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18141
Synthesis and characterization of starch-g-PE copolymer using ethylene carbonate
Published 2023Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: The banana starch reaction with polyethylene using ethylene carbonate was carried out by varying the starch/ethylene carbonate mass ratio (50–1000%). The starch-g-PE mass yield reached 89% mass conversion and a grafting yield of 0.52 when a starch/EC = 0.5 ratio was used, while the mass yield decreased until reaching a value of 26% when the starch/EC mass ratio increased. The final product was characterized by different instrumentals techniques to demonstrate copolymerization. The vibration signal of the carbonyl group (C=O) increased as that the starch/EC mass ratio decreased, indicating that the starch polymer chains are chemically interacting with the PE. The chemical bond signal between starch with carbonate group was assigned at δ 4.8 ppm. This modified starch is a material with less thermal stability than banana starch and polyethylene, and its degradation temperature decreases by 20 °C and 50 °C, respectively. The micrographs shown that the starch granules randomly agglomerate due to the presence of PE. Modified starch has a lower crystallinity than native starch. The viscosity of the starch-g-PE granules reached a value of 0.1 Pa s at temperature of 33 °C, while native starch reached a value of 5.0 Pa s at this same temperature. This product obtained is a moisture-resistant material due to the presence of PE chains and that could be used as a compatibilizer for post-consumer polymers such as polyalkanes.Acceso al recurso -
18142
The effect of ethylene glycol on starch-g-PCL graft copolymer synthesis
Published 2016Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: The synthesis of the graft copolymer starch-g-PCL was carried out in a single phase, using molybdenum oxide as a catalyst, at a temperature of 150°C over a period of 24 h. Infrared spectroscopy and nuclear magnetic resonance analyses indicated that the graft copolymer was successfully synthesized, obtaining an 84% conversion yield. The introduction of ethylene glycol to the reaction influences the copolymer synthesis, affecting conversion yields and the physicochemical properties of the resultant copolymer. X-ray diffraction analysis indicates that the copolymer crystallinity decreases as ethylene glycol concentration increases. An investigation of the thermal properties of the graft copolymer suggested that the decomposition temperature of the copolymer, compared to that of the homopolymer, decreases with exposure to ethylene glycol. Scanning electron microscopy revealed the formation of clusters between the starch granules and the grafted copolymer due to the interaction of the hydroxyl groups of the starch and PCL.Acceso al recurso -
18143
Effect of Different Cooking Methods on The Nutritional Composition f Tilapia (Oreochromis Sp.)
Published 2020Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Tilapia (Oreochromis sp.) is a fish that is gaining ground in cultivation and sales because of its nutritional properties: high protein content, vitamins, and minerals with few unhealthy saturated fats as in red meats. This work aimed to evaluate the effect of cooking on the chemical composition, Aw, and pH, in addition to the electrophoretic, and fatty acid profile of the Tilapia using an electric oven, microwave and steaming as cooking methods. The results showed that the nutritional components of Tilapia changed significantly (p<0.05) at two temperatures and at two potencies used. Microwave and steaming preserved better the proteins in the Tilapia after its cooking. Electrophoresis results showed a decrease in intensity and number of bands depending on the type of treatment to which the meat was subjected. On the other hand, the electric oven method at 2 temperatures resulted with the highest increase in essential fatty acids (45% and 36%), with a slight decrease in the ω-6 family, because of a probable hydrolysis or oxidation of the same. The steam cooking showed a slight increase in essential fatty acids, but microwave oven preserved better the proteins, indicating that this could be a good method for cooking Tilapia.Acceso al recurso -
18144
Multiresponse optimization of the extrusion process for ready-to-eat snacks from pineapple byproducts and maize flour
Published 2023Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: This research aimed to optimize the processing conditions to obtain ready-to-eat extruded snacks with a high fiber content from mixtures of pineapple byproduct powder (PBP) and nixtamalized maize flour (PBP-NMF) or maize flour (PBP-MF). The effects of barrel temperature, feed moisture content, and PBP were evaluated. The increase in barrel temperature has a negative effect on the bulk density, the water absorption index, and the texture in both mixtures (PBP-MF and PBP-NMF) and increases the expansion index and the water solubility index in the mixture with MF. The increase in the feed moisture content increased the bulk density and water absorption index in both mixtures and the texture in the mixtures with MF. The increasing PBP decreases the expansion index and increases the water solubility index in both mixtures. The increase in PBP in the mixtures with MF decreases the water absorption index, texture, and bulk density. From the optimization, four products were obtained, two for the NMF mixture and two for the MF mixtures. The optimal formulations can be considered a good source of total fiber (12.46−12.78 g/100 g) and protein (8.27−8.85 g/100 g) with good acceptance by consumers.Acceso al recurso -
18145
Effect of ultrasonic treatment on the morphological, physicochemical, functional, and rheological properties of starches with different granule size
Published 2016Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Sonication (25 kHz) was applied to plantain (large granule size) and taro (small granule size) starches for two treatment durations (20 and 50 min) using a flow-cell at controlled temperature of 4 ± 0.1°C. The granule size distribution of starches was only slightly affected by the ultrasound treatment. Ultrasound affected the granule surface morphology, as reflected by the profound cavities and fractures. Starch with larger granule size was more affected by ultrasound treatment, as reflected by the higher variation in the peak viscosity, swelling power, and solubility. Peak viscosity increased with ultrasound, whereas swelling power and solubility decreased after treatment. Additionally, ultrasound treatment of high granule size starch resulted in a more pronounced decrease in the storage modulus (G′) compared with its native counterpart.Acceso al recurso -
18146
Дослідження механізмів противиразкової активності кріоекстракту плаценти при серотоніновому ульцерогенезі...
