Search

The growing number of older adults necessitates tailored food options that accommodate the specific diseases and nutritional deficiencies linked with ageing. This study aims to investigate the influence of age-related digestive conditions in vitro on the phenolic profile, antioxidant activity, and bioaccessibility of minerals (Ca, Fe, and Mg) in two types of unfermented, fermented, and fermented dried quinoa and lentils. Solid-state fermentation, combined with drying at 70 °C, significantly boosted the total phenolic content in Castellana and Pardina lentils from 5.05 and 6.6 to 10.5 and 7.5 mg gallic acid/g dry weight, respectively, in the bioaccessible fraction following the standard digestion model, compared to the unfermented samples. The phenolic profile post-digestion revealed elevated levels of vanillic and caffeic acids in Castellana lentils, and vanillic acid in Pardina lentils, while caffeic acids in Castellana lentils were not detected in the bioaccessible fraction. The highest antioxidant potency composite index was observed in digested fermented dried Castellana lentils, with white quinoa samples exhibiting potency above 80%. Mineral bioaccessibility was greater in fermented and fermented dried samples compared to unfermented ones. Finally, the digestive changes that occur with ageing did not significantly affect mineral bioaccessibility, but compromised the phenolic profile and antioxidant activity.

[ES] Las frutas y hortalizas son alimentos muy demandados actualmente gracias a los beneficios que poseen. Sin embargo, en estos productos el pardeamiento enzimático producido por la enzima polifenoloxidasa (PPO), conlleva un deterioro del color de estos, así como una pérdida de su valor nutricional lo que genera rechazo por parte del consumidor y en consecuencia grandes pérdidas económicas para la industria alimentaria. En el marco del presente estudio se ha analizado el efecto de la magnetización de materiales de sílice mesoporosos sin funcionalizar (M-UVM-7) y funcionalizados con aminas (UVM-7-NH2) y con tioles (UVM-7-SH) sobre el pardeamiento enzimático, así como sobre los compuestos bioactivos (polifenoles, flavonoides, flavonoles y capacidad antioxidante) presentes en el zumo de manzana. Por último, con el fin de reutilizar estos materiales se analizaron distintas estrategias de limpieza. En términos generales, se observó como el potencial fenólico del zumo de manzana se reducía siguiendo la misma tendencia que en presencia de la PPO para los tratamientos con M-UVM-7 y M-UVM-7-NH2. Sin embargo, el tratamiento con UVM-7-SH magnético preservó la estabilidad del color inicial del zumo de manzana medido a los 30 minutos de la retirada del material. Adicionalmente, la actividad antioxidante y el potencial fenólico presentaron escasas pérdidas (<20%). Finalmente, en cuanto a los sistemas de limpieza, destaca el mecanismo de agua acidificada debido a su capacidad de limpieza, su sencillez de aplicación y sus características económicas abriendo la posibilidad a la reutilización de los nanomateriales funcionalizados., [EN] Nowadays, fruits and vegetables are high demanded foods due to their health benefits. However, the enzymatic browning produced in these products by the polyphenol oxidase enzyme (PPO) entails a deterioration of their color as well as a loss of their nutritional value, which generates rejection by the consumer and consequently grand economic losses for food industry. This research studies the effect of magnetization of non-functionalized mesoporous silica materials (M-UVM-7) and functionalized with amines ((UVM-7-NH2) and with thiols (UVM-7-SH) on enzymatic browning, as well as on bioactive compounds (polyphenols, flavonoids, flavanols and antioxidant capacity) from apple juice. Finally, in order to reuse them, several cleaning strategies were studied. In general terms, it was observed how the phenolic potential of apple juice was reduced following the same trend as in the presence of PPO for M-UVM-7 and M-UVM-7-NH2 treatments. However, M-UVM-7-SH treatment preserved the beginning colour stability of apple juice measured 30 minutes after the removal of material. In addition, antioxidant activity and phenolic potential presented few degradation (<20%). Finally, regarding cleaning mechanisms, acidified water highlights due to its cleaning capacity, its simplicity of application and its economic characteristics, opening the possibility of reusing functionalized nanomaterials.

