Valorization of Aloe vera Skin By-Products to Obtain Bioactive Compounds by Microwave-Assisted Extraction: Antioxidant Activity and Chemical Composition

Aloe vera skin (AVS) is a major by-product of Aloe processing plants all over the world. In this study, response surface methodology was used to optimize microwave-assisted extraction (MAE) of bioactive compounds from AVS. The influence of extraction parameters, such as ethanol concentration (%Et), extraction temperature (T), time (t) and solvent volume (V), on extraction yield (Y), total phenolic content (TPC), antioxidant activity (DPPH and FRAP methods) and aloin content, was studied. Optimum extraction conditions were determined as 80% ethanol, 80 °C, 36.6 min and 50 mL and optimized extracts showed interesting contents of polyphenols and antioxidant performance. The phenolic profile was determined by HPLC-DAD/MS and some major phenolic compounds, such as aloin A, aloin B, aloesin, aloe-emodin, aloeresin D, orientin, cinnamic acid and chlorogenic acid, were quantified while eight other compounds were tentatively identified. Moreover, structural and thermal properties were studied by FTIR and TGA analyses, respectively. The obtained results suggested the potential of AVS as a promising source of bioactive compounds, thus increasing the added value of this agricultural waste.Authors would like to acknowledge Consellería de Educación, Investigación, Cultura y Deporte de la Generalitat Valenciana (GRISOLIAP/2016/081) and Spanish Ministry of Science and Innovation (Refs. PID2020-116496RB-C21, PDC2021-121345-C21) for their financial support

Recovery of Antioxidants from Tomato Seed Industrial Wastes by Microwave-Assisted and Ultrasound-Assisted Extraction

Tomato seed (TS) wastes are obtained in large amounts from the tomato processing industry. In this work, microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) of antioxidant compounds from TS were optimized by using response surface methodology. The effect of MAE and UAE main extraction parameters was studied on total phenolic content (TPC) and antioxidant activity (DPPH) responses. Antioxidant, structural, morphological, and thermal properties of MAE and UAE extracts were evaluated. A great influence of ethanol concentration was observed in both extraction methods. Optimal MAE conditions were determined as 15 min, 80 °C, 63% ethanol and 80 mL, with a desirability value of 0.914, whereas 15 min, 61% ethanol and 85% amplitude (desirability = 0.952) were found as optimal conditions for UAE. MAE extracts exhibited higher TPC and antioxidant activity values compared to UAE (1.72 ± 0.04 and 1.61 ± 0.03 mg GAE g TS−1 for MAE and UAE, respectively). Thermogravimetric analysis (TGA) results suggested the presence of some high molecular weight compounds in UAE extracts. Chlorogenic acid, rutin and naringenin were identified and quantified by HPLC-DAD-MS as the main polyphenols found by MAE and UAE, showing MAE extracts higher individual phenolics content (1.11–2.99 mg 100 g TS−1). MAE and UAE have shown as effective green techniques for extracting bioactive molecules with high antioxidant activity from TS with high potential to be scaled-up for valorizing of TS industrial wastes.This research was funded by the Bio-Based Industries Joint Undertaking under the European Union Horizon 2020 research program (BBI-H2020), ECOFUNCO project, grant number G.A 837863

Valorization of Agro-Industrial Wastes by Ultrasound-Assisted Extraction as a Source of Proteins, Antioxidants and Cutin: A Cascade Approach

The use of agro-industrial wastes to obtain compounds with a high added-value is increasing in the last few years in accordance with the circular economy concept. In this work, a cascade extraction approach was developed based on ultrasound-assisted extraction (UAE) for tomato, watermelon, and apple peel wastes. The protein and antioxidant compounds were obtained during the first extraction step (NaOH 3 wt.%, 98.6 W, 100% amplitude, 6.48 W/cm2, 6 min). The watermelon peels (WP) showed higher proteins and total phenolic contents (857 ± 1 mg BSA/g extract and 107.2 ± 0.2 mg GAE/100 g dm, respectively), whereas the highest antioxidant activity was obtained for apple peels (1559 ± 20 µmol TE/100 g dm, 1767 ± 5 µmol TE/100 g dm, and 902 ± 16 µmol TE/100 g dm for ABTS, FRAP and DPPH assays, respectively). The remaining residue obtained from the first extraction was subsequently extracted to obtain cutin (ethanol 40 wt.%, 58 W, 100% amplitude, 2 W/cm2, 17 min, 1/80 g/mL, pH 2.5). The morphological studies confirmed the great efficiency of UAE in damaging the vegetal cell walls. WP showed a higher non-hydrolysable cutin content (55 wt.% of the initial cutin). A different monomers’ profile was obtained for the cutin composition by GC-MS, with the cutin from tomato and apple peels being rich in polyhydroxy fatty acids whereas the cutin extracted from WP was mainly based on unsaturated fatty acids. All of the cutin samples showed an initial degradation temperature higher than 200 °C, presenting an excellent thermal stability. The strategy followed in this work has proved to be an effective valorization methodology with a high scaling-up potential for applications in the food, pharmaceutical, nutraceutical, cosmetics and biopolymer sectors.This research was funded by the Bio-Based Industries Joint Undertaking under the European Union Horizon 2020 research program (BBI-H2020), ECOFUNCO project, grant number G.A 837863

