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16601
Efecto de tres métodos de cocción sobre el contenido nutricional de la mojarra Tilapia (Oreochromis sp.)
Published 2011Fuente: Universidad del PapaloapanTipo de material: TesisDescripción: En este proyecto se estudió el efecto de tres métodos de cocción sobre la calidad nutricional de la tilapia (Oreochromis sp.) y sobre dos parámetros fisicoquímicos (actividad de agua aw y pH). Así, se utilizó un diseño experimental completamente al azar mediante dos réplicas con tres repeticiones, donde los tratamientos fueron: horno a 60 y 80 °C, vapor a 60 y 80 °C y microondas a 140 y 1400 Watts y las variables de respuesta fueron: porcentaje de proteína, lípidos, cenizas y humedad, Aw y pH. Para el análisis estadístico de los datos obtenidos se efectuó análisis de varianza (ANOVA) y comparativo de medias con la prueba de Tukey (P<0.05). Con el fin de evaluar de manera cualitativa el efecto sobre las proteínas totales también se efectuó análisis electroforético. Los resultados de la composición proximal de la muestra fresca de la tilapia fueron: proteína 22.16 ± 0.04 %, lípidos 1.3 ± 0.01 %, cenizas 1.14 ± 0.008 % y humedad 78.11 ± 0.18 %, similares a lo reportado en la literatura. Los valores de los parámetros fisicoquímicos de la muestra fresca fueron: actividad de agua de 0.98 ± 0.008 y pH de 6.64 ± 0.008. La composición proximal y los parámetros fisicoquímicos de la tilapia fueron afectados significativamente (P < 0.05) por los tres métodos de cocción. Los mejores tratamientos para la conservación de proteínas fueron: microondas a 140 y 1400 Watts y el método que mostró mayor pérdida de proteína fue el horno a 80 °C. Por otra parte, se observó una mayor pérdida de lípidos en los tratamientos de vapor a 60 °C y microondas a 140 Watts en comparación con los métodos de cocción horno a 60 y 80 °C. El análisis electroforético demostró cualitativamente que, después de la aplicación, los métodos de cocción a microondas (140 y 1400 Watts) y vapor (60 °C) presentaron más bandas de proteína en comparación con los métodos de horno (60 y 80 °C) y de vapor (80 °C). En el método de cocción en horno eléctrico con las dos temperaturas empleadas (60 y 80 °C) se observó menor cantidad de bandas proteicas. Los resultados de este estudio sugieren la aplicación del método de cocción por microondas y por vapor para mayor aprovechamiento de las proteínas de la tilapia y, para los lípidos, el horno convectivo.Acceso al recurso -
16602
Lintnerization of banana starch isolated from underutilized variety: morphological, thermal, functional properties, and digestibility
Published 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 -
16603
A note on upper ocean temperature and salinity at the entrance to the gulf of californiain august 1992
Published in Ciencias Marinas (1997)Fuente: Ciencias MarinasTipo de material: Artículo científicoDescripción: Fernández-Barajas et al. (1994) reportan los resultados de mediciones hidrográficas realizadas en la entrada del Golfo de California en agosto de 1992. Durante ese crucero, el CTD se encontraba calibrado inadecuadamente, teniendo como resultado mediciones anómalas de altas temperaturas y bajas salinidades. Fernández-Barajas et al. (1994) incorrectamente atribuyeron estas condiciones anómalas al fenómeno El Niño de 1991- 1993 y a la tormenta tropical Lester. Fernández-Barajas et al. (1994) report results of hydrographic measurements at the entrance to the Gulf of California in August 1992. During this cruise, the CTD was improperly calibrated, and this resulted in anomalously high (low) near-surface temperatures (salinities) being reported. Fernández-Barajas et al. (1994) incorrectly attribute these anomalous surface conditions to the 1991-1993 El Niño and tropical storm Lester.Acceso al recurso -
16604
Spatial variation of the abundance of the soft-bottom fauna on the continental shelf off cjalisco and colima, mexico (spring 1995)
