Development of magnetic carbon xerogels for catalytic wet peroxide oxidation

Hybrid magnetic carbon composites have been recently proposed as the next step in the evolution of catalysts for catalytic wet peroxide oxidation (CWPO), with several synergistic effects arising from the combination of the high catalytic activity of metal species with the proven catalytic properties of carbon-based materials in CWPO [1]. Bearing this in mind, this work sought the development of novel magnetic carbon xerogels, composed by interconnected carbon microspheres with iron (Fe) and/or cobalt (Co) microparticles embedded in their structure. As inferred from the extensive characterization performed, materials with distinctive properties were obtained upon inclusion of different metal precursors during the sol-gel polymerization of resorcinol and formaldehyde, followed by thermal annealing.

Obtenção de extratos de agaricus bisporus com ergosterol para incorporação em iogurtes e procedimentos de microencapsulação

Além de ser o cogumelo mais consumido no mundo, Agaricus bisporus é um dos cogumelos mais ricos em ergosterol, representando esta molécula quase 90% da sua fração de esteróis. Vários estudos têm atribuído ao ergosterol diferentes bioatividades, incluindo efeitos hipocolesterolémicos semelhantes aos exibidos pelos fitoesteróis. Isto torna o ergosterol uma molécula interessante para ser estudada como composto nutracêutico. Assim, este trabalho teve como objetivo avaliar o potencial de utilização dos extratos de A. bisporus ricos em ergosterol na produção de bebidas lácteas funcionais. Para o efeito, foram realizados testes de incorporação do extrato e do ergosterol puro em iogurtes que se compararam com bebidas lácteas funcionais comerciais (aditivadas com fitoesteróis). As amostras de A. bisporus foram submetidas a uma extração assistida por ultrassons e os extratos obtidos (IEXT), bem como a molécula de ergosterol em diferentes concentrações (IERG1 e IERG2), foram incorporados em iogurtes, e comparadas com amostras controlo (amostras de iogurte sem aditivos) (ICN) e iogurtes comerciais contendo fitoesteróis (ICP). Todas as amostras foram analisadas imediatamente após a incorporação (T0), e após sete dias de armazenagem a 4°C (T1), em relação aos parâmetros nutricionais, atividade antioxidante e propriedades citotóxicas em linhas celulares tumorais humanas e numa cultura primária de células de fígado de porco (não tumoral) para avaliação da toxicidade. O teor de ergosterol incorporado na forma pura, ou presente nos extratos, foi monitorizado por HPLC-UV. Adicionalmente, foi realizado um estudo de microencapsulação utilizando a técnica de coacervação, tendo o quitosano e o isolado proteico de soro como materiais encapsulantes. Num ensaio preliminar determinou-se o pH conducente a um maior rendimento de encapsulação e, seguidamente, verificou-se a influência da razão proteína:quitosano (P/Q) e da temperatura utilizada, no rendimento de encapsulação (Y1), na eficiência de encapsulação (Y2) e na carga (teor de ergosterol nas microesferas) (Y3). Posteriormente, o estudo foi realizado baseando-se nas melhores condições para encapsular ergosterol, sendo também avaliadas as respostas Y1, Y2 e Y3. Além de ser o cogumelo mais consumido no mundo, Agaricus bisporus é um dos cogumelos mais ricos em ergosterol, representando esta molécula quase 90% da sua fração de esteróis. Vários estudos têm atribuído ao ergosterol diferentes bioatividades, incluindo efeitos hipocolesterolémicos semelhantes aos exibidos pelos fitoesteróis. Isto torna o ergosterol uma molécula interessante para ser estudada como composto nutracêutico. Assim, este trabalho teve como objetivo avaliar o potencial de utilização dos extratos de A. bisporus ricos em ergosterol na produção de bebidas lácteas funcionais. Para o efeito, foram realizados testes de incorporação do extrato