Emulsions Incorporated in Polysaccharide-Based Active Coatings for Fresh and Minimally Processed Vegetables

The consumption of minimally processed fresh vegetables has increased by the consumer’s demand of natural products without synthetic preservatives and colorants. These new consumption behaviors have prompted research on the combination of emulsion techniques and coatings that have traditionally been used by the food industries. This combination brings great potential for improving the quality of fresh-cut fruits and vegetables by allowing the incorporation of natural and multifunctional additives directly into food formulations. These antioxidant, antibacterial, and/or antifungal additives are usually encapsulated at the nano- or micro-scale for their stabilization and protection to make them available by food through the coating. These nano- or micro-emulsions are responsible for the release of the active agents to bring them into direct contact with food to protect it from possible organoleptic degradation. Keeping in mind the widespread applications of micro and nanoemulsions for preserving the quality and safety of fresh vegetables, this review reports the latest works based on emulsion techniques and polysaccharide-based coatings as carriers of active compounds. The technical challenges of micro and nanoemulsion techniques, the potential benefits and drawbacks of their use, the development of polysaccharide-based coatings with natural active additives are considered, since these systems can be used as alternatives to conventional coatings in food formulations.This research was funded by the Spanish Ministry of Science, Innovation and Universities (MAT2017‐84909‐C2‐1‐R) and Generalitat Valenciana (IDIFEDER/2018/007)