Published in Ciencias Marinas (1997)Fuente: Ciencias MarinasTipo de material: Artículo científicoDescripción: La distribución espacial de la abundancia de la fauna de fondos blandos en la plataforma continental de Jalisco y Colima (costa del Pacífico de México) fue investigada mediante un censo realizado con redes de arrastre para la pesca de camarón. Se tomaron muestras en siete localidades, a profundidades medias de 20, 40, 60 y 80 m en mayo y junio de 1995. Los índices de abundancia fueron expresados como número de individuos y peso total por unidad de área barrida, expresada en hectáreas. Los valores obtenidos mostraron una varianza muy alta, con intervalos de 30 a 1,952 ind/ha y 0.6 a 110.3 kg/ha para los peces y de 121 a 6,536 ind/ha y 1.0 a 64.5 kg/ha para los invertebrados. Se encontraron diferencias en los índices de abundancia medios entre localidades, pero no se pudo determinar una causa para estas diferencias. Los índices de abundancia medios variaron con la profundidad, probablemente debido a la variación de la temperatura del agua adyacente al fondo. En la profundidad de 60 m se encontró un gran número de peces pequeños, principalmente de las familias Batrachoididae, Scorpaenidae y el orden Pleuronectiformes. A 20 y 40 m se encontró un número de individuos menor pero valores más altos de peso por unidad de área, debido a la dominancia en estos niveles de especies con un peso individual medio mayor, como las de la familia Diodontidae y el orden Rajiformes. Los invertebrados presentaron tallas más uniformes en todo el gradiente de profundidad y fueron más abundantes a 60 m. Las especies de la familia Portunidae fueron dominantes. Spatial distribution of the abundance of the soft-bottom fauna on the continental shelf off Jalisco and Colima (Pacific coast of Mexico) was investigated through a survey with shrimp trawl nets. Samples were taken at seven sites with mean depths of 20, 40, 60 and 80 m during May and June 1995. Abundance indexes are given as number of individuals and total weight per unit of area swept in hectares. The values obtained showed a very high variance, with ranges from 30 to 1.952 ind/ha and 0.6 to 110.3 kg/ha for the fishes. and from 121 to 6,536 ind/ha and 1.0 to 64.5 kg/ha for the invertebrates. Differences in mean abundance indexes between sites were found, but the cause for these was not determined. Mean abundance indexes changed with depth, probably due to changes in the temperature of the water near the bottom. At the depth of 60 m, a high number of small fishes, mainly of the families Batrachoididae, Scorpaenidae and the order Pleuronectiformes, were found. At 20 and 40 m. a lesser mean number of individuals but a higher total weight per unit area were found as a consequence of the predominance in these levels of species with a higher mean individual weight, such as those of the family Diodontidae and the order Rajiformes. Invertebrates had a more uniform size throughout the depth gradient and were more abundant at the depth of 60 m. The species of the family Portunidae were dominant.Acceso al recurso -
16605
Opto-Metallurgy and the Photonide Class: Architectural Foundations for Zero-Latency Photonic AI Inference
Published 2026Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso -
16606
Vaginal microbiota in Pelibuey sheep treated with antimicrobials at the removal of intravaginal sponges impregnated with flurogestone acetate
Published 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 -
16607
Malanga starch modified by annealing: Partial characterization and application as wall material in the protection of hibiscus extract
Published 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 -
16608
Synthesis and characterization of the starch/silicone oil composite and elaboration of its films
Published 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 -
16609
Effect of high-energy mechanical milling on the physicochemical and rheological properties of chayotextle (Sechium edule Sw.) starch
Published 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 -
16610
Evaluation of the combined effect of osmotic and Refractance Window drying on the drying kinetics, physical, and phytochemical properties of beet
Published 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 -
16611
Spray-drying of Escontria chiotilla fruit juice: effect of the process variables on yield and physicochemical properties
Published 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 -
16612
