Revista Mexicana de Ingeniería Química <div class="_4wyf">The Mexican Journal of Chemical Engineering &nbsp;(ISSN 1665-2738,&nbsp; issn-e: 2395-8472) publishes original research papers with the aim of promoting a rapid share of relevant research in various disciplines of Chemical Engineering and its interfaces with other enigineering disciplines. A volume is published each year and it consists of three issues, which are published every four months.&nbsp;</div> en-US <p>By publishing your paper in our journal you are also granting it the copyright of the information that it contains.</p> (Francisco J Valdes Parada) (Francisco J. Valdés-Parada) Tue, 07 Apr 2020 04:47:27 +0000 OJS 60 Effect of incubation conditions on the aerobic pretreatment of the organic solid wastes and the volatile fatty acids production <p>In the present work, the effect of an aerobic pretreatment on the hydrolysis and acidogenesis of the organic solid wastes (OSW) was evaluated. The aerobic pretreatment was carried out under three incubation conditions: the first condition was at 30°C for 24 hours (isothermal), the second condition was at 30°C for 12 hours followed by 12 hours at 35°C, and the third condition was at 35°C for 12 hours followed by 12 hours at 40°C. During the aerobic pretreatment, the enzymatic activity was analyzed and the product obtained from the pretreatment was subsequently fermented in anaerobic hydrolytic leach bed (AHLB) reactors to obtain volatile fatty acids (VFA). The best hydrolysis results were achieved with the aerobic pretreatment at 30°C for 24 hours, obtaining activities of xylanases and pectinases of 115 and 73 U g<sup>-1</sup> dry matter (DM) respectively after 18 hours and 100 U g<sup>-1</sup> DM of proteases at the beginning of the process; values that are 2.7, 2 and 4 times higher than previously report. Also, a hydrolysis constant (<em>k</em>) of 0.081 d<sup>-1</sup> was obtained, with the productivity of VFA of 0.82gLr<sup>-1</sup>d<sup>-1</sup>, with predominance in acetate, the main precursor of methanogenesis in the final stage of anaerobic digestion.</p> J. E. Jimenez-Rodriguez, F. J. Martínez-Valdez, R. Estrada-Martínez, O. Monrroy-Hermosillo, G. Saucedo-Castañeda, F. Ramirez-Vives ##submission.copyrightStatement## Thu, 19 Dec 2019 00:00:00 +0000 Effect of heavy metals and other xenobiotics on biodegradation of waste canola oil by cold-adapted Rhodococcus sp. strain AQ5-07 <p>The Antarctic is generally considered to be one of the most pristine areas in the world. However, both long and short-range pollutants are now known to be present in the Antarctic environment. Canola oil is an example of a polluting hydrocarbon that can be accidentally released into the Antarctic environment in oil wastewater treatment plants. The Antarctic soil bacterial strain <em>Rhodococcus</em> sp. AQ5-07, known to be capable of using waste canola oil (WCO) as its sole source of carbon, was tested for its ability to degrade canola oil in the presence of different heavy metals and xenobiotics. <em>Rhodococcus </em>sp. AQ5-07 was grown on minimum salt media containing different heavy metals (Zn, Co, Ni, Ag, Pb, Cu, Cr, Hg, Cd and As), xenobiotics (acrylamide and phenol) supplemented with 3% WCO. Three out of the 10 heavy metals tested (Hg, Cd and Ag) led a significant reduction in canola oil degradation at a concentration of 1 ppm. The IC50 values of Hg, Cd and Ag were 0.38, 0.45 and 0.32 ppm, respectively. The strain could also withstand 10 mg/L acrylamide, 50 mg/L phenol and 0.5% (v/v) diesel. This study confirmed the ability of <em>Rhodococcus</em> sp. AQ5-07 to degrade canola oil in the presence of various heavy metals and other xenobiotics, supporting its potential use in bioremediation of vegetable oil and wastewater treatments in low temperature environments.</p> S. Ibrahim, A. Zulkharnain, K. N. M. Zahri, G. L.Y. Lee, P. Convey, C. Gomez-Fuentes, S. Sabri, K. A.K. Khalil, S. A. Alias; G. Gonzalez-Rocha; S. A. Ahmad ##submission.copyrightStatement## Sat, 28 Dec 2019 17:48:43 +0000 Trichoderma Asperellum, an inoculant for production of steviol glycoside in Stevia Rebaudiana bertoni plants micropropagated in a temporary immersion bioreactor <p><em>Stevia rebaudiana</em> is a plant that synthesizes steviol glycosides, which are compounds with sweetening properties. The aim of this work was to evaluate the growth-promoting effect of a micropropagation system in a Temporary Immersion Bioreactor (TIB) and the inoculation with <em>Trichoderma asperellum</em> on the <em>S. rebaudiana</em> plants, and to determine their effect on the production of steviol glycosides and phenolic compounds. <em>S. rebaudiana</em> plants with intact roots were obtained using a TIB with Murashigue and Skoog medium and 0.37 mg L<sup>-1</sup> indole butyric acid, and subsequent the plants were inoculated with spores of <em>T. asperellum</em> (4 x 10<sup>4</sup> spores mL<sup>-1</sup>). The growth of plants inoculated with the fungus was significantly larger than the plants uninoculated (control). The plants inoculated produced 3 times more steviol glycosides than the plants uninoculated (control); while, the content of phenolic compounds was similar. These results encourage the possibility of using a TIB and <em>T. asperellum</em> for the propagation and growth promotion of <em>S. rebaudiana</em> plants with high content of steviol glycosides.</p> D. Villamarín-Gallegos, D. G. Oviedo-Pereira, S. Evangelista-Lozano, G. Sepúlveda-Jiménez, J. Molina-Torres, M. Rodríguez-Monroy ##submission.copyrightStatement## Sat, 04 Jan 2020 02:17:19 +0000 Detection of Salmonella enterica on silicon substrates biofunctionalized with anti-Salmonella IgG, analyzed by FTIR spectroscopy <p>Foodborne diseases are considered a health problem, <em>Salmonella</em> is part of the main microorganisms that generate this type of diseases, so its detection requires a short period of time, biosensors can be a good option to meet this need. In this work, three substrates (crystalline and amorphous silicon, hydrogenated amorphous silicon carbide) were biofunctionalized applying self-assembled monolayers technique, presence of characteristic functional groups of the assembly was verified by Fourier transform infrared spectroscopy (FTIR). Anti-<em>Salmonella</em> IgG antibodies against whole bacteria were generated. Second derivative of each FTIR detection spectrum was obtained, having modifications in the zone between 1600-1700 cm<sup>-1</sup> given by the secondary structure of proteins, being crystalline silicon and hydrogenated amorphous silicon carbide platforms, which presented the most notorious bands. Detection was performed on flat substrates with a specific area (25 mm<sup>2</sup>), a detection time of 60 min was stablished and a concentration of 500 CFU/mL was detected. With this, the three silicon and derivatives biofunctionalized may have future applications in food microbial quality monitoring.