 85% para CF, respectivamente. Las principales bacterias identificadas fueron Escherichia coli (67.7%), Kluyvera cryocrescens (10.2%) y Enterobacter agglomerans (6.3%). La concentración de coliformes presentó una correlación positiva con la temperatura y negativa con el %OD. El canal de drenaje La Michoacana mejora la calidad microbiológica del agua que conduce, lo cual demuestra funciones de remediación en el sistema. El mantenimiento y manejo adecuado de los canales de drenaje agrícola puede impactar favorablemente la salud y biodiversidad, así como las actividades acuícolas y agrícolas intensivas del valle sinaloense.Acceso al recurso -
8872
Dual modification of chayotextle starch: effect on physicochemical, functional, and structural properties
Pubblicazione 2023Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Chemically modified starches are widely used as food additives to improve the appearance and physicochemical and biological properties of foods. The aim of this work is to chemically modify chayotextle (Sechium edule) starch by hydroxypropylation-crosslinking, and evaluate the effects of degree of substitution (DS), swelling power (SP), solubility index (SI), pasting, thermal properties, and morphological and molecular characteristics. Polar-Tex (modified maize starch) is used as control. The modified chayotextle starches (CHSs) exhibit a white color and DS values between 0.34% and 1.19% hydroxypropyl, dependening on propylene oxide concentration-response. In addition, the SP and pasting properties are higher in modified CHS than in native CHS and Polar-Tex. The SI and temperature of gelatinization of modified starches decrease compared to native sample. The morphology of native and modified CHS granules is spherical and oval. Fourier transform infrared and nuclear magnetic resonance studies confirm the structural modifications of CHS by hydroxypropylation-crosslinking. Dual-modified CHS can be potentially used as an additive in the food industry.Acceso al recurso -
8873
Preengorda del Ostión Americano (Crassostrea virginica) en lagunas costeras tropicales en Yucatán, México: modelación de regresión no lineal y relaciones con variables ambientales...
Pubblicato in Ciencias Marinas (2024)Fuente: Ciencias MarinasTipo de material: Artículo científicoDescripción: Nonlinear regression modeling was used to study the nursery production of the oyster Crassostrea virginica in the Celestún (CL) and Rio Lagartos (RL) lagoons in Yucatán, Mexico. Relationships between production parameters and environmental variables were also established. Spat (2.40 ± 0.20 mm) was obtained from a hatchery and reared in Nestier-type trays using an off-bottom system. Oyster cultivation took place from May 2021 to September 2021 and ended after 122–126 days when oysters reached 30.00 mm. There were no significant differences in final height (CL: 30.80 ± 0.42 mm; RL: 31.80 ± 0.65 mm; P = 0.18) and growth rate (CL: 0.23 ± 0.02 mm·d–1; RL: 0.23 ± 0.01 mm·d–1; P = 0.98). Final survival was 71.45% in CL and 99.40% in RL. Nonlinear regression curves were statistically satisfactory for analyzing growth and survival. Except for dissolved oxygen, mean salinity (CL: 15.23 ppt; RL: 35.02 ppt), temperature (CL: 29.64 °C; RL: 31.02 °C), dissolved oxygen (CL: 4.50 mg·L–1; RL: 5.04 mg·L–1), pH (CL: 8.10; RL: 8.34), chlorophyll a (Chl a) (CL: 3.23 mg·m–3; RL: 6.85 mg·m–3), and total dissolved solids (CL: 16,101 mg·L–1; RL: 34,838 mg·L–1) were significantly higher in RL (P < 0.05). Except for Chl a, the environmental variables were more stable in RL than in CL (P < 0.05). In RL, the growth rate was positively related to salinity and pH. In CL, the growth rate slowed when salinity decreased, and the mortality rate diminished when salinity, dissolved oxygen, and total dissolved solids increased and pH decreased. Salinity was mainly responsible for the observed differences in production between lagoons. Even when temperature and salinity were high in RL, acceptable growth rate and survival were observed, possibly due to stable rearing conditions. Se usaron modelos de regresión no lineal para analizar la producción en preengorda de Crassostrea virginica en 2 lagunas costeras de Yucatán, México: Celestún (CL) y Río Lagartos (RL). Adicionalmente, se establecieron relaciones entre la producción y las variables ambientales. Las semillas (2.40 ± 0.2 mm) se cultivaron en suspensión de mayo a septiembre 2021 en canastas Nestier durante 122-126 días, hasta que los ostiones alcanzaron 30.00 mm. No hubo diferencias significativas en la altura final (CL: 30.80 ± 0.42 mm; RL: 31.80 ± 0.65 mm; P = 0.18) ni en la tasa de crecimiento (CL: 0.23 ± 0.02 mm·d–1; RL: 0.23 ± 0.01 mm·d–1; P = 0.98) entre sitios. La supervivencia fue 71.40% en CL y 99.40% en RL. Las curvas de regresión