In search of cytotoxic selectivity on cancer cells with biogenically synthesized Ag/AgCl nanoparticles
Published 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 -
16613
Dual modification of chayotextle starch: effect on physicochemical, functional, and structural properties
Published 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 -
16614
Biología reproductiva del berberecho Cerastoderma glaucum (Mollusca: Bivalvia) de la costa norte de Sfax (Golfo de Gabes, Túnez)
Published in Ciencias Marinas (2009)Fuente: Ciencias MarinasTipo de material: Artículo científicoDescripción: The reproductive cycle of the cockle Cerastoderma glaucum from the Gulf of Gabes (southern Tunisia) was studied during a one-year period (January to December 2007). The overall samples presented a balanced sex ratio, with males dominating among smaller individuals and females predominating in larger size classes. Males were found to mature between 12 and 20 mm shell length (SL), whereas females matured between 14 and 21 mm SL. The size at which 50% of the population reached maturity was 15.14 and 16.78 mm SL for males and females, respectively. The seasonal changes assessed through macro- and microscopic properties in the gonads of both sexes indicated a clearly defined annual reproductive cycle. Reproductive activity of C. glaucum was greatest from spring to late autumn, with two reproductive peaks (May and November). Gametogenic activity in both sexes was apparently triggered by the rising seawater temperature during spring and summer. These results support previous findings of latitudinal changes in the reproductive behaviour of C. glaucum. Due to the extensive period of gonadal activity, C. glaucum exhibited a short resting phase that occurred simultaneously in both sexes throughout January and February. Upon inspection for parasitic infections, 15% of C. glaucum were found infected by digenean trematode species. The number of specimens showing digenean infestations differed with size class, with a tendency to increase significantly with cockle size. Se estudió el ciclo reproductivo del berberecho Cerastoderma glaucum del Golfo de Gabes (sur de Túnez) durante un periodo de un año (enero a diciembre de 2007). Las muestras en general presentaron una razón de sexos balanceada, con los machos predominando entre los individuos de menor talla y las hembras entre los de mayor talla. Los machos maduraron al alcanzar entre 12 y 20 mm de longitud de concha (LC) y las hembras entre 14 y 21 mm LC. La talla a la cual 50% de la población alcanzó la madurez fue de 15.14 y 16.78 mm LC para machos y hembras, respectivamente. Los cambios estacionales evaluados a través de propiedades macro y microscópicas de las gónadas de ambos sexos indicaron un ciclo reproductivo anual bien definido. La actividad reproductiva de C. glaucum fue mayor entre primavera y finales de otoño, mostrando dos picos (mayo y noviembre). La actividad gametogénica en ambos sexos aparentemente fue provocada por el incremento en la temperatura del agua de mar durante la primavera y el verano. Estos resultados apoyan lo informado anteriormente en cuanto a cambios latitudinales en el patrón reproductivo de C. glaucum. Debido al extenso periodo de actividad gonádica, C. glaucum presentó una fase corta de descanso, simultánea en ambos sexos durante enero y febrero. Se examinaron los especímenes para detectar infestaciones parasíticas, encontrándose que 15% de aquellos estaban infectados por especies de tremátodos digéneos. El número de especímenes que mostraron tales infestaciones difirió según la clase de talla, con una tendencia a incrementar significativamente con la talla.Acceso al recurso -
16615
Propiedades bioquímicas y bacteriológicas de la lisozima de la almeja Tivela stultorum