</p> F. J. Gómez-Montaño, A. Orduña-Díaz, M.C. G. Avelino-Flores, F. Avelino-Flores, F. Ramos-Collazo, C. Reyes-Betanzo, V. López-Gayou ##submission.copyrightStatement## Sun, 12 Jan 2020 23:22:45 +0000 Diagnostic hydrocarbon pollution in Veracruz beaches and airlift bioreactor as suggestion of remediation <p>The aim of the study was identified pollution by hydrocarbons in the beaches adjacent of the port of Veracruz and propose an alternative to bioremediation. Carried out monitoring in the mouths of May and July of 2018, in the water of the beaches near the port of Veracruz, where hydrocarbons were found such as tetracosane (0.24 ± 0.01 mg L<sup>-1</sup>) and benzo(a)pyrene (2.05 ± 1.02 mg L<sup>-1</sup>). For remediation was proposed an airlift bioreactor, in a medium formed by seawater and a nitrogen source, where suspended solids increased until 1.95 ± 0.02 g L<sup>-1</sup>, diesel fell 98% of its initial concentration (1.5 g L<sup>-1</sup>), emulsifying activity reached a value of 1.07 ± 0.01 AE mL<sup>-1</sup> and initial droplet size was 1283.83 ± 76.02 nm and decreased to 677.63 ± 20.28 nm. Also, the bioreactor was assessed without a nitrogen source, suspended solids dropped until 0.02 ± 0.01 g L<sup>-1</sup>, diesel fell 10%, emulsifying activity reached a value of 1.42 ± 0.06 AE mL<sup>-1</sup> and droplet size dropped from 1361.54 ± 7.55 nm to 974.32 ±14.18 nm. The results showed that the bioreactor with nitrogen source is able biodegrade the hydrocarbons found.&nbsp;</p> E. J. Sandoval-Herazo, V. Saucedo-Rivalcoba, B. Gutiérrez-Rivera, R. Hernández-Martínez, M. A. Lizardi-Jiménez ##submission.copyrightStatement## Mon, 13 Jan 2020 17:58:41 +0000 Removal of heavy metals present in groundwater from a northern Mexico mining community using Agave tequilana Weber extracts <p>Groundwater samples from a mining community north of Mexico were studied, concentration of metals above the maximum allowable concentration from Mexican regulation were found. Spherical agglomeration technique (SAT) was used to remove metals (Pb, Cu, Cr, Ni, Zn, Mn, Cd). Two precipitating agents were tested: NaOH and Ca(OH)<sub>2</sub>. Also, <em>Agave tequilana</em> Weber extract as hydrophobicizing agent was employed to avoid metal redisolution. High metal removal proved the effectiveness on SAT application under a pH ranging between 9 and 11 and extract doses from 0.3 g extract/g pollutant. Better removal percentages were reached when using Ca(OH)<sub>2</sub> as precipitating. Reported removal efficiency in that case yielded removal percentages as high as 99% removal for Pb under the three pH tested. The heavy metal evaluation index before treatment was 2354.91, but decreased to levels as low as 4.7 after SAT application.</p> F. A. Alcázar-Medina, C. M. Núñez-Núñez, I. Villanueva-Fierro, C. Antileo, J. B. Proal-Nájera ##submission.copyrightStatement## Mon, 13 Jan 2020 22:53:27 +0000 Termiticidal activity of mycosynthesized silver nanoparticles from Aspergillus fumigatus BTCB15 <p>Termites, due to their feeding behavior are exceedingly disastrous to the community affecting not only the infrastructure of buildings but also responsible in converting fields into barren lands. Though insecticides are used to control termites but it is not an ecofriendly approach. In the current study silver nano particles were produced from <em>Aspergillus fumigatus </em>BTCB10 and its effect was observed in controlling termites. Feeder blocks were treated with different concentrations (0.1, 1, 5, 10 and 15ppm) of nanoparticles and fed to the subterranean termites of <em>Coptotermes sp. </em>for two weeks. Among all the concentrations used 15ppm was the most effective in which 100 % mortality was achieved on the 9<sup>th</sup> day and the mean weight loss of block was 3.3% as compared to control in which it was 32.2%. Among all the concentrations used 0.1 ppm treated blocks were also affected by fungus which showed that higher concentrations were also effective in inhibiting fungal growth. Conclusively, this study showed that mycosynthesized silver nanoparticles are very effective protecting the wood from damaging not only from termite but also from wood deteriorating fungus. Further study should be undertaken to bring this approach at commercial scale.</p> M. Iqtedar, N. Mirza, A. Aihetasham, S. Iftikhar, A. Kaleem, R. Abdullah ##submission.copyrightStatement## Wed, 15 Jan 2020 04:37:25 +0000 Hypomyces chrysospermus ACL-01 isolated from Boletus edulis and its effect against fungal cereal pathogens <p>In this study, a <em>Hypomyces chrysospermus</em> ACL-01 fungus was isolated from the fruiting body of edible basidiomycete <em>Boletus edulis</em>, collected in Acaxochitlán in the State of Hidalgo, Mexico popularly known as tlacoayel. The effect of the isolated fungus against different fungal cereal pathogens was evaluated. The dual confrontation test and scanning electron microscopy analysis revealed that this ascomycete grows on the basidiomycetes <em>Sporisorium reilianum</em> and <em>Tilletia</em> sp., causing loss of cell viability. However, for the ascomycetes <em>Bipolaris sorokiniana</em> and <em>Pyrenophora teres</em> f. <em>teres</em> no effect was observed. On other hand <em>Stenocarpella maydis</em> and <em>Fusarium</em> sp. inhibited the development of <em>H. chrysospermus </em>ACL-01. The isolated strain produced extracellular enzymatic activities of the acid and basic proteases, chitinase and laccase. Cellulase and lipase activities were not found.</p> A. Cartagena-Luna, A.R. Gayosso-Mexia, M.A. Anducho-Reyes, E.O. López-Villegas, Y. Mercado-Flores ##submission.copyrightStatement## Tue, 21 Jan 2020 05:39:56 +0000 In vitro evaluation of the pharmacological properties of crude methanol extract and its fractions of Aconitum austrokoreense aerial parts <p>Although the dried tuberous roots of <em>Aconitum austrokoreense</em> Koidz has been traditionally used to treat various diseases, its aerial part has been considered a useless by-product. In this study, we determined the antioxidant, antimicrobial, anti-inflammatory and anti-cancer activities of the aerial part of <em>A. austrokoreense </em>to assess its potential benefit to human health. The antioxidant activity was analyzed using two different methods, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and reducing power assays and suggested that the crude methanol extract and butanol fraction possessed strong antioxidant activity. Additionally, the aqueous fraction exhibited not only remarkable antimicrobial activity against Gram-negative bacteria but also significant inhibition of lipopolysaccharide-induced nitric oxide production in RAW 264.7 cells and cytotoxic activity against human cancer cell lines. Furthermore, correlation analysis between the polyphenolic content and biological activities of the aerial part of <em>A. austrokoreense </em>suggests that phenolic compounds might be major contributors to the DPPH free radical scavenging and anti-cancer activities. Taken together, these findings suggest that the nonmedicinal parts of <em>A. austrokoreense</em> can also be used as a potential natural resource to develop effective dietary health supplements.</p> H. J. Ju, T.K. Yoo, S. Jin, H. Kim, T. K. Hyun ##submission.copyrightStatement## Mon, 10 Feb 2020 05:24:49 +0000 The green synthesis and characterisation of silver nanoparticles from Serratia spp <p>The biological means of silver nanoparticles synthesis is an evolutionary step in the process of synthesizing nanoparticles to produce particles within the nano range. With the side effects of the use of chemical and physical synthesis methods yielding toxic and unstable, researches have turned to green synthesis to produce nanoparticles using the mechanism of the bacteria specifically the nitrate reductase enzyme present in most bacteria to break down silver nitrate to silver nanoparticles which are stable and reduces the cost of production. Marine bacteria plays it role by being a reservoir that can intake heavy metals and breaking down with no difficulty as a result of their harsh habitat which is rich in heavy metals. This study was done to prove that marine bacteria can synthesize silver nanoparticles and the nanoparticles are stable and has a range of size and shape through preliminary studies. Marine bacteria were isolated from marine soil samples and later identified to belong to the genus <em>Serratia</em>. Synthesis of the nanoparticles were done using extracellular synthesis where equal amounts of bacterial supernatant and 0.5 M silver nitrate was added and incubated under dark condition for 72 hours. 