Tannin-modified soybean protein concentrate for wood adhesive

[EN] Soybean protein concentrate (SPC) modified with condensed mimosa tannin (CT) were employed as eco-friendly and formaldehyde-free adhesives for glued-wood joints. Eucalyptus grandis wood boards free of knots and cracks were used as substrate. Thermogravimetric analysis (TGA) showed that tannin provided higher thermal stability to the adhesive, which allowed expanding the temperature range for hot pressing. Apparent viscosity and dynamic angle contact were measured to evaluate the influence of tannin content on rheological behaviour and the wettability process. A classic shear-thinning behaviour was observed for all adhesives. Apparent viscosity and equilibrium contact angle reached a maximum value for low CT content. This effect was attributed to the existence of associative interactions between CT and SPC. Bonding quality parameters (wood failure percentage and shear strength) of the glued-wood joints were measured according to EN 302-1:2004 standard. 1 % CT w/w on SPC adhesive showed the best performance for dry conditions. These adhesives were suitable for glued-wood joints for indoor environments.This work was supported by the Agencia Nacional de promoción Científica y Tecnológica (ANPCyT) under Grant PICT 2016 0445; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Universidad Nacional de Mar del Plata (UNMdP). A special thanks to Mr. Cesar Bovino (Aserradero Ubajay) for providing the wood.Esposito, L.; Ciannamea, EM.; Solaberrieta, I.; Piter, JC.; Ruseckaite, RA.; Stefani, PM. (2022). Tannin-modified soybean protein concentrate for wood adhesive. Journal of Applied Research in Technology & Engineering. 3(1):1-7. https://doi.org/10.4995/jarte.2022.15962OJS1731Aydin, I., & Colakoglu, G. (2007). 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Journal of the American Oil Chemists' Society, 89(9), 1733-1741. https://doi.org/10.1007/s11746-012-2058-2Ciannamea E M, Marin D C, Ruseckaite R A and Stefani P M (2017) Particleboard based on rice husk: effect of binder content and processing conditions J. Renew. Mater 5 19-22. https://doi.org/10.7569/JRM.2017.634125Chalapud, M. C.; Herdt, M.; Nicolao, E. S.; Ruseckaite, R. A.; Ciannamea, E. M.; Stefani, P. M. (2020). Biobased particleboards based on rice husk and soy proteins: Effect of the impregnation with tung oil on the physical and mechanical behavior. Constr Build Mater. 230: 116996. https://doi.org/10.1016/j.conbuildmat.2019.116996Damodaran, S.; Zhu, D. (2016) A formaldehyde-free water-resistant soy flour-based adhesive for plywood. J. Am. Oil. Chem. Soc. 93, 1311-1318. https://doi.org/10.1007/s11746-016-2866-xde Freitas, V., & Mateus, N. (2012). Protein/polyphenol interactions: past and present contributions. Mechanisms of astringency perception. 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(2007), Steady state flow behaviors of extruded blend of rice flour and soy protein concentrate, Food Chemistry, 101, 241 - 247. https://doi.org/10.1016/j.foodchem.2006.01.043Hojilla-Evangelista, M. P. (2010). Adhesion properties of plywood glue containing soybean meal as an extender. Journal of the American Oil Chemists' Society, 87(9), 1047-1052. https://doi.org/10.1007/s11746-010-1586-xHunt, C. G.; Frihart, C. R.; Dunky, M.; Rohumaa, A. (2018). Understanding wood bonds-going beyond what meets the eye: a critical review. Reviews of Adhesion and Adhesives, 6(4), 369-440. https://doi.org/10.7569/RAA.2018.097312Jang, Y., Li, K. (2015). An All-Natural Adhesive for Bonding Wood. Journal of the American Oil Chemists' Society, 92(3), 431-438. https://doi.org/10.1007/s11746-015-2610-yKhosravi, S., Nordqvist, P., Khabbaz, F., Öhman, C., Bjurhager, I., & Johansson, M. (2015). Wetting and film formation of wheat gluten dispersions applied to wood substrates as particle board adhesives. European Polymer Journal, 67, 476-482. https://doi.org/10.1016/j.eurpolymj.2014.11.034Leiva, P., Ciannamea, E., Ruseckaite, R. A., & Stefani, P. M. (2007). Medium-density particleboards from rice husks and soybean protein concentrate. Journal of Applied Polymer Science, 106(2), 1301-1306. https://doi.org/10.1002/app.26545Lin, H., & Gunasekaran, S. (2010). Cow blood adhesive: Characterization of physicochemical and adhesion properties. International Journal of Adhesion and Adhesives, 30(3), 139-144. https://doi.org/10.1016/j.ijadhadh.2009.10.003Liu C, Zhang Y, Li X, Luo J, Gao Q, Li J,(2017) Green bio-thermoset resins derived from soy protein isolate and condensed tannins, Industrial Crops and Products, 108, 363-370. https://doi.org/10.1016/j.indcrop.2017.06.057Mo, X., Cheng, E., Wang, D., & Sun, X. S. (2003). Physical properties of medium-density wheat straw particleboard using different adhesives. Industrial Crops and Products, 18(1), 47-53. https://doi.org/10.1016/S0926-6690(03)00032-3Nicolao, E.; Leiva, P.; Chalapud, M.; Ruseckaite, R.; Ciannamea, E.; Stefani, P. (2020). Flexural and tensile properties of biobased rice husk-jute-soybean protein particleboards. J. Build. Eng.: 101261. https://doi.org/10.1016/j.jobe.2020.101261Nordqvist, P., Nordgren, N., Khabbaz, F., & Malmström, E. (2013). Plant proteins as wood adhesives: Bonding performance at the macro-and nanoscale. Industrial Crops and Products, 44, 246-252. https://doi.org/10.1016/j.indcrop.2012.11.021Ozdal, T., Capanoglu, E., & Altay, F. (2013). A review on protein-phenolic interactions and associated changes. Food Research International, 51(2), 954-970. https://doi.org/10.1016/j.foodres.2013.02.009Peña, C., De la Caba, K., Eceiza, A., Ruseckaite, R., & Mondragon, I. (2010). Enhancing water repellence and mechanical properties of gelatin films by tannin addition. Bioresource Technology, 101(17), 6836-6842. https://doi.org/10.1016/j.biortech.2010.03.112Ping, L., Pizzi, A., Guo, Z. D., & Brosse, N. (2012). Condensed tannins from grape pomace: characterization by FTIR and MALDI TOF and production of environment friendly wood adhesive. Industrial Crops and Products, 40, 13-20. https://doi.org/10.1016/j.indcrop.2012.02.039Piter, J.C, Calvo, C.F., Gonzalez, A.A., Sosa Zitto, M.A., Stefani, P.M. Torrán, E.A. Villalba D.I. (2007) Resistencia a cizalladura en juntas de eucalyptus grandis y pinus elliottii del noreste de argentina encoladas con adhesivo estructural Floresta, 37, 231-237. https://doi.org/10.5380/rf.v37i2.8653Solt, P., Konnerth,J., Gindl-Altmutter, W., Kantner, W., Moser, J., Mitter, R., Hendrikus, van Herwijnen, W.G. 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Valorization of Tomato Seed By-Products as a Source of Fatty Acids and Bioactive Compounds by Using Advanced Extraction Techniques