[EN] Aging is accompanied by changes in gastrointestinal functions. The impact of the gastrointestinal (GI) conditions of the elderly on the extent of proteolysis and glycolysis as well as calcium bioaccessibility in some cooked legumes (chickpea, lentils, soya bean and white bean) and cereals/pseudocereals (oats, spelt and quinoa) were studied. Samples were digested in vitro using three GI models specifically focused on the elderly in which oral, gastric and intestinal conditions were altered (E1: altered oral conditions, E2: altered oral and gastric conditions and E3: altered oral, gastric and intestinal conditions). Samples were also subjected to a standardized GI digestion as a control (C). The extent of proteolysis was only significantly affected with suboptimal intestinal conditions (p < 0.05). Protein digestibility of cereal grains decreased to a greater extent than for legumes. The release of non-essential amino acids was more affected than that of essential ones, mainly in legumes such as soya bean, lentils and white bean. The extent of glycolysis was much higher in cereal grains than legumes regardless of GI digestion conditions. Glycolysis declined with altered intestinal conditions (E3) compared to the C, in all legumes and spelt. Calcium bioaccessibility was much higher in cereal/pseudocereals than in legumes. However, calcium bioaccessibility seems to be highly limited in elderly people suffering from oral, gastric or intestinal alterations (up to 53% reduction compared to C). Such data might be helpful to develop dietary strategies based on protein-rich vegetal foods, including alternative crops such as oats, quinoa and spelt, specifically used to mitigate sarcopenia and osteoporosis in elderly people.

Tesis por compendio, [ES] El oscurecimiento de los tejidos de frutas y verduras dañados puede provocar cambios indeseables y el rechazo por parte del consumidor. Este deterioro, conocido como pardeamiento enzimático, es causado principalmente por la enzima polifenol oxidasa (PPO), que oxida los compuestos fenólicos en pigmentos rojizos llamados melanoides. De esta forma, la prevención de la actividad de PPO en el procesamiento postcosecha tanto en frutas y verduras como en sus licuados, ha recibido desde siempre mucha atención por parte de la industria alimentaria. Sin embargo, los tratamientos actuales presentan diversos inconvenientes, entre los que podemos destacar los efectos negativos en la calidad nutricional de los productos y su elevado coste. El cometido de esta tesis doctoral se centra en el desarrollo y evaluación de nuevas estrategias no térmicas para la inhibición de la PPO con el objetivo final de detener el pardeamiento enzimático. Para esto se abordaron dos estrategias diferentes. Por un lado, se seleccionaron y evaluaron varias poliaminas macrocíclicas. Se determinó que la estructura química influye fuertemente en el poder inhibidor, existiendo dos compuestos altamente eficaces contra el pardeamiento enzimático, los cuales presentan IC50 de 10 µM y 0.30 mM. Su eficacia se validó en zumo de manzana recién licuado retrasando el pardeamiento enzimático y la pérdida de compuestos fenólicos totales. Por otro lado, se estudió el desarrollo y aplicación de partículas de sílice mesoporosas funcionalizadas con diversos grupos químicos. Los resultados mostraron que tanto la estructura del material como la funcionalización son determinantes. El soporte UVM-7 ofreció la inhibición más fuerte sobre la enzima PPO, y una vez funcionalizado con grupos tiol este aumentó notablemente su poder inhibidor, deteniendo el pardeamiento enzimático en zumo de manzana. Por el contrario, los grupos amino, aunque mostraron menor poder inhibidor, fueron capaces de inmovilizar a la enzima y eliminarl, [CA] L'enfosquiment de fruïtes i verdures provoca un alt rebuig per part del consumidor. Aquest fet genera grans pèrdues econòmiques i un gran desaprofitament d'aliments. Aquest deteriorament, conegut com enfosquiment enzimàtic, és causat principalment per l'enzim polifenol oxidasa (PPO), que oxida els compostos fenòlics en pigments vermellosos anomenats melanoïdines. D'aquesta manera, la prevenció de l'activitat de la PPO en el processament postcollita tant en fruites i verdures com en els seus liquats, ha rebut des de sempre molta atenció per part de la indústria alimentària. No obstant això, els tractaments actuals presenten diversos inconvenients, entre els quals podem destacar els efectes negatius en la qualitat nutricional dels productes o el seu elevat cost. L'objectiu d'aquesta tesi doctoral es centra en el desenvolupament i avaluació de noves estratègies no tèrmiques per a la inhibició de la PPO amb la finalitat de detindre el enfosquiment enzimàtic. Per això s'aborden dues estratègies diferents. D'una banda, es va seleccionar i avaluar diverses poliamines macrocícliques. Determinat que l'estructura química influeix fortament en el poder inhibidor, existint dos compostos altament eficaços contra el enfosquiment enzimàtic, els quals presenten IC50 de 10 µM i 0.30 mM. La seua eficàcia es va validar en el suc de poma recentment liquat retardant el enfosquiment enzimàtic i la pèrdua de compostos fenòlics totals. D'altra banda, es va estudiat el desenvolupament i aplicació de partícules de sílice mesoporoses funcionalitzades amb diversos grups químics. Els resultats van mostrar que tant l'estructura del material com la funcionalització foren determinants. El suport UVM-7 va oferir la inhibició més forta sobre l'enzim PPO, i una vegada funcionalitzat amb grups tiol aquest va augmentar notablement el seu poder inhibidor, detenint el enfosquiment enzimàtic en el suc de poma. Tot i això, els grups amina, encara que mostren menys poder inhibidor, foren capaços d'immo, [EN] The browning of injured fruit and vegetable tissues can cause undesirable changes and consumers' rejection resulting in high economic losses and food waste. This damage, known as enzymatic browning, is mainly caused by the polyphenol oxidase enzyme (PPO) which oxidize the phenolic compounds found in these tissues into reddish pigments named melanonids. Thus, preventing PPO activity in post-harvest processing fruits and vegetables including their juices has received a lot of attention from the food industry. Nonetheless, the current alternatives have some drawbacks such as negative effects on the nutritional quality of products or high cost. Hence, the purpose of this doctoral thesis is focused on the development and evaluation of new non-thermal strategies for PPO inhibition and prevention of the enzymatic browning. For this purpose, two different strategies were addressed; On one hand, several macrocyclic polyamine compounds were selected and evaluated. The chemical structure was found to strongly influence the inhibitor power, and two different compounds were found to be efficient against the enzymatic browning with IC50 of 10 µM and 0.30 mM. Their effectiveness was proved in cloudy apple juice resulting in a delay of the enzymatic browning and the loss of total phenolic compounds. On the other hand, the development and application of mesoporous silica particles functionalized with diverse chemical groups were studied. The results showed that both the structure of the material and the type of functionalization are decisive. The UVM-7 support offered the strongest inhibition of the PPO. The functionalisation with thiol groups enhanced the inhibitor power stopping the enzymatic browning in cloudy apple juice. Alternatively, amine groups, although showing less inhibitory power, were able to immobilise the enzyme. Finally, the UVM-7 support was magnetized for easily elimination of the medium, thus preventing the juice filtration need. Cloudy apple juice treated w