Published in Ciencias Marinas (2000)Fuente: Ciencias MarinasTipo de material: Artículo científicoDescripción: A lysozyme-like enzyme from the crystalline style of the clam Tivela stultorum was purified by chromatography of cationic exchange in carboxymethyl cellulose. The product had a specific activity of 25,407 units per milligram of protein, which represents a purification of 100 times. The specific activity observed with this enzyme was almost six times greater than the activity observed in the hen egg-white lysozyme under the same conditions. Using the isoelectric focusing technique, a component was observed that indicates an isoelectric point of 7.7 (IEF-PAGE, Phast Gel). A one-dimensional electrophoresis (SDS-PAGE) revealed an apparent molecular weight of 17,000 daltons. The enzyme was optimally active at pH 5.6–5.8, in 0.1 M phosphate-citrate buffer, with maximum activity at a temperature of 40ºC, and an ionic strength of 0.1043. At 4ºC, the lysozyme presented 26.7% of remnant activity, and was highly stable at elevated temperatures (90ºC) and extreme pHs, from 2.8 to 11.8, with activities above 75%. This enzyme proved to have antimicrobial properties with or without EDTA in the lysis of three bacteria (Streptococcus alfa, Micrococcus lisodeikticus and Escherichia coli), whereas hen egg lysozyme showed lysis in the presence of EDTA on S. alfa and E. coli. The results were also compared against the lysozyme of the scallop Chlamys islandica. Una enzima tipo lisozima proveniente del estilete cristalino de la almeja Tivela stultorum fue purificada por cromatografía de intercambio catiónico en carboximetil celulosa. El producto tuvo una actividad específica de 25,407 unidades por miligramo de proteína, representando una purificación de 100 veces. La actividad específica observada por esta enzima fue casi seis veces mayor que la actividad observada en la lisozima de clara de huevo de gallina bajo las mismas condiciones. Mediante la técnica de isoelectroenfoque se observó un componente indicando un punto isoeléctrico de 7.7 (IEF-PAGE, Phast Gel). Por medio de electroforesis de una dimensión (SDS-PAGE), se sugiere un peso molecular aparente de 17,000 daltons. La enzima fue óptimamente activa a pH de 5.6 a 5.8, en amortiguador citrato fosfato 0.1 M, con actividad máxima a una temperatura de 40ºC, y con una fuerza iónica de 0.1043. A 4ºC la lisozima presentó 26.7% de actividad remanente, además de mostrar ser altamente estable a temperatures elevadas (90ºC) y pHs extremos con actividades por arriba del 75%, en un rango de pHs de 2.8 a 11.8. Dicha enzima mostró tener propiedades antimicrobianas en presencia y ausencia de EDTA sobre la lisis de tres bacterias (Streptococcus alfa, Micrococcus lisodeikticus y Escherichia coli), mientras que la lisozima de huevo de gallina sólo mostró lisis en presencia de EDTA sobre S. alfa y E. coli. Los resultados también fueron comparados contra una lisozima de la almeja ártica Chlamys islandica.Acceso al recurso -
16616
Variación estacional de biomasa de Chondracanthus canaliculatus (Rhodophyta, Gigartinales) asociada con factores ambientales, a través de un análisis de componentes principales
Published in Ciencias Marinas (1996)Fuente: Ciencias MarinasTipo de material: Artículo científicoDescripción: Associations between biomass (dry weight) of Chondracanthus canaliculatus (Harvey) Guiry and atmospheric and seawater temperature, wave energy and hours of tidal emersion were determined using a principal components analysis. Bimonthly samples of C. canaliculatus biomass were collected from November 1988 to November 1989, Chondracanthus canaliculatus biomass had a marked seasonal cycle, with maximum values of biomass in summer (670 g m–2) and minimum in winter (126 g m–2). The principal components analysis showed that high biomass (grater than 543 g m–2) was associated with high atmospheric temperatures (greater than 21.4ºC) and low wave energy (less than 95.7 cm). Low biomass (less than 323 g m–2) was associated with low atmospheric temperatures (less than 17.2ºC) and tidal emersion between 81.5 and 109 h. Medium biomass values (323-543 g m–2) were associated with high water temperatures (grater than 16ºC). Se determinaron las asociaciones entre la biomasa (peso seco) de Chondracanthus canaliculatus (Harvey) Guiry y la temperatura atmosférica y del agua, energía del oleaje y horas de exposición debidas a la marea, utilizando un análisis de componentes principales. Se tomaron muestras bimensuales de biomasa de C. canaliculatus desde noviembre de 1988 hasta noviembre de 1989. La biomasa de C. canaliculatus presentó un marcado ciclo estacional, con biomasa máxima en verano (670 g m–2) y mínima en invierno (126 g m–2). El análisis de componentes principales reveló que la biomasa alta (mayor que 543 g m–2) quedó asociada con temperaturas atmosféricas altas (mayor que 21.4ºC) y baja energía del oleaje (menor que 95.7 cm). La biomasa baja (menor que 323 g m–2) estuvo asociada con temperaturas atmosféricas bajas (menor que 17.2ºC) y tiempo de exposición al aire entre 81.5 y 109 h. Los valores de biomasa intermedios (323-543 g m–2) estuvieron asociados con temperaturas del agua altas (mayor que 16ºC).Acceso al recurso -