In this work, lipids and bioactive compounds from tomato seed by-products were extracted and compared by using advanced extraction techniques, such as microwave-assisted extraction (MAE) and supercritical fluid extraction (SFE). The influence of different extraction parameters, including extraction temperature (T), time (t) and solvent volume (V) for MAE as well as extraction temperature (T), pressure (P) and flow rate (F) for SFE-CO2, was evaluated on tomato seed oil (TSO) yield and fatty acids composition using response surface methodology (RSM). Optimum extraction conditions for MAE were 56.2 °C, 29.0 min, and 67.6 mL, whereas conditions of 60.2 °C, 400.0 bar, and 64.6 g min−1 were found for SFE-CO2. Under these conditions, higher TSO extraction yields were obtained by MAE compared to SFE-CO2 (25.3 wt% and 16.9 wt%, respectively), while similar fatty acids profiles were found by GC in terms of FAMEs composition: methyl palmitate, methyl stearate, methyl oleate, and methyl linoleate, accounting for around 80 wt% of unsaturated fatty acids. TSO MAE extracts showed high DPPH• radical scavenging activity which was related to the presence of tocopherols; in particular γ-tocopherol, which was found as the dominant homologue (260.3 ± 0.6 mg kgTS−1) followed by a lower amount of α-tocopherol (6.53 ± 0.12 mg kgTS−1) by HPLC-DAD. The obtained results suggested that tomato seeds are an interesting source of bioactive compounds with potential use in a wide range of nutritional and food applications, increasing the added value of this by-product, which is currently underexploited.This research was funded by the Bio-Based Industries Joint Undertaking under the European Union Horizon 2020 research program (BBI-H2020), ECOFUNCO project, grant number G.A 837863

Encapsulation of Bioactive Compounds from Aloe Vera Agrowastes in Electrospun Poly (Ethylene Oxide) Nanofibers

Aloe Vera is an ancient medicinal plant especially known for its beneficial properties for human health, due to its bioactive compounds. In this study, nanofibers with antioxidant activity were successfully obtained by electrospinning technique with the addition of a natural Aloe Vera skin extract (AVE) (at 0, 5, 10 and 20 wt% loadings) in poly(ethylene oxide) (PEO) solutions. The successful incorporation of AVE into PEO was evidenced by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA) and antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging (ABTS) and ferric reducing power (FRAP) assays. The incorporation of AVE introduced some changes in the PEO/AVE nanofibers morphology showing bimodal diameter distributions for AVE contents in the range 10-20 wt%. Some decrease in thermal stability with AVE addition, in terms of decomposition onset temperature, was also observed and it was more evident at high loading AVE contents (10 and 20 wt%). High encapsulation efficiencies of 92%, 76% and 105% according to DPPH, FRAP and ABTS assays, respectively, were obtained at 5 wt% AVE content, retaining AVE its antioxidant capacity in the PEO/AVE electrospun nanofibers. The results suggested that the obtained nanofibers could be promising materials for their application in active food packaging to decrease oxidation of packaged food during storage.Authors would like to thank Spanish Ministry of Science, Innovation and Universities (MAT2017-84909-C2-1-R), Generalitat Valenciana (IDIFEDER/2018/007) and Consellería de Educación, Investigación, Cultura y Deporte de la Generalitat Valenciana (GRISOLIAP/2016/081 and BEFPI/2018/041) for supporting this research

Visión del alumnado de ciencias sobre empleabilidad, formación e inserción laboral