This is the peer reviewed version of the following article: B. Díaz de Greñu, J. Torres, J. García-González, S. Muñoz-Pina, R. de los Reyes, A. M. Costero, P. Amorós, J. V. Ros-Lis, ChemSusChem 2021, 14, 208, which has been published in final form at https://doi.org/10.1002/cssc.202001865. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving., [EN] Covalent organic frameworks (COFs) are relatively recent materials. They have received great attention due to their interesting properties. However, the application of microwaves in their synthesis, despite its advantages such as faster and more reproducible processes, is a minority. Herein, a comprehensive compilation of the research results published in the microwave-assisted synthesis (MAS) of COFs is presented. This review includes articles of 2D and 3D COFs prepared using microwaves as source of energy. The articles have been classified depending on the functional groups including boronate ester, imines, enamines, azines, and triazines, among others. It compiles the main parameters of synthesis and characteristics of the materials together with some general issues related with COFs and microwaves. Additionally, current and future perspectives of the topic have been discussed.

This document is the unedited Author's version of a Submitted Work that was subsequently accepted for publication in Journal of Agricultural and Food Chemistry, copyright © American Chemical Society after peer review. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.jafc.0c02407, [EN] Enzymatic browning is one of the main problems faced by the food industry due to the enzyme polyphenol oxidase (PPO) provoking an undesirable color change in the presence of oxygen. Here, we report the evaluation of 10 different azamacrocyclic compounds with diverse morphologies as potential inhibitors against the activity of PPO, both in model and real systems. An initial screening of 10 ligands shows that all azamacrocyclic compounds inhibit to some extent the enzymatic browning, but the molecular structure plays a crucial role on the power of inhibition. Kinetic studies of the most active ligand (L2) reveal a S-parabolic I-parabolic noncompetitive inhibition mechanism and a remarkable inhibition at micromolar concentration (IC50 = 10 mu M). Furthermore, L2 action has been proven on apple juice to significantly reduce the enzymatic browning.