no lineal resultaron estadísticamente satisfactorias para analizar el crecimiento y la supervivencia. La salinidad (CL: 15.23 ppt; RL: 35.02 ppt), la temperatura (CL: 29.64 °C; RL: 31.02 °C), el oxígeno disuelto (CL: 4.50 mg·L–1; RL: 5.04 mg·L–1), el pH (CL: 8.10; RL: 8.34), la clorofila a (Cl a) (CL: 3.23 mg·m–3; RL: 6.85 mg·m–3) y los sólidos disueltos totales (CL: 16,101 mg·L–1; RL: 34,838 mg·L–1) fueron superiores en RL (P < 0.05). Exceptuando la Cl a, las variables fueron más estables en RL (P < 0.05). En RL, el crecimiento se relacionó positivamente con la salinidad y el pH. En CL, el crecimiento disminuyó al bajar la salinidad, y la mortalidad disminuyó cuando la salinidad, el oxígeno disuelto y el total de sólidos disueltos se incrementaron y el pH disminuyó. La salinidad fue determinante para la diferencia en producción entre las lagunas. En RL, el crecimiento y la supervivencia fueron aceptables aun con temperaturas y salinidades relativamente elevadas, posiblemente debido a las condiciones estables de cultivo.Acceso al recurso -
8874
Effects of formulation and process conditions on chemical composition, color parameters, and acceptability of extruded insect-rich snack
Pubblicazione 2021Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: A ready-to-eat, protein-rich snack was developed using a blend of nixtamalized maize (Zea mays L.) flour and grasshopper (Sphenarium purpurascens Ch.) meal, and an evaluation of the effects of the formulation and extrusion processing on the chemical composition, color parameters, and acceptability of the extrudates was conducted. The increase in extrusion temperature (120–180ºC) decreased the moisture (8.14–5.91 g/100 g) and lipid content (2.20–1.95 g/100 g) and increased aroma (3.82–4.24), texture (1.61–4.82), flavor (2.67–4.52), and overall acceptability (2.88–4.67). The increase in the grasshopper meal proportion (0–40 g/100 g) decreased the carbohydrate content (89.45–65.39 g/100 g), and whiteness index (68.51–47.14) and increased the protein (5.33–22.51 g/100 g) and ash contents (1.67–7.88 g/100 g), color difference (30.98–52.30), and browning index (24.28–39.77). The acceptability of the snack was oriented toward extrudates that had a color with a high L* (Corr = 0.74), with yellow tones b* (Corr = 0.73), and a whiteness index (Corr = 0.72). Therefore, the best products were those obtained at 167.8°C, proportion of grasshopper meal = 8.11 g/100 g, and a feed moisture content of 18.81 and 21.19 g/100 g, respectively, with a protein content of 13.27 and 13.66 g/100 g.Acceso al recurso -
8875
Resistant starch from plantain (Macho Musa paradisiaca L.) and banana (Roatan Musa sapientum L.) varieties crosslinked with epichlorohydrin
Pubblicazione 2024Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Resistant starch from plantain (Macho Musa paradisiaca L.) and banana (Roatan Musa sapientum L.) varieties was chemically modified by crosslinking using epichlorohydrin (EPI). These modified starches were subjected to in vitro digestibility studies using the Englyst method to determine the content of rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS). The thermal stability of these crosslinked starches was evaluated by gelatinization and retrogradation analyses, and their enthalpies were determined using differential scanning calorimetry (DSC). Additionally, their functional properties were evaluated. Chemical modification with EPI significantly increased the RS content in both starch varieties compared to that in native starch. The enthalpy and gelatinization temperature decreased in the EPI-modified starches of both varieties, indicating lower thermal stability during the gelatinization process compared to that of native starch. In general, both varieties of crosslinked plantain starch had lower viscosity (0.43 Pa*s) than did native starch (0.58 Pa*s). The results indicates that this starch crosslinked with EPI constitutes an alternative for use in food for people with health problems such as high cholesterol levels or postprandial insulin concentrations.Acceso al recurso -
8876
Effect of cross-linking on the physicochemical, functional and digestibility properties of starch from Macho (Musa paradisiaca L.) and Roatan (Musa sapientum L.) banana varieties