Published 2022Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso -
18147
Modification of banana starch (Musa paradisiaca L.) with polyethylene terephthalate: Virgin and bottle waste
Published 2021Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Chemical modification of banana starch (Musa paradisiaca L.) with the degradation products of virgin and bottle waste of polyethylene terephthalate was carried out in situ. The modified starch was characterized by FTIR and NMR, which allowed proposing three chemical structures. SEM micrographs showed that the morphology of the modified starch granule is directly related with mass ratio of Starch/PET and type of PET used in the reaction. The crystallinity of the modified starch decreased up to 92.6% and 62.5% using bottle waste and virgin PET, respectively, according to XRD diffractograms. TGA analysis showed that the starch degradation temperature decreased by 12 °C. Modified starch films were elaborate and its electrical conductivity was found to be 2.9 times compared to that of native starch. The starch/PET film presented the highest value in the mechanical property of elongation at break compared to the starch-only film. The modified starch film was degraded above 80% by aqueous hydrolysis.Acceso al recurso -
18148
Effect of Crushed Glass Cullet Sizes on Physical and Mechanical Properties of Red Clay Bricks
Published 2016Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: This study reports the effect of clear waste glass from bottles added on 20 to 30 wt.% and variable particle size (<500, <300, and<212 𝜇m), into clay mixtures for the handmade brick manufacturing process. The bricks were manufactured with mixtures of clay,crushed glass, and water in different proportions, homogenized, casted in wooden molds, air-dried at room temperature for 72 h,and sintered at 1000∘C for 12 h. Total shrinkage, water absorption, compressive strength, microstructure, and phase composition arediscussed with respect to glass content and its particle size. The results indicate that increasing the content of glass and decreasing itsparticle size enhanced significantly the brick properties of water absorption and compressive strength by up to 18.5% and 6.8 MPa,for bricks with 30 wt% and particle size lower than 212 𝜇m. It is proposed that decreasing the glass particle size its surface areaincreases allowing easier melting of glass by lower energy consumption, reducing porosity and enhancing brick propertiesAcceso al recurso -
18149
Clusters of starch-g-PCL and their effect on the physicochemical properties of films
Published 2017Fuente: Universidad del PapaloapanTipo de material: ArtículoDescripción: Starch-g-PCL films were prepared using the casting method and were characterized by different instrumental techniques and physicochemical properties. Nuclear magnetic resonance and Fourier transform infrared spectroscopy led to the proposal of a chemical structure for the films. The scanning electron microscopy (SEM) images of the films showed the formation of clusters of the graft copolymer starch-g-PCL. The effects of these clusters on the crystallinity (X-ray powder diffraction) revealed that the crystalline zones of the films increased by 46% and the elongation percentage increased by up to 50%. Also, the chemical degradation (aqueous hydrolysis) and the soil degradation of these films were 1.9 and 2.6 times faster than the films of starch alone. However, the thermal degradation temperature of the films decreased by more than 15°C, the moisture content decreased to 6.5%, and the water vapor permeation values increased in the films that contained starch-g-PCL. These results were accentuated with the increase in the amount of starch-g-PCL clusters.Acceso al recurso -
18150
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 -
18151
Opto-Metallurgy and the Photonide Class: Architectural Foundations for Zero-Latency Photonic AI Inference
Published 2026Fuente: ZenodoTipo de material: Recurso digitalAcceso al recurso -
18152
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 -
18153
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 -
18154
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 -
18155
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 -
18156
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 -
18157
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 -
18158
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 -
18159
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 -
18160
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