[EN] This study aimed to analyze the effect of elderly gastrointestinal (GI) conditions on proteolysis, lipolysis and calcium and vitamins A and D3 bioaccessibility in salmon, sardine, sea bass and hake. For this purpose, cooked fishes were in vitro subjected to three elderly in vitro digestion models: E1 (oral elderly conditions), E2 (oral and gastric elderly conditions) and E3 (oral, gastric and intestinal elderly conditions)). In parallel, samples were digested under standardized GI conditions of a healthy adult as a control. Proteolysis was highly affected by elderly GI alterations (p < 0.05) (50% of reduction compared to control), being salmon and sea bass proteolysis extent (40 and 33%, respectively) the most affected with an important descend in leucine release. Calcium and vitamins bioaccessibility seemed to be also compromised for elders; however, the extent of the reduction highly depends on the fish type. Finally, these GI disorders did not negatively influence the bioabsorbable lipids of the fishes

[EN] The effect of silica materials and their functionalization in the lipase catalyzed fat hydrolysis has been scarcely studied. Fifteen silica materials were prepared and their effect on the fat hydrolysis was measured, under simulated duodenal conditions, using the pH-stat method. The materials are composed of the combination of three supports (Stober massive silica nanoparticles, Stober mesoporous nanoparticles and UVM-7) and four surface functionalizations (methyl, trimethyl, propyl and octyl). In addition, the non-functionalized materials were tested. The functional groups were selected to offer a hydrophobic character to the material improving the interaction with the fat globules and the lipase. The materials are able to modulate the lipase activity and their effect depending on the support topology and the organic covering, being able to increase or reduce the fat hydrolysis. Depending of the material, relative fat hydrolysis rates of 75 to 140% in comparison with absence of the material were obtained. The results were analyzed by Partial Least Square Regression and suggest that the alkyl modified mesopores are able to improve the fat hydrolysis, by contrast the non-porous nanoparticles and the textural pores tend to induce inhibition. The effects are more pronounced for materials containing long alkyl chains and/or in absence of taurodeoxycholate.

[EN] This study aimed to evaluate the effect of some elderly in vitro gastrointestinal (GI) conditions on proteolysis and lipolysis extent, calcium, vitamins A and D bioaccessibility and lactose release in milk, yogurt, fresh and aged cheeses. To evaluate the impact of the some oral, gastric and intestinal disorders appearing with ageing on dairy digestion, three in-vitro elderly models were applied (E1 (oral altered conditions), E2 (oral and gastric altered conditions) and E3 (oral, gastric and intestinal altered conditions)) plus a healthy adult one as control. Proteolysis extent was significantly affected by elderly GI alterations (p < 0.05) (around 40% of reduction compared to control), being fresh and aged cheese proteolysis the most affected with an important descrease in leucine release (18 and 25%, respectively). Calcium, vitamins A and D3 bioaccesibility and lactose release seemed not to be highly compromised in these models of elderly conditions; however, the micronutrients bioaccessibility was very dependent on dairy matrix¿s structure. Finally, the amount of the lipid hydrolyzed fraction of cheeses is not influenced in the investigated models.