16617
Effects of formulation and process conditions on chemical composition, color parameters, and acceptability of extruded insect-rich snack
Published 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 -
16618
Resistant starch from plantain (Macho Musa paradisiaca L.) and banana (Roatan Musa sapientum L.) varieties crosslinked with epichlorohydrin
Published 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 -
16619
Descripción de los movimientos verticales y horizontales del tiburón cabeza de martillo, Sphyrna lewini, del sur del Golfo de California, México
Published in Ciencias Marinas (1993)Fuente: Ciencias MarinasTipo de material: Artículo científicoDescripción: Horizontal and vertical movements are described for four scalloped hammerhead sharks (Sphyrna lewini) tagged with ultrasonic transmitters. The trackings were carried out during August 1986, 1988-1989, and July 1989 in the pelagic environment surrounding Espíritu Santo Seamount and Las Animas Island in the southem Gulf of California. The hammerheads generally remained above the seamount and near the island during the day. Fifteen sharks were tracked during homing movements away from and back to the seamount. Of the excursions, 13 were made into the pelagic region during the night and two during the day. The maximum distance moved away from the seamount ranged from 4 to 20 km. Departure and return movements were at times close to and parallel to each other, suggesting that the sharks followed particular routes to preferred feeding sites. The sharks made vertical excursions, ascending and descending in the water column (in yo-yo form). The diving oscillations occurred between 50 to 450 m. These vertical movements were usually below the surface mixed layer and well away from the bottom. The range in water temperatures (2º-6ºC) encountered during these vertical excursions was small in relation to that reported for other species of fishes, suggesting that for this species the function of the excursions may not be thermoregulation. Se proporciona una descripción de los movimientos horizontales y verticales de cuatro tiburones martillo (Sphyma lewini) marcados con transmisores ultrasónicos. El estudio se llevó a cabo en aguas pelágicas que rodean el Bajo Espíritu Santo y la Isla Las Animas, ubicados en el sur del Golfo de California, durante los meses de agosto de 1986, agosto de 1988 y julio y agosto de 1989. Se observó que los tiburones se mantuvieron generalmente sobre el bajo durante el día. Se realizaron quince seguimientos telemétricos de los movimientos de salida y regreso (homing) al bajo. De estos rastreos, trece se llevaron a cabo hacia la región pelágica durante la noche y dos de día. El intervalo de distancia máxima alcanzada fue de 4 a 20 km. Algunos movimientos de salida y regreso fueron próximos y paralelos uno del otro, lo que sugiere que estos tiburones tienen rutas designadas para visitar sus sitios preferenciales de alimento. Los tiburones presentaron movimientos verticales, ascendentes y descendentes (similares a la trayectoria de un yoyo). El intervalo de profundidad de las inmersiones observadas fue de 50 a 450 m. Los movimientos verticales se llevaron a cabo generalmente por debajo de la capa mixta superficial y por encima del fondo marino. Las diferencias de las temperaturas del agua (2º a 6ºC) en que se desplazaron los tiburones durante sus excursiones verticales fueron pequeñas en relación con las observadas en otras especies de peces, lo que sugiere que para el tiburón martillo la función de dichas excursiones no es de termorregulación.Acceso al recurso -
16620
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
Published 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