20 isolates showed positive results for synthesis which were further examined using UV-Visible Spectra analysis showing all 20 samples having a range of size and shape of nanoparticles with peaks observed between the ranges of 340 nm to 440 nm, with the sample strain AQ5-NT6 being the most potent. This study will provide fundamental data and add knowledge to the field of green synthesis of silver nanoparticles.</p> C. De Silva, A. A. Mohd Noor, M. M. Abd Karim, B. Gunasekaran, S. Abd Gani, M. A. Cabrera, S. A. Ahmad ##submission.copyrightStatement## Sat, 15 Feb 2020 04:55:08 +0000 Kinetic studies of marine psychrotolerant microorganisms capable of degrading diesel in the presence of heavy metals <p>The presence of heavy metals in Antarctica is an emerging issue as human influence becomes more discernible over the years. The study of pollution in Antarctica can help people to understand the real influence of human activities on the environmental pollution from polar regions. Bioremediation of petroleum hydrocarbons in the polar environment where toxic metals co-existed involves selecting strictly autochthonous Antarctic strains with dual catabolic competence and tolerance to toxic metals. In this study, diesel degradation was observed in the presence of 1 ppm of eight selected heavy metals; Ag, Al, Cd, Co, Cr, Hg, Ni and Zn. Bacterial growth was inhibited in increasing order of Zn&gt; Cr&gt; Cd&gt; Al&gt; Ni&gt; Hg&gt; Co&gt; Ag. Bacterial growth was the highest in Zn at OD<sub>600 </sub>0.556 (P&gt;0.05) and lowest in Ag at OD<sub>600 </sub>0.151 (P&lt;0.05). Diesel degradation was inhibited in the order of Hg&gt; Cr&gt; Al&gt; Zn&gt; Ag&gt; Cd&gt; Ni&gt; Co, which was analysed using gravimetry analysis. Degradation was the highest in Hg at 52.23% (P&gt;0.05) and lowest in Co at 22.76% (P&lt;0.05). This work serves as a pilot study in gathering data to analyse and gather more data for inhibition concentration of heavy metals for the Antarctic marine bacteria.</p> N.N. Zakaria, A.F.A. Roslee, C. Gomez-Fuentes, A. Zulkharnain, M. Abdulrasheed, S. Sabri, N. Ramírez-Moreno, N. Calisto-Ulloa, S.A. Ahmad ##submission.copyrightStatement## Tue, 25 Feb 2020 04:21:19 +0000 Changes in the phenolic compounds profile, antioxidant and anti-melanogenic activity from organs of Petasites japonicas under different extraction methods <p><em>Petasites japonicus</em>, a perennial flowering plant belonging to the Asteraceae family, has long been used in traditional herbal medicine for treating various diseases. The present study was conducted to investigate the effect of extraction methods including microwave-assisted extraction, autoclave-assisted extraction, and hot water extraction on the polyphenolic composition, antioxidant activity, and anti-melanogenic activity of <em>P. japonicus</em> leaves, stems, and roots. In comparison with other samples, leaf extracts exhibited strong DPPH radical scavenging activity, reducing power activity, and hydrophilic oxygen radical scavenging activity. In addition, the leaf extracts significantly suppressed α-MSH-induced melanin synthesis in B16F10 cells. Quantitative real-time PCR, western blot, and cellular reactive oxygen species (ROS) analyses indicated that the anti-melanogenic effect of leaf extracts obtained by hot water extraction may result from the inhibition of ROS generation and the downregulation of tyrosinase expression in B16F10 cells. Furthermore, the extraction methods differentially affected the content of polyphenolic compounds and bioavailability of <em>P. japonicus</em> extracts. Taken together, the antioxidant activity and anti-melanogenic effect of leaf hot water extracts suggest that the leaves of <em>P. japonicus </em>could be a beneficial source of natural antioxidants for skincare products.</p> S. Ji, T.K. Yoo, S. Jin, H.J. Ju, S.H. Eom, J.-S. Kim, T.K. Hyun ##submission.copyrightStatement## Thu, 05 Mar 2020 22:48:32 +0000 Sustainable bioconversion of saccharified agro residues into bioethanol by Wickerhamomyces anomalus <p>Snowballing levels of greenhouse gas emissions and concerns about climate change has led to an ongoing exploration of biofuels. Bioethanol can be obtained from wheat straw and can be readily available as clean fuel for combustion engines. Therefore, <em>Wickerhamomyces anomalus </em>yeast strain IHZ-26 was used to produce bioethanol from sugar solution obtained from enzymatic hydrolysis of&nbsp; wheat straw. Nineteen different fermentation media were used for this purpose in which carbon source employed was sugar solution obtained from enzymatic hydrolysis of&nbsp; wheat straw. Out of which, maximum bioethanol yield (1.09 g/L; p &lt;0.05) was observed in ‘C1 Yeast extract, peptone, glucose’ medium.&nbsp; After optimization of different cultural parameters, surface culture fermentation for 5 days at 25℃ gave maximum results using 2, 1.5 and 2 g of glucose, xylose and ammonium dihydrogen phosphate, respectively. Four hours old inoculum of yeast in a concentration of 3.5% was optimized for maximum bioethanol yield. These optimized parameters resulted in augmented bioethanol production (5.0g/L) by 5.02 folds. This study revelas that <em>W. anomalus </em>IHZ-26 employed was able to covert pentose and hexose sugars simultaneously with efficient ethanol yield.</p> I. U. Haq, A. Tahir, A. Nawaz, Z. Mustafa, H. Mukhtar, A.U. Rehman ##submission.copyrightStatement## Mon, 23 Mar 2020 01:25:50 +0000 Production and characterization of reconstituted strains of Pleurotus spp. cultivated on different agricultural wastes <p>Two reconstituted strains were produced by mating neohaplonts (monokaryons) obtained by chemical dedikaryotization of two parental strains i.e. <em>Pleurotus ostreatus</em> (OS) and <em>Pleurotus djamor</em> (DS). Five monokaryons were recovered employing homogenization time periods between 60 to 90 s, and incubation at 28<sup>o</sup>C in a peptone-glucose solution (PGS) for <em>Pleurotus</em> spp. Mycelial kinetics on MEA and wheat grain were determined using 4 math models, the parental strains on MEA showed μ<sub>max</sub> values between 8.11 and 10.73 mm day<sup>-1</sup> and on wheat grain presented μ<sub>max</sub> values since 0.23 to 9.18 cm<sup>3</sup> day<sup>-1</sup>, while the reconstituted strains on MEA exhibited μ<sub>max </sub>values ranged from 8.68 and 12.93 mm day<sup>-1 </sup>and on wheat grain showed μ<sub>max</sub> values between 0.25 and 9.30 cm<sup>3</sup> day<sup>-1</sup>. The parental and reconstituted strains were cultivated using two agricultural wastes such as wheat straw (WS) and a mixture of oak sawdust, wheat straw, millet seed, cotton seed hull and CaCO<sub>3</sub> (AP). The productivity and chemical composition of the mushrooms, and also the chemical composition of the substrates before and after harvest were determined. Reconstituted strain <em>Pleurotus djamor</em> (DS<sub>2</sub>xDS<sub>4</sub>) cultivated on WS showed the highest biological efficiency (125.84 %) and production rate (2.79 %), and also this strain produced on AP presented the highest productivity parameters: biological efficiency (98.43 %) and productivity rate (2.27 %). The reconstituted strain of <em>Pleurotus ostreatus</em> (OS<sub>4</sub>xOS<sub>5</sub>) produced on AP presented fruit bodies with highest protein content being of 24.03%, while the reconstituted strain of <em>Pleurotus djamor</em> (DS<sub>2</sub>xDS<sub>4</sub>) cultivated on WS exhibited the highest protein content of 32.94%. The substrate AP used in the cultivation of the reconstituted strain (DS<sub>2</sub>xDS<sub>4</sub>) presented the highest biodegradation value of lignin (33.60%).