Antonio Diego Rodríguez López

This study focused on the clarification of real blanching wastewaters from the industrial processing of cardoon, a plant rich in polyphenols and belonging to the artichoke family (Cynara cardunculus). The aim of this study was to evaluate the performance of ultrafiltration (UF) as an initial clarification step prior to a subsequent nanofiltration treatment for the recovery and fractionation of polyphenols from these wastewaters. In this UF process, three commercial UF membranes with different pore sizes: 3 kDa, 15 kDa, and 50 kDa. The assessment of the clarification process was based on two key factors: permeate flux and the concentration of phenolic compounds. The membrane with a MWCO of 3 kDa was excluded as a potential UF membrane due to its limited performance in terms of permeate flux. The 15 kDa membrane showed comparable results in terms of cumulative flux to the 50 kDa membrane. However, further evaluation based on fouling index and water permeability recovery favored the 15 kDa membrane, indicating better performance. To gain insights into the flux decline mechanisms and understand membrane fouling, a study was conducted on the 15 kDa and 50 kDa membranes. The analysis revealed that the cake filtration model provided the best fit for both membranes. The study highlights the potential of UF membranes, specifically the 15 kDa membrane, for the clarification of cardoon blanching wastewater.

Integración de las nuevas competencias transversales UPV y la formación en ODS en las actividades prácticas de una asignatura del MUII

Artichoke wastes after processing represent 60–70% of the raw material and are a potential source of inulin and polyphenols, bioactive compounds that can be valorized as food ingredients or nutraceutical products. The aim of this work was to assess and optimize the extraction of these compounds from artichoke wastes using water or water–ethanol mixtures as extracting agents. For simultaneous inulin and polyphenol extraction and to achieve high antioxidant activity in extracts, the best process conditions using water as an extracting agent were T = 89 °C and t = 139 min, where 80% of the inulin content, 60% of the total phenolic content (TPC) and 56% of the antioxidant activity (Aox) were obtained. For water–ethanol extractions, the best results were obtained with EtOH = 22.4%, T = 81 °C and t = 217 min, leading to extraction yields of 90% of TPC, 38% of Aox and 58% of inulin content. From these results, we recommend the use of water for the recovery of inulin and polyphenols from artichoke wastes. Although the extraction yield of polyphenols is lower in water treatments, the amount extracted is considerable and it is a greener option when compared with water–ethanol mixtures.

Consumers are becoming more conscious about the need to include functional and nutritional foods in their diet. This has increased the demand for food extracts rich in proteins and peptides with physiological effects that are used within the food and pharmaceutical industries. Among these protein extracts, soy protein and its derivatives are highlighted. Isolated soy protein (ISP) presents a protein content of at least 90%. Wastewaters generated during the production process contain small proteins (8–50 kDa), and it would be desirable to find a recovery treatment for these compounds. Ultrafiltration membranes (UF) are used for the fractionation and concentration of protein solutions. By the appropriate selection of the membrane pore size, larger soy proteins are retained and concentrated while carbohydrates and minerals are mostly recovered in the permeate. The accumulation and concentration of macromolecules in the proximity of the membrane surface generates one of the most important limitations inherent to the membrane technologies. In this work, three UF membranes based on polyethersulfone (PES) were fabricated. In two of them, polyethylene glycol (PEG) was added in their formulation to be used as a fouling prevention. The membrane fouling was evaluated by the study of flux decline models based on Hermia’s mechanisms.

Food wastes have traditionally been considered as dead-end materials; however, recent international, national, and regional policies strongly promote the use of these wastes as potential resources. This change of perception considers the need for sustainable exploitation of natural resources. In this context, artichoke processing produces high amounts of wastewaters, and specifically, wastewaters from the artichoke blanching step present a high content of valuable biocomponents such as carbohydrates and phenolic compounds (e.g., chlorogenic acid, 1700 ppm). In this work, the recovery of chlorogenic acid by applying sorption processes was studied. Five resins were tested, and it was found that the resin XAD 7 HP presented the best total adsorption-desorption yield (72.8%) at 20 °C. It was also found that there was a strong variation of the adsorption ratio depending on solution pH (3–7). Four models of isotherms were applied to the adsorption processes, and the Langmuir isotherm better explained the adsorption behavior. The kinetic study showed that the adsorption and desorption of chlorogenic acid followed a pseudo-second order model where the kinetic constant depended on the adsorbate concentration. In addition, it was found that the sorption process was controlled by more than just the intraparticle diffusion mechanism.

Aplicación del Aprendizaje Basado en Problemas (ABP) en una asignatura del Máster Universitario de Ingeniería Industrial: propuesta metodológica y de evaluación

Ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) of bioactive compounds, peels from Opuntia engelmannii cultivar (cv.) Valencia were optimized by response surface methodology. Randomized extraction runs were performed for each of the technologies employed in order to build effective models with maximum (bioactive molecules content and yield) and minimum (antioxidant activity) responses. A 5-level, 4-factor central composite design was used to obtain target responses as a function of extraction time (t), solid to liquid ratio (S/L), methanol concentration (metOH), and temperature (T). Specific response optimization for each technology was analyzed, discussed, and general optimization from all the responses together was also gather. The optimum values for each factor were: t = 2.5 and 1.4 min, S/L = 5 and 5 g/L, metOH = 34.6 and 0% of methanol and T = 30 and 36.6 °C, achieving maximum responses of 201.6 and 132.9 mg of betalains/g, 13.9 and 8.0 mg of phenolic acids/g, 2.4 and 1.5 mg of flavonoids/g, 71.8% and 79.1% of extractable solid and IC₅₀ values for the antioxidant activity of 2.9 and 3.6, for UAE and MAE, respectively. The present study suggested UAE as the best extraction system, in order to maximize recovery of bioactive compounds with a high antioxidant activity.