Uno de los puntos fundamentales de un título universitario es la empleabilidad de sus egresados. La viabilidad de estos proyectos educativos y el posicionamiento de estos en listas de prestigio nacionales e internacionales hacen necesaria trabajar en estructuras sólidas que garanticen la formación del alumnado, la empleabilidad de los egresados, y por tanto su inserción al mundo laboral. Por tanto, la inserción en el mercado laboral puede considerarse clave y de ahí que en las instituciones universitarias se impulsen iniciativas dirigidas a su logro. En este proyecto se planteó conocer el grado de implementación de la oferta de prácticas de diferentes grados tomando como evidencia los resultados académicos e indicadores de calidad con el objetivo de detectar punto débiles y posibles estrategias metodológicas que afiancen la empleabilidad del alumnado. Se considera que es necesario la evaluación y comparación de la visión que tiene el alumnado en relación con la oferta de prácticas para poder establecer nuevos planes de trabajo, nuevas estrategias de formación en empleabilidad o en competencias fundamentales que les ayuden a ser capaces de escoger la opción de prácticas que más de adapte a sus necesidades o sus metas

Valorization of Agro-Industrial Wastes by Ultrasound-Assisted Extraction as a Source of Proteins, Antioxidants and Cutin: A Cascade Approach

The use of agro-industrial wastes to obtain compounds with a high added-value is increasing in the last few years in accordance with the circular economy concept. In this work, a cascade extraction approach was developed based on ultrasound-assisted extraction (UAE) for tomato, watermelon, and apple peel wastes. The protein and antioxidant compounds were obtained during the first extraction step (NaOH 3 wt.%, 98.6 W, 100% amplitude, 6.48 W/cm2, 6 min). The watermelon peels (WP) showed higher proteins and total phenolic contents (857 ± 1 mg BSA/g extract and 107.2 ± 0.2 mg GAE/100 g dm, respectively), whereas the highest antioxidant activity was obtained for apple peels (1559 ± 20 µmol TE/100 g dm, 1767 ± 5 µmol TE/100 g dm, and 902 ± 16 µmol TE/100 g dm for ABTS, FRAP and DPPH assays, respectively). The remaining residue obtained from the first extraction was subsequently extracted to obtain cutin (ethanol 40 wt.%, 58 W, 100% amplitude, 2 W/cm2, 17 min, 1/80 g/mL, pH 2.5). The morphological studies confirmed the great efficiency of UAE in damaging the vegetal cell walls. WP showed a higher non-hydrolysable cutin content (55 wt.% of the initial cutin). A different monomers’ profile was obtained for the cutin composition by GC-MS, with the cutin from tomato and apple peels being rich in polyhydroxy fatty acids whereas the cutin extracted from WP was mainly based on unsaturated fatty acids. All of the cutin samples showed an initial degradation temperature higher than 200 °C, presenting an excellent thermal stability. The strategy followed in this work has proved to be an effective valorization methodology with a high scaling-up potential for applications in the food, pharmaceutical, nutraceutical, cosmetics and biopolymer sectors

Desarrollo de metodologías innovadoras para la realización de actividades de laboratorio en la asignatura Análisis Toxicológico y Forense del Grado en Química

Se han diseñado estrategias innovadoras de enseñanza-aprendizaje para facilitar a los estudiantes la adquisición de competencias de Química Forense, particularmente la formulación de hipótesis para resolver casos prácticos. Con este propósito se han desarrollado actividades de laboratorio y metodologías colaborativas, creando una “escena de crimen” simulada a partir de la cual se proponen estrategias para su resolución. Los estudiantes deben formular una hipótesis de partida y analizar las evidencias obtenidas mediante el uso de diferentes técnicas analíticas. De esta forma se obtienen resultados que se ponen en común mostrando cada grupo sus principales conclusiones para formular una hipótesis final consensuada para la solución del caso. Como resultado de esta actividad se obtuvo una respuesta muy positiva de los estudiantes que aumentaron su motivación e interés por la parte práctica de la asignatura, al hacérseles más atractiva dejándoles la iniciativa para resolver un caso simulado. Se puede concluir que el trabajo colaborativo es reconocido por los estudiantes como una herramienta muy valiosa para adquirir las capacidades necesarias para su formación. Del mismo modo, se ha demostrado que tales capacidades y conocimientos pueden ser asimilados más fácilmente por los estudiantes utilizando herramientas interactivas y participativas para mejorar su rendimiento académico