Pubblicazione 2015Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Starches from the Macho (Musa paradisiaca L.) and Roatan (Musa sapientum L.) banana varieties were chemically modified by sodium trimetaphosphate (STMP) cross-linking. Cross-linking affected the pasting properties of the modified starch, with more pronounced changes observed in the Macho variety than in the Roatan starch. In turn, this result indicated that the former starch source is more susceptible to STMP cross-linking. The swelling and solubility profiles exhibited an important decrease with cross-linking, which was caused by increased ordering of the internal granule structure induced by cross-linking modifications. The gelatinization temperature and enthalpy increased due to cross-linking, indicating an improvement in the starch granule stability. Englyst's in vitro digestibility studies of the modified starch were performed to estimate the content of rapidly digestible (RDS), slowly digestible (SDS) and resistant (RS) starch fractions. It was shown that STMP cross-linking increased the RS content of the two banana varieties. However, the SDS content increased only for the Macho variety. In general, the viscosity was lower for the modified starches than for their native counterparts. The results of the current work indicate that the chemical modification process via STMP cross-linking offers an interesting alternative for obtaining RS from banana starches.Acceso al recurso -
8877
SEC-ZEFFO COSMOLOGY: UNIFIED RESOLUTION OF DARK MATTER, DARK ENERGY, H₀ TENSION, AND BLACK HOLE INFORMATION PARADOX VIA GRAVITATIONAL POLARISATION*
Pubblicazione 2026Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso -
8878
Producción masiva de Tetraselmis suecica (Kylin) Butch. (Prasinophyceae), bajo diferentes concentraciones de nutrientes y ediciones de dióxido de carbono
Pubblicato in Ciencias Marinas (1991)Fuente: Ciencias MarinasTipo de material: Artículo científicoDescripción: A series of four experiments with Tetraselmis suecica was carried out under laboratory conditions in order to learn the production yield in volumes of 1,000 litres, with salinity of 28‰, with absence and addition of buffer and carbon dioxide, air flow of 25 I/min and average time of addition of carbon dioxide of two and a half minutes, at a pressure of 50 kg/cm2 to keep the pH equal to or below 7.5. A maximum density of 508,000 cells/ml was obtained with a ratio of 150/10 g/l of NaN03/NaH2P04, with an average constant of growth of 0.35 and 0.50 doublings per day. With a quarter and with half of the nutrients without buffer, a higher constant of growth was recorded, although it did not differ significantly at 95% confidence in relation to the control experiment. Productivity per unit of culture volume of T. suecica showed that on using low concentrations of nutrients plus carbon dioxide, good population yields relative to the control are obtained. Productivity was not affected by temperature since it was kept constant at 19 + 1ºC, but it decreases when the supplement of carbon dioxide is insufficient to keep the pH between 7.2-7.5. En condiciones de laboratorio se efectuó una serie de cuatro experimentos con Tetraselmis suecica, para conocer el rendimiento de producción en volúmenes de 1,000 litros, con salinidad de 28‰, con ausencia y adición de amortiguador y dióxido de carbono, flujo de aire de 25 l/min y tiempo promedio de adición de dióxido de carbono de dos minutos y medio, a 50 kg/cm2 de presión para mantener el pH igual o menor de 7.5. La máxima densidad de 508,000 cel/ml se obtuvo con la relación de 150/10 g/l de NaNO3/NaH2P04, con una constante de crecimiento promedio de 0.35 y 0.50 duplicaciones por día. Con un cuarto y la mitad de nutrientes sin amortiguador, se registró una constante de crecimiento promedio mayor, aunque no difirió significativamente al 95% de confianza con respecto al experimento control. La productividad por unidad de volumen de cultivo de T. suecica mostró que al utilizar bajas concentraciones de nutrientes más dióxido de carbono, se obtienen buenos rendimientos poblacionales respecto al control. La productividad no fue afectada por temperatura ya que se mantuvo constante 19 + 1ºC, pero decrece si el suplemento de dióxido de carbono es insuficiente para mantener el pH entre 7.2-7.5.Acceso al recurso -
8879
Efectos de la pesquería del pulpo sobre la población de la cacerolita de mar en la Reserva de la Biosfera Ría Lagartos, México
Pubblicato in Ciencias Marinas (2020)Fuente: Ciencias MarinasTipo de material: Artículo científicoDescripción: The American horseshoe crab, Limulus polyphemus, has been reported to be illegally caught for use as Octopus spp. bait in some localities of the Yucatán Peninsula, Mexico. To learn if the octopus fishery could be negatively influencing the limulus populations in the area, L. polyphemus individuals were sampled twice a year, before and after the annual octopus fishing season, over 4 consecutive years (2015–2018) in Río Lagartos and San Felipe, both in the Ría Lagartos Biosphere Reserve (RLBR), Yucatán. Quadrants were drawn perpendicular to the mangrove edge, physicochemical parameters in the water (depth, temperature, dissolved oxygen, pH, salinity, and electrical conductivity) were determined, and granulometry of marine sediments