</p> J.D. Valenzuela-Cobos, A. Grijalva-Endara, R. Marcillo-Vallejo, M.F. Garcés-Moncayo ##submission.copyrightStatement## Sat, 28 Mar 2020 19:35:09 +0000 Development and characterization of a dehydrated mixture based on pumpkin flour (Cucurbita maxima) incorporating modified starch of yam (D. alata cv. Diamante 22) with potential application for instantaneous soups <p>In Colombia, food industry seeks the use of raw materials of high nutritional value such as pumpkin (<em>Cucurbita maxima</em>) and yam (<em>Dioscorea alata cv. </em>Diamante 22) for the development of processed foods and diversification of agricultural production. The purpose of this work was to develop a dehydrated mixture using pumpkin flour and modified yam starch. The study included the formulation of dehydrated mixture based on the starch/flour ratio and the type of starch modification. With analysis by infrared spectroscopy (FT-IR) peaks were identified in 1366 – 1367 cm<sup>-1</sup> corresponding to beta-carotene in the flour. With starch modifications gelatinization temperature increased reaching values of 83.6 and 86.3°C. All the rehydrated formulations showed pseudoplastic rheological behavior where the viscosity decreased with the shear rate. The mixture most preferred by consumers and that showed the highest overall desirability (0.47) was the formulation with 60% flour and 10% enzymatically modified starch. Finally, the pumpkin flour conferred favorable sensory characteristics and the starch improved the stability and consistency properties in the prepared product.</p> M. C. Rordriguez-Lora, H. J. Ciro-Velásquez, J. G. Salcedo-Mendoza, T. Serna-Fadul ##submission.copyrightStatement## Tue, 17 Dec 2019 00:00:00 +0000 Effect of sonication on the content of bixin, norbixin, total phenols and antioxidant activity of extracts of five achiote accessions <p><em>Pigments obtained from achiote seeds are highly demanded worldwide, being the bixin the second most important natural pigment. Due to this, the study of methods and conditions that allow to improve&nbsp; traditional processes for their extraction from achiote seeds is of particular interest. In some cases, the functional activity of the obtained extracts is also evaluated. In this work we study the effect of a sonication treatment on the extraction of functional compounds of achiote seeds, as well as the antioxidant activity of such extracts, in comparison to a traditional maceration extraction. Sonication has shown some advantages such as being simple to apply, reducing extraction times and increasing extraction yields. The comparisons are made in hydrophilic and hydrophobic extracts obtained from 5 accessions of achiote from Yucatan, Mexico. When applying sonication, the content of polyphenols (18-25%) and norbixin (25-55%) in the extracts was increased, as well as the antioxidant activity of the hydrophilic (18-22%) and hydrophobic (10-20%) phases; however, the sonication had no effect on the content of bixin, the latter being the main product of commercial interest. These results suggest that sonication extraction can be a valuable alternative for obtaining extracts with higher contents of functional compounds or enhanced norbixin contents from achiote seeds.</em></p> D. R. Goméz-Linton, A. Navarro-Ocaña, S. Alavez, L. Pinzón-López, G.M. Trejo-Aguilar, L. J. Pérez-Flores ##submission.copyrightStatement## Tue, 31 Dec 2019 01:15:55 +0000 Effect of processing parameters on astaxanthin nanoemulsions with stearic acid using ultrasonic emulsification <p>Astaxanthin is a food colorant with exceptional antioxidant activity. Here, nanoemulsions were prepared via an ultrasound emulsification method. We evaluated the effect of lipid concentration (4-7 %), surfactant concentration (0.1-2.0 %), and sonication time (15-30 min) on the particle size while holding astaxanthin content (0.2%) constant. The particle sizing used transmission electron microscopy (Cryo-TEM) and dynamic light scattering including ζ-potential. The antioxidant activity was studied as a function of ABTS<sup>+</sup> radical concentration, and a spectrophotometric method was used to study the stability of the nanoemulsions over time. The increase of the sonication time and the amount of emulsifier reduce the particle size. The best conditions to prepare stearic acid and astaxanthin nanoemulsions were: 4.0% of lipid concentration and 2.0% for surfactant content employing a sonication time of 15.0 min. Having also under these conditions a lower loss of antioxidant activity and greater stability at the end of the storage period against non-emulsified astaxanthin.</p> G. A. Flores-Miranda, J. Yáñez-Fernández, E. San Martin Martinez ##submission.copyrightStatement## Wed, 05 Feb 2020 01:07:06 +0000 Effect of the concentration of starch and clove essential oil on the physicochemical properties of biodegradable films <p>Biodegradable films were obtained with the casting method using different concentrations of purple sweetpotato <em>Ipomoea batatas (L.)</em> starch and clove <em>Syzygium aromaticum (L.)</em> essential oil. Mechanical properties (tensile strength, percentage of elongation and Young's modulus), water vapor permeability and film adsorption isotherms were evaluated. In the formulations containing the intermediate concentrations of the components, a homogeneous surface, an improvement in fracture stress and a decrease in water vapor permeability were observed. The statistical analysis showed a significant difference in the mechanical properties of the composite films (p &lt; 0.05). The GAB model was used to adjust the experimental data of the adsorption isotherms and a higher moisture content of the films containing the highest concentration of starch and essential oil was observed. The F6 (starch 3.5%, clove essential oil 60 mg/L) formulation showed the lowest water vapor permeability values (1x10<sup>-8</sup> g/ m s Pa) and the lowest moisture content in the monolayer, which is considered to be the material with the best characteristics for its possible application, avoiding the excessive use of raw material during its preparation.