[ES] El envejecimiento es un proceso biológico que desencadena en una serie de cambios estructurales y funcionales, provocando alteración y deterioro a nivel del tracto digestivo, lo cual provoca maldigestión y malnutrición del adulto mayor por un déficit en la absorción de macro y micronutrientes. Debido a esto, el objetivo del presente estudio fue analizar, mediante el método de simulación in-vitro, la influencia de alteraciones fisiológicas a nivel oral, gástrico e intestinal que intervienen en la digestión de la población sénior (adulto > 65 años) sobre la digestibilidad de nutrientes presentes en productos lácteos. Se utilizaron técnicas de cromatografía de gases -espectrometría de masas (GC-MS), resonancia magnética nuclear (RMN-1H), colorimetría del Ácido Dinitrosalicílico (DNS) y espectrometría de absorción atómica de llama para determinar la influencia de las alteraciones antes mencionadas sobre la digestibilidad de proteínas, lípidos y glúcidos, así como la bioaccesibilidad de calcio en productos lácteos (leche entera, yogurt, queso curado y queso servilleta). Los resultados muestran, que las alteraciones de la fase oral, gástrica e intestinal conllevan una reducción de la hidrólisis proteica, dando lugar, por tanto, a un menor contenido de aminoácidos libres post-digestión. Particularmente, la leucina disminuye entre un 15 y 41.5% en los productos lácteos digeridos bajo condiciones gastrointestinales alteradas. La extensión de lipólisis, no se encuentra condicionada en condiciones gastrointestinales (GI) de individuos sénior, e incluso llegó a ser superior que en condiciones GI no alteradas. Este incremento, podría estar relacionado con la simulación de un mayor tiempo de residencia del alimento en la etapa intestinal bajo condiciones sénior (4 h frente a 2h en modelo no alterado). Por otro lado, la alteración intestinal podría ser responsable del descenso de la bioaccesibilidad de calcio registrado en el queso servilleta, aunque no en el resto de matrice, [EN] Aging is a biological process that triggers a series of structural and functional changes, causing alteration and deterioration at the level of the digestive tract, which causes maldigestion and malnutrition of the elderly due to a deficit in the absorption of macro and micronutrients. Due to this, the objective of the present study was to analyze, by means of the in-vitro simulation method, the influence of physiological alterations at the oral, gastric and intestinal level that intervene in the digestion of the senior population (adult> 65 years) on digestibility of nutrients present in dairy products. Gas chromatography-mass spectrometry (GC-MS), nuclear magnetic resonance (NMR-1H), Dinitrosalicylic Acid (DNS) colorimetry and flame atomic absorption spectrometry were used to determine the influence of the aforementioned alterations on the digestibility of proteins, lipids and carbohydrates, as well as the bioavailability of calcium in dairy products (whole milk, yogurt, cured cheese and napkin fresh cheese). The results show that alterations of the oral, gastric and intestinal phase lead to a reduction in protein hydrolysis, resulting, therefore, in a lower content of free amino acids post-digestion. Particularly, leucine decreases between 15 and 41.5% in digested dairy products under altered gastrointestinal conditions. The extent of lipolysis, is not conditioned in gastrointestinal (GI) conditions of senior individuals, and even became higher than in unaltered GI conditions. This increase could be related to the simulation of a longer residence time of the food in the intestinal stage under senior conditions (4 hours versus 2 hours in an unaltered model). On the other hand, the intestinal alteration could be responsible for the decrease in the bioaccessibility of calcium registered in the napkin fresh cheese, although not in the rest of the matrices. Finally, gastrointestinal disorders have a statistically significant effect on the release of sugars in coa, [CA] L'envelliment és un procés biològic que desencadena en una sèrie de canvis estructurals i funcionals, provocant alteració i deteriorament a nivell del tracte digestiu, la qual cosa provoca maldigestió i malnutrició de l'adult major per un dèficit en l'absorció de macro i micronutrients. A causa d'això, l'objectiu d'aquest estudi va ser analitzar, mitjançant el mètode de simulació in-vitro, la influència d'alteracions fisiològiques a nivell oral, gàstric i intestinal que intervenen en la digestió de la població sènior (adult> 65 anys) sobre la digestibilitat de nutrients presents en productes lactis. Es van utilitzar tècniques de cromatografia de gasos -espectrometría de masses (GC-MS), ressonància magnètica nuclear (RMN-1H), colorimetria de l'Àcid Dinitrosalicílico (DNS) i espectrometria d'absorció atòmica de flama per 3 determinar la influència de les alteracions abans esmentades sobre la digestibilitat de proteïnes, lípids i glúcids, així com la bioaccesibilitat de calci en productes lactis (llet sencera, iogurt, formatge curat i formatge tovalló). Els resultats mostren, que les alteracions de la fase oral, gàstrica i intestinal comporten una reducció de la hidròlisi proteica, donant lloc, per tant, a un menor contingut d'aminoàcids lliures post-digestió. Particularment, la leucina disminueix entre un 15 i 41.5% en els productes lactis digerits sota condicions gastrointestinals alterades. L'extensió de lipòlisi, no es troba condicionada en condicions gastrointestinals (GI) d'individus sènior, i fins i tot va arribar a ser superior que en condicions GI no alterades. Aquest increment, podria estar relacionat amb la simulació d'un major temps de residència de l'aliment en l'etapa intestinal sota condicions sènior (4 h davant de 2h a model no alterat). D'altra banda, l'alteració intestinal podria ser responsable del descens de la bioaccesibilitat de calci registrat en el formatge tovalló, encara que no en la resta de matrius. Finalment, les alteracions gastrointe

[EN] Darkening processed fruits and vegetables is caused mainly by enzymatic browning through polyphenol oxidase (PPO) action. Accordingly, we explored the potential of four silica-based materials (MCM-41 nanometric size, MCM-41 micrometric size, UVM-7 and aerosil), non-functionalised and functionalised with thiol groups, to inhibit PPO activity in the model system and apple juice. All materials showed relevant performance when immobilising and inhibiting PPO in model systems, and support topology is a main factor for enzyme immobilisation and inhibition. Thiol-containing silica UVM7-SH showed the greatest inactivation, and similar browning values to those obtained by acidification. The enzyme's kinetic parameters in the presence of UVM-7-SH suggested non-competitive inhibition, which indicated that the material interacted with the enzyme, but beyond the active centre. In real systems, UVM-7-SH completely inhibited enzymatic browning in apple juice (cv. Granny Smith and cv. Golden Delicious) up to 9 days after 5 min of contact.