was measured (Folk technique). The number of live specimens, number of females, and average length were recorded. No significant differences were found for the physicochemical properties of water or the recorded sedimentology (P > 0.05). Samplings revealed a low number of organisms per site: 22 in Río Lagartos and 24 in San Felipe, both from data before the start of the 2017 octopus fishing season. In the samplings after the start of the 2018 octopus fishing season, only 2 organisms were observed in Río Lagartos and none in San Felipe. The results showed a significant decrease in the number of live L. polyphemus specimens after the beginning of the octopus fishing season and a decrease in the average length of organisms, suggesting a negative effect of mollusk fishing activities on the horseshoe crab populations. More studies are required that integrate other physicochemical, biological, and socioeconomic factors to elucidate the potential threat of this fishery on L. polyphemus populations in the RLBR. Se ha documentado que la cacerolita de mar Limulus polyphemus se captura de forma ilegal para uso como carnada de Octopus spp. en algunas localidades de la península de Yucatán, México. Para conocer si la pesquería de pulpo pudiese tener una influencia negativa en las poblaciones de este límulo, se muestrearon organismos de L. polyphemus 2 veces al año, antes y después del comienzo de la temporada anual de pulpo, durante 4 años consecutivos (2015–2018) en Río Lagartos y San Felipe, situados en la Reserva de la Biosfera Ría Lagartos (RBRL), Yucatán. Se trazaron cuadrantes perpendiculares a la vera del manglar y se midieron los parámetros fisicoquímicos del agua (profundidad, temperatura, oxígeno disuelto, pH, salinidad y conductividad eléctrica), así como la granulometría del sedimento marino (mediante el tamizado de Folk). Se registró el número de individuos vivos, el número de hembras y la longitud promedio. No se encontraron diferencias significativas en los parámetros fisicoquímicos del agua ni en la sedimentología registrada (P > 0.05). Los muestreos evidenciaron pocos organismos por sitio estudiado: 22 en Río Lagartos y 24 en San Felipe, ambos resultados antes de iniciada la temporada de pulpo de 2017. En los muestreos posteriores al inicio de la temporada de pulpo de 2018, solo se observaron 2 organismos en Río Lagartos y ninguno en San Felipe. Los resultados evidenciaron una disminución significativa en el número de ejemplares vivos de L. polyphemus después de iniciada la temporada de pulpo, así como también una disminución en la longitud promedio de los organismos, lo que sugiere un efecto negativo en las poblaciones de la cacerolita de mar derivado de las actividades propias de la pesca del molusco. Se requieren más estudios que integren otros factores fisicoquímicos, biológicos y socioeconómicos para dilucidar la potencial amenaza de esta pesquería sobre las poblaciones de este límulo en la RBRL.Acceso al recurso -
8880
Effect of oxidation and crosslinking on functional, rheological and thermal properties of oat and apple starches
Pubblicazione 2024Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Oat (Oa) and apple (Ap) starches were isolated and chemically modified by oxidation with 10% NaOCl to obtain oxidized starches (OOa and OAp), followed by cross-linking with a mixture of 5.6 g of sodium tripolyphosphate and 11 g of sodium trimetaphosphate to obtain doubly modified starches (OCOa and OCAp). In the native and modified starches, the functional properties (swelling power and solubility, and freeze-thaw stability) and thermal and rheological properties (steady-state flow curves and paste formation profile) were evaluated. The swelling power of native and double modified starches varied from 57 to 86 g/g and the solubility from 0.8 to 6.0 g/100 g, these variables increased as the study temperature increased; the increment in these properties was greater in Oa compared to Ap. Oxidation followed by crosslinking increased the freeze-thaw stability in Oa and Ap starches at 30, 60, 75, and 90 °C. It also increased the Tg of OCAp and OCOa ≈ 9% compared to the native samples, respectively; while an inverse pattern was observed in apparent viscosity were this value decreased ≈ 0.8 Pa × s for Oa and ≈ 0.5 Pa × s for Ap compared to the double modified samples. All samples presented a thinning cut-type behavior (pseudoplastic), indicating structural differences. Cross-linking in oxidized starches produced a reinforcing matrix that was determined in the paste formation profile. Dual modification (oxidation-cross-linking) could be an alternative for using starches from underused botanical sources, such as apples and oats, with different functional properties and feasible applications in food systems.Acceso al recurso