</p> O.I. Buso-Ríos, G. Velázquez, L. Járquin-Enríquez, N.L. Flores-Marínez ##submission.copyrightStatement## Mon, 10 Feb 2020 03:14:56 +0000 Changes in oxidative stability, composition and physical characteristics of oil from a non-conventional source before and after processing <p>The growing demand for vegetable oils has led to the study of unconventional sources. Buffalo gourd (<em>C. foetidissima</em> Kunth) could be an alternative one. The effect of the refining process on the composition and physicochemical characteristics of the oil, obtained by the soxhlet method and refined by the combined method, was determined. A yield of 34% crude oil was obtained, as well as differences in color (<em>L</em>* from 78.36 to 87.51, <em>b</em>* from 18.52 to 11.31). In the fatty acid profile, unsaturated predominated: 87.97% and 73.20%, respectively. No foreign functional groups were detected, the viscosity changed from 0.045 to 0.062 Pa*s and the oxidative stability decreased markedly in the refined oil. In the sensory test, no difference was identified between fritters obtained with refined buffalo gourd seed oil and those made with commercial canola oil. Due to the composition and characteristics observed, both crude and refined oil could be an alternative for consumption.</p> F. Hernández-Centeno, M. Hernández-González, H.Y. López-De la Peña, R. López-Trujillo, P.B. Zamudio-Flores, E. Ochoa-Reyes, J.M. Tirado-Gallegos, D.G. Martínez-Vázquez ##submission.copyrightStatement## Mon, 24 Feb 2020 22:50:15 +0000 Changes in bioactive compounds content and antioxidant capacity of pecan nuts [Carya illinoinensis (Wangenh. K. Koch)] during storage <p>Pecan nut kernels are rich in health-promoting substances such as unsaturated fatty acids, tocopherols, and phenolic compounds. Due to their importance in the human diet, it is essential to evaluate the effects of drying, and storage temperature and time, on these phytochemicals. Moisture, water activity, lipid content, bioactive compounds concentration, and antioxidant capacity of wet and dry pecan nuts (Western variety) were determined. Then kernels and in-shell nuts were stored (240 days) at 4°C and 25°C, monitoring the changes in tocopherols concentration, phenolic content, and antioxidant capacity. Wet and dry kernels exhibited similar fatty acids profile and γ-tocopherol concentration (20.37±0.73 and 19.27±1.62 mg·100 g<sup>-1</sup> kernels in dry basis), whereas phenolic content and antioxidant capacity decreased due to the drying process (33.2 and 22.3%, respectively). Throughout storage, condensed tannins concentration of kernels and in-shell nuts reduced by 31.5 and 41.8%, while DPPH antioxidant capacity improved 216.4 and 188.4%, respectively. These results evidenced that drying and storage time are the most significant variables regarding pecan nuts postharvest processing; nonetheless, further research related to the relationship between condensed tannins degradation and the increments in DPPH antioxidant capacity is needed.</p> L.M. Rábago-Panduro, O. Martín-Belloso, J. Welti-Chanes, M. Morales-de la Peña ##submission.copyrightStatement## Sat, 07 Mar 2020 00:45:59 +0000 Bio-hydrogen production using metallic catalysts <p>Many applications, including energy applications, require handling pressurized hydrogen gas. However, an alternative option allows the use of a donor that generates hydrogen in situ (either by transfer and / or catalytic reforming), instead of using molecular hydrogen. Ethanol and formic acid, which are biorefinery streams, were used as donors. The effect of metallic catalysts of Pd and Pt, supported on C, g-Al<sub>2</sub>O<sub>3</sub> and zeolite USY, on the generation of hydrogen was evaluated using different ratios between the active phase and the donor, and different times and temperatures of reaction in a high pressure reactor (up to 1000 psi). The catalysts were characterized by DRX, SEM, FTIR and FRX. At the same time, High-Pressure Differential Scanning Calorimetry (HP DSC) was performed for the most promising systems with a ramp of 10 °C/min. Gas chromatography was used to analyze the production of hydrogen. Findings show that the system that generates more hydrogen, with 88%, is 5% Pd/C over 30% formic acid at 300 °C, 500 rpm and a ratio catalyst mass to donor from 1 to 10 (0.028 m).</p> M. A. Mayorga, J. G. Cadavid, O. Y. Suárez, J. C. Vargas, C. J. Castellanos, L. A. Suárez, P. C. Narváez ##submission.copyrightStatement## Tue, 31 Dec 2019 07:55:29 +0000 Sulfate reduction in a sludge gradually acclimated to acetate as the sole electron donor and its potential application as inoculum in a microbial fuel cell <p>The aim of the present work was to obtain a sulfidogenic sludge capable of thriving with acetate and evaluate its potential application as a source of microorganisms in a microbial fuel cell (MFC). The results showed that sulfate (SO<sub>4</sub><sup>-2</sup>) to sulfide (HS<sup>-</sup>) conversion increased from 74 ± 0.39 % with a fed consisting of a mixture acetate:butyrate, to 85 ± 0.34 % with a fed containing only acetate. The sulfate removal rate (SRR) was of 73.14 ± 2.08 mg SO<sub>4</sub>-<sup>2</sup> gVSS<sup>-1 </sup>L<sup>-1</sup> h<sup>-1 </sup>and sulfate reducing activity (SRA) 6.46 ± 1.25 mg COD-H<sub>2</sub>S gVSS<sup>-1</sup>L<sup>-1</sup>h<sup>-1</sup> with the mixture and&nbsp; SRR 70.51 ± 1.58 mg SO<sub>4</sub>-<sup>2</sup> gVSS<sup>-1 </sup>L<sup>-1</sup> h<sup>-1 </sup>; SRA 7.67 ± 1.00 mg COD-H<sub>2</sub>S gVSS<sup>-1 </sup>L<sup>-1 </sup>h<sup>-1</sup> with acetate. The COD removal increased from 66 ± 0.8% with the mixture to 81 ± 0.39 %, with acetate. The open circuit voltage increased from 0.668 to 0.788 V with acetate. The results suggested that this sludge could be utilized to recover energy that could be eventually susceptible to storage for further utilization while reducing sulfate and avoiding accumulation of acetate.</p> J. R. González-Paz, A. Ordaz, J. Jan-Roblero, L. C. Fernández-Linares, C. Guerrero-Barajas ##submission.copyrightStatement## Wed, 18 Dec 2019 00:00:00 +0000 Chitosan films modified with glow discharge plasma in aqueous solution of pyrrole and its evaluation in the removal of red dye no. 2 <p>In this work, the elasticity, morphology and chemical structure of chitosan-glycerol-EDGE films treated with glow discharge plasma (GDP), in an aqueous pyrrole solution for the removal of red dye No. 2, were studied. The treatment of the films with plasma was accomplished supplying 1.57 kV voltage with a current of 0.74 A, while the working frequency was 5.54 kHz. The exposure times of the films to the plasma were 20, 40, and 60 min. Results showed that the stress-strain mechanical properties for an untreated film was 2.6 N with an elongation of 17 mm, while for the treated film was 66 N with an elongation of 6 mm; thus, improving its mechanical properties. The adsorption capacity of films, treated during 40 min at pH close to neutral using a mass of 15 mg, was qe = 757 mg/g. The morphology of the film before its treatment showed a smooth surface; while after treatment, some pores were observed, probably produced by the impact of pyrrole ions onto the surface of the film. The FTIR analysis allowed to identify the functional groups before and after films treatment; it showed a reduction of -OH groups that belongs to chitosan, and the presence of N-H, C-N, and C=C groups, which corresponds to the aromatic ring of the polypyrrole molecule.