[ES] La apariencia de un alimento es el primer factor que condiciona al consumidor a la hora de escoger un producto. El oscurecimiento en frutas y verduras cortadas se debe fundamentalmente al pardeamiento enzimático, el cual se produce por la acción de la enzima polifenol oxidasa (PPO). En el marco del presente estudio se ha profundizado en el potencial de un material mesoporoso de sílice, sin funcionalizar (UVM-7) y funcionalizado con tioles (UVM-7-SH), para la inhibición de la tirosinasa, tanto en sistemas modelo como en zumos de manzana. En el presente trabajo se presentan los resultados de caracterización del material, los resultados de los ensayos de cinética enzimática de la tirosinasa frente a distintos sustratos y condiciones de pH en sistemas modelo, y finalmente, los resultados de las pruebas de aplicación en zumos de manzana. Los resultados confirman que en presencia de material UVM-7-SH la actividad enzimática se reduce notablemente hasta valores similares a los obtenidos mediante procesos de acidificación. Por otro lado se observa que la actividad enzimática residual depende la cantidad de material presente en el medio, y se ha estimado que el ratio material:enzima capaz de inhibir a la enzima por completo en los sistemas modelo es de 3 mg por 93,75U. En cuanto a los sistemas reales, se observó que el material UVM- 7-SH consigue inhibir por completo el pardeamiento enzimático en zumos de manzana (cv. Granny Smith y cv. Golden Delicious)., [EN] Food appearance is the first factor consumers consider when choosing a product. Darkening in cut fruits and vegetables is mainly due to enzymatic browning, produced by the action of PPO. This research study the potential of the silica material UVM-7 and its equivalent functionalized with thiol groups (UVM-7-SH), to inhibit the tyrosinase both in model system and apple juice. This paper shows the results of material characterization, the results of enzyme kinetic assays with different substrates, and finally, the results of the test on apple juices. Results confirm that in presence of the silica material UVM-7-SH, enzymatic activity is notably reduced until it reaches similar values to the ones obtained by acidification processes. Furthermore, it is observed that the residual enzyme activity depends on the amount of material present in the medium, and it has been estimated that the material-enzyme ratio capable of completely inhibit the enzyme in model systems is 3mg per 93,75U. Regarding real systems, it was observed that UVM-7-SH material completely inhibits enzymatic browning in apple juices (cv. Granny Smith y cv. Golden Delicious)., [CA] L'aparença d'un aliment és el primer factor que condiciona al consumidor a l'hora d'escollir un producte. L’enfosquiment en fruites i verdures tallades es deu a l'enfosquiment enzimàtic, el qual es produeix per l'acció del enzim polifenol oxidasa (PPO). Al marc del present estudi s'ha aprofundit en la potencial d’un material mesoporós de sílice, sense funcionalizar (UVM-7) i funcionalitzats amb tiols (UVM-7-SM), per a la inhibició de la tirosinasa, tant en sistemes model com en sucs de poma. En el present treball es presenten els resultats de la caracterització del material, els resultats dels assajos de cinètica enzimàtica de la tirosinasa enfront de diferents substrats i diferents condicions de pH en sistemes model, i finalment, els resultats de les proves d’aplicació en sucs de poma. Els resultats confirmen que en presencia de material UVM-7-SH l'activitat enzimàtica es redueix notablement fins a valors similars als obtinguts mitjançant processos d’acidificació. Per altra banda, s'observa que l’activitat enzimàtica residual depèn de la quantitat de material present en el medi, i s’ha estimat que el ràtio material: enzim capaç d’inhibir a l’enzim completament en els sistemes model és de 3mg per 93,75U. Respecte als sistemes reals, es va observar que el material UVM-7-SH aconsegueix inhibir per complet l'enfosquiment enzimàtic en sucs de poma (cv. Granny Smith y cv. Golden Delicious).