</p> J. N. Balderas-Gutiérrez, C. Hernández-Tenorio, R. E. Zavala-Arce, J. H. Pacheco-Sánchez, B. García-Gaitán, J. Illescas ##submission.copyrightStatement## Sun, 26 Jan 2020 04:15:00 +0000 Effect of the adsorbent dose in Pb(II) removal by using sugar cane bagasse: Kinetics and isotherms <p>The objective of this work was to evaluate the effect of the adsorbent dose on the removal of lead (II) present in a synthetic solution using sugarcane bagasse (<em>Saccharum officinarum</em>). The biomaterial was characterized before and after removal by FTIR analysis which reported the presence of hydroxyl, carboxyl and carbonyl functional groups; and SEM analysis showing a porous surface in the form of fibrous cylinders typical of lignocellulosic materials, evidencing that Pb (II) ions are captured on the surface of the adsorbent. It was determined that the best dose of adsorbent was 0.10g obtaining 99.68% removal. The results of the kinetics were adjusted by the first order Pseudo model; and the isothermal adsorption that described the process was Langmuir, determining that the process occurs by physic-sorption and monolayer. It is concluded that the residual cane bagasse is efficient for the preparation of adsorbent and is recommended for the removal of the metal ion under study.</p> Candelaria Tejada-Tovar, Humberto Bonilla Mancilla, Jenny Del Pino Moreyra, Angel villabona-ortiz, Rodrigo Ortega Toro ##submission.copyrightStatement## Tue, 03 Mar 2020 04:06:47 +0000 Red dye 40 removal by fixed-bed columns packed with alginate-chitosan sulfate hydrogels <p>Modified Chitosan was used for the removal of red dye 40 from aqueous solutions at a pH of 5.0. The adsorption was carried out making use of fixed-bed columns packed with beads of Alginate-Chitosan Sulfate (Alg-ChS) hydrogels. Two columns with heights of 13 and 33 cm, and two feed rates (20 and 40 mL/h) were used. The pH of the dye solutions at the exit of the columns was much higher than that at the entrance which can be explained by protons transfer from the aqueous solution to the amino and hydroxyl groups of the Alg-ChS and to the carboxilate groups of the alginate. The increase in pH was favorable for the removal of the dye. The breakthrough time and the amount of dye removed decreased when the flow rate was increased. A greater dye removal was achieved when the higher column was used. After the breakthrough time, the columns continued to remove appreciable amounts of dye and even after 50 hours of operation, column saturation was not obtained.</p> I.P. Verduzco-Navarro, C.F. Jasso-Gastinel, N. Rios-Donato, E. Mendizábal ##submission.copyrightStatement## Tue, 03 Mar 2020 05:44:13 +0000 Low temperature hydrochloric acid hydrolysis of corn stover. Kinetic, thermodynamics and characterization <p>Dilute acid hydrolysis at high temperature is one technique to pretreat and produce monomeric sugars from lignocelluloses; however, its main disadvantage is the production of inhibitory aldehydes. In this paper, sugar production was realized by acid hydrolysis of corn stover employing 2.2 M hydrochloric acid solution and low temperature range (60 – 80 ºC). Experimental data were great fitted to different kinetic models, thermodynamic parameters were calculated from first order, Saeman and Saeman biphasic kinetic model, rate constants showed similar values between each other demonstrating that corn stover hydrolysis is an endothermic and non-spontaneous process capable to generate thermodynamically stable products. FTIR and SEM analyses showed the breaking of lignocellulosic matrix and the depolymerization of polysaccharides after acid treatment. The proposed operational conditions were adequate to produce reducing sugars avoiding decomposition into inhibitory aldehydes.</p> <p>&nbsp;</p> J.C. Gómora-Hernández, M. del C. Carreño-de-León, N. Flores-Alamo ##submission.copyrightStatement## Thu, 05 Mar 2020 00:00:00 +0000 Semi-continuous anaerobic co-digestion of vegetable waste and cow manure: a study of process stabilization <p>The anaerobic digestion of vegetable waste (VW) often shows the accumulation of fatty acids and low buffering capacity that promotes instability and low methane productivity. This work evaluated the anaerobic co-digestion of VW with cow manure (CM) as a strategy to improve the process stability. As a reaction system, a 4 L semi-continuous stirred tank reactor with an HRT of 20 days and fed with a substrate formulation of 40 g of VS was used in two periods: 34 days of VW mono-digestion and 26 days of VW:CM co-digestion. The mono and co-digestion processes were numerically evaluated through three analysis tools: a proposed co-digestion model embedded in the Anaerobic Digestion Model No. 1 structure, statistical process control theory, and modeling the pH dynamics as the response of a first-order linear system to an impulse manipulation. The mono-digestion process showed productivity of 0.381 L CH<sub>4</sub> L digester<sup>-1</sup> d<sup>-1</sup>, which increased by 14 % during co-digestion. The results also indicated that in VW:CM co-digestion, the pH dynamics presents a slower response to the daily feed induced by pulses, keeping the values of this parameter within the statistical stability range; as well as the early warning indicator IA/BA (ratio between intermediate and bicarbonate alkalinity) outside the failure thresholds. It was shown that the addition of CM to a mono-digestion of VW increases the buffer capacity of the system and the production of CH<sub>4</sub>, promoting a stable and efficient process.</p> L. R. Miramontes-Martínez, R. Gomez-Gonzalez, J. E. Botello-Álvarez, C. Escamilla-Alvarado, A. Albalate-Ramírez, P. Rivas-García ##submission.copyrightStatement## Mon, 30 Dec 2019 20:11:55 +0000 Development of a process for sugar fortification with vitamin-A <p>A discontinuous cooling crystallization process was developed for sugar fortification with retinyl palmitate seeds (RP, vitamin-A). Saturated sugar solutions at 70 °C were prepared. Different concentrations seeds were added. Linear and natural cooling profiles were induced with stirring speeds of 90 and 180 rpm in batchs of 240 and 300 minutes. Changes in sugar solubility in water, due to RP, were analyzed. At the end of each experiment, the crystals were filtered and dried; the RP concentration, adhered to their faces and encapsulated, was measured and the percentage of degradation was determined. These measurements were repeated during 60 days with the fortified crystals, stored at ambient conditions in paper bags. In addition, organoleptic tests were performed to determine differences in taste against commercial sugar. The results showed that: it was possible to encapsulate the RP seeds to fortify the sugar, the degradation of the RP in the process was less than 32%, there were no significant changes in either solubility or taste and the proposed process increased the shelf life of fortified sugar.</p> P. A. Quintana-Hernandez, D. Maldonado-Caraza, M. C. Cornejo-Serrano, E. B. Villalobos-Oliver ##submission.copyrightStatement## Tue, 31 Dec 2019 01:28:53 +0000 Automation of the successive ionic layer adsorption and reaction -SILAR- process <p>An electromechanical system controlled by a graphic interface developed in a JAVA programming environment was designed and developed, which allows the control of the growth parameters of thin semiconductor films of copper oxides on glass substrates obtained by the SILAR technique. The parameters that can be controlled through the graphical interface are: time, immersion sequence in the solutions and number of cycles. A low-cost microcontroller was used that allowed adapting an electromechanical system with DC motors that locates the substrate holder in the respective chemical solutions The information of the control parameters and the progress of the process can be visualized in any computer system where the developed program be executed. The results obtained show that the SILAR automated system allows obtaining homogeneous thin film deposits. The film thicknesses are controlled by the number of cycles programmed in the SILAR process.</p> J.S. Valdez-Martínez, M.A. Meneses-Arcos, M. Calixto-Rodriguez, J.Y. Rumbo-Morales, M.A. Beltran-Escobar, J. Villanueva-Tavira, E. Sarmiento-Bustos ##submission.copyrightStatement## Tue, 11 Feb 2020 21:59:42 +0000 Effect of thermal and argon plasma treatment in SiO2 spheres, assessing the effectiveness in the elimination of organic waste <p>Cetyltrimethylammonium bromide (CTAB), is a cationic surfactant used in synthesis of silica oxide spheres (SiO2), which can be used in biomedical applications, however, CTAB is cytotoxic and residues can be found within the SiO2 pores, therefore, the removal of CTAB, is crucial. In the present work, the preparation and purification of SiO2 is described. The effect of heat treatment against argon plasma treatment on SiO2 spheres and their efficiency in removing CTAB was analyzed. The plasma treatment was performed using argon, at 50, 100, 150 and 200 W of power, for 1 h, it was also performed at 200 W for 1.5 h. The techniques; DLS, FTIR-ATR, SEM, BET, were used for characterization, in addition to hemolysis studies. The results showed a decrease in surfactant at powers of 150 and 200 W and 1 h. The plasma treatment at 200 W and 1.5 h of treatment, according to the FTIR-ATR, caused a total removal of the surfactant and a 16% increase in the surface area according to the BET analysis, the plasma treatment turned out not to be hemolytic.</p> R. Reyna-Martinez, R.I. Narro-Céspedes, Y.K. Reyes-Acosta, A. Martínez-Luevanos, A. Zugasti-Cruz, M.G. Neira-Velazquez, S. Sánchez-Valdés, G. Soría-Arguello, M.C. Ibarra-Alonso ##submission.copyrightStatement## Mon, 30 Dec 2019 20:23:44 +0000 Resistance of biopolymer capsules to sheep-ruminal fluid <p>The resistance of polymeric capsules in sheep ruminal fluid was evaluated for possible application as a vehicle of bioactive agents to be released in the stage post-ruminal. Capsules were made by ionic gelation, using sodium alginate as wall material in combination with biopolymers and chlorophyll as a bioactive agent. Chlorophyll release and digestibility of biomaterials were evaluated in vitro conditions using sheep-ruminal fluid and digestibility in situ in a sheep with a fistula. The highest rumen digestibility (46.60 ± 3% in vitro and 46.30 ± 3% in situ) and lower release was the alginate-guar gum formulation in deposit-type capsules. It was evidenced that it is possible to use deposit-type capsules, formulated with biopolymers (alginate-xanthan gum or alginate-guar gum) to serve as a possible vehicle for bioactive agents and promoting the post-ruminal release in an ovine model for improvement in the quality of meat for the human consumption.</p> J. B. Ponce-Noguez, L. Alamilla-Beltrán, R. F. Gómez-de-Anda, F. Villalobos-Castillejos, L. Dorantes-Alvarez, B. Nogueda-Torres, V. Pérez-Pérez, O. E. Del Razo-Rodríguez ##submission.copyrightStatement## Wed, 15 Jan 2020 05:13:16 +0000 Erosion behavior of 440C stainless steel cryogenically treated <p>The quality of most of metallic products depends on its superficial condition and how it deteriorates in operation; mostly the type of deterioration phenomena is the principal factor which affects life time and operation performance of machines components. The erosion is one of the most deteriorating factors which metals are exposed to. In the present work, erosion by solid particle tests of martensitic 440C stainless steel were realized. Silica sand (SiO<sub>2</sub>) was used as erodent at four impact angles and four impact speed of the particles. Graphs of erosion show a brittle behavior tendency. The erosion marks were mapped by 3D profilometry, showing that there is no correspondence between the angle of maximum mass loss and the angle at which maximum penetration marks were observed at 5 and 10 psi. Scanning electron microscopy was used to determine the erosion mechanisms for each impact angle test. These results are compared to similar studies in which some behavior differences are reported.</p> J. Ibarra, E. Rodríguez, M. A. González, S. López Cuenca, A. Medina, G. I. Vásquez ##submission.copyrightStatement## Tue, 21 Jan 2020 05:27:49 +0000 A new route for the synthesis of Sn3Sb2S6 thin films by chemical deposition <p>In this work, SnS-Sb<sub>2</sub>S<sub>3</sub> stack films were formed by sequential chemical deposition, and then they were annealed in a nitrogen atmosphere to synthesize Sn<sub>3</sub>Sb<sub>2</sub>S<sub>6</sub> thin films successfully.&nbsp; The structural and optical properties were studied by X-ray diffraction and transmittance and reflectance. All the samples show a high absorption coefficient of &gt; 10<sup>5 </sup>cm<sup>-1</sup> in the visible region. Their optical bandgap and refractive index are between 1.6-1.8 eV and 3.00-2.71, respectively, which decrease with the increase of film thickness. The electrical conductivity is in the range of 10<sup>-8</sup> to 10<sup>-7</sup> Ω<sup>−1</sup> cm<sup>−1</sup>. The light-generated current density (<em>J<sub>L</sub></em>) is presented as a function of Sn<sub>3</sub>Sb<sub>2</sub>S<sub>6</sub> film thickness when exposed to air mass 1.5 global (AM1.5G) and solar radiation intensity of 1000 W/m<sup>2</sup>. In short, Sn<sub>3</sub>Sb<sub>2</sub>S<sub>6</sub> thin films obtained <em>via</em> the proposed new route exhibit appropriate properties for solar cell applications.</p> E. Barrios-Salgado, Y. Rodríguez-Lazcano, J. P. Pérez-Orozco, A. R. Garcia-Angelmo ##submission.copyrightStatement## Sun, 16 Feb 2020 03:38:12 +0000 Formulation and ex vivo skin permeation of lidocaine HCl topical gels using dillenia (Dillenia indica L.) fruit gum <p><em>Current work was endeavoured to formulate the topical gels of 4 % lidocaine HCl by employing dillenia (Dillenia indica L.,) fruit gum (DG) extracted from ripen fruits (14.73% yield). Physicochemical properties such as colour, odour, taste, aqueous solubility, pH and viscosity of this extracted DG were evaluated. Occurrence of carbohydrates and mucilage was confirmed by phytochemical identification tests and was characterized by employing FTIR and 1H NMR spectroscopy. Employing extracted DG along with Carbopol 940 (as gel-forming materials), propylene glycol (as plasticizer), methyl paraben (as preservative) and menthol (as permeation enhancer), topical gels containing 4 % lidocaine HCl were formulated. The pH and viscosity of these gels were satisfactory. The ex vivo skin permeation of lidocaine HCl across excised porcine ear skin membrane from formulated and marketed topical gels containing 4 % lidocaine HCl exhibited sustained permeation over 7 h. Highest lidocaine HCl permeation flux (1589.66 ± 13.36 µg/cm2/h) was measured for the gel containing 0.1 % menthol. Korsmeyer-Peppas model was found as the best-fitting drug permeation model (R2 = 0.9944-0.9992) with super case-II transport mechanism (n = 0.97-1.07). These topical gels of lidocaine HCl (4 %) were found physically stable enough without syneresis in the freeze thaw cycling process.</em></p> M.S. Hasnain, P. Rishishwar, S. Ali, S. Alkahtani, M. Tabish, M. Milivojevic, M.T. Ansari, A.K. Nayak ##submission.copyrightStatement## Fri, 20 Mar 2020 03:28:41 +0000 Effect of thermal treatment of activated carbon fiber felt for reuse in removal of methylene blue from a synthetic wastewater <p>This work proposes reusing based acrylonitrile activated carbon fiber felt (ACFF) for the removal (adsorption) of a cationic dye (methylene blue, MB) from synthetic wastewater. After every removal process, ACFF was thermally treated (calcinated) for reuse. The surface morphology was characterized by high-resolution scanning electron microscopy (HRSEM), and Fourier transform infrared spectroscopy (FTIR) analysis helped to identify functional groups that allowed adsorption process. Batch experiments were carried out at 27 °C with a pH of 10. Results revealed that after calcination, the MB adsorbed turned to carbon deposits, which desorbed during others removal processes, this allowed reusing of ACFF for several adsorption cycles with no significant change in adsorption capacity. The adsorption data followed Langmuir isotherm with the kinetics of pseudo-first-order, which suggests that chemisorption was carried on for removal of MB. The novelty of this work focuses on reusing, through calcination of ACFF, which allows removal efficiency more than 99% up to ten cycles, whereby removal of methylene blue from wastewater by activated carbon fiber felt could be cheaper than other proposed methods.</p> O.G. Rojas-Valencia, M. Estrada-Flores, C.M. Reza-San-Germán, J. Hernández-Fuentes ##submission.copyrightStatement## Tue, 31 Mar 2020 03:21:02 +0000 Active biodegradable films based on thermoplastic starch and poly (e-caprolactone): technological application of antioxidant extracts from rice husk <p>Films of a polymeric material based on cassava starch and poly ε-caprolactone (PCL) were made, with antioxidant properties. The influence of PCL and the antioxidant extract were evaluated, over the mechanical, thermal and chemical properties of the films. These were elaborated with, and without the antioxidant extract, which is rich in polyphenolic compounds.&nbsp;&nbsp;&nbsp;The films were conditioned at 20°C and 53% RH. The antioxidant extract was obtained from rice husk, by the hot water methodology in a high-pressure reactor, at 160°C and 10 bar. The total phenolic content of the extract was 12.27 (mEAG/100g dry matter), and the antioxidant activity had a value of 6691.95 (mETRX/100g dry matter). The extract was incorporated into a thermoplastic starch and poly E-caprolactone matrix, and films by compression molding were obtained. The antioxidant capacity was evaluated by DPPH method, where the lesser value was 1.54 (kg film/g DPHH) from EC<sub>50</sub>, it was found that the addition of PCL and antioxidant improved the general properties of the films.</p> N. Piñeros-Guerrero, Y. Piñeros-Castro, R. Ortega-Toro ##submission.copyrightStatement## Mon, 30 Dec 2019 18:54:49 +0000 Effect of the preparation method on the properties of nanocomposites based on chitosan, montmorillonite and essential oils <p>The aim of this study was to know if the addition order of the components in the film forming solution can modify the characteristics of the final film in order to obtain films with improved physical properties intended for packaging applications, Chitosan films (CH) at 1% were elaborated with montmorillonite (MMT) at 10%, essential oils (cinnamon CEO, and thyme TEO) at 1.5% and glycerol. Two methodologies were used: adding MMT at the beginning (M1) or at the end (M2) of the film preparation process. Water vapor permeability (WVP), mechanical properties, solubility (S), x-ray diffraction (XRD), FTIR and contact angle were evaluated. The combined effects of MMT and CEO using M1 produced films with lower WVP and higher tensile strength compared with M2, probably because MMT in M1 had more time in contact with CH than in M2. Also, SEM display a more compact structure in films using M1 with CEO. X-ray diffraction show that films with M1 were exfoliated while with M2 had an intercalated structure. Therefore, CH films with CEO prepared following the M1 process had more suitable properties to be used as a packaging material for food preservation.</p> C. A. Romero-Bastida, G. Velazquez, S. Bautista-Baños ##submission.copyrightStatement## Wed, 15 Jan 2020 06:19:50 +0000 Predicting the thermal conductivity of composites based on high density polyethylene-cold plasma modified graphite by application of several analytical micromechanical models <p>The experimental data of the thermal conductivity of high density polyethylene composites filled with as-received and modified graphite particles by ethylene plasma polymerization were compared with the theoretical values obtained after applying the following micromechanical analytical models: the series model, the Maxwell model, as well as the Nielsen and the Agari models. The experimental thermal conductivity of the composites was determined by Modulated Differential Scanning Calorimetry. The theoretical results of each model adjusted to a greater or lesser extent to the experimentally obtained data. However, the Agari’s model was the one that most closely approximates the experimental values while the series model is the one with the least precision.</p> G. Soria-Arguello, M.G. Neira-Velázquez, L.F. Ramos de Valle, J.J. Borjas-Ramos ##submission.copyrightStatement## Mon, 30 Mar 2020 21:17:55 +0000 Decentralized robust tube-based model predictive control: Application to a four-tank -system <p>This paper presents a decentralized model predictive controller for nonlinear systems that considers interaction between control inputs. The controller is based on a centralized robust tube-based nonlinear model predictive controller. The main contribution is a procedure to split the process model into s subsystems in order to construct s robust tube-based controllers ensuring a bounded linearization error. In order to show the applicability and&nbsp;effectiveness of the development, the proposed controller is tested on a coupled-tank system and the results are compared with a centralized nonlinear model predictive controller.</p> F. D.J. Sorcia-Vázquez, C. D. García-Beltrán, G. Valencia-Palomo, J. A. Brizuela-Mendoza, J. Y. Rumbo-Morales ##submission.copyrightStatement## Sat, 11 Jan 2020 03:16:47 +0000 Simulation of concentration and incineration as an alternative for vinasses' treatment <p>In the present work the possibility of the concentration and incineration of the vinasse obtained in a Cuban rum factory was evaluated as an alternative for its treatment and to generate electricity. Simulation with ASPEN PLUS v7.2 was used as process analysis tool. A simulation model of the concentration process was obtained and models reported by the literature were used to simulate the incineration and generation of electricity. The model was validated with the real data of the process with a maximum validation error 5,5 % for the total condensates. The necessary conditions were determined to increase the final concentration of the vinasse up to 60 ºBrix. The flow of concentrated vinasse was reduced by 48%, the problem of production shutdowns due to the unavailability of stillage storage was solved and 87 kg/h of potassium rich ash and 632 kW of electric power were obtained. Likewise, an economic analysis was carried out that demonstrated the feasibility of applying the proposed technology.</p> A. Noa-Bolaño, O. Pérez-Ones, L. Zumalacárregui-de Cárdenas, J.L. Pérez-de-los-Ríos ##submission.copyrightStatement## Tue, 21 Jan 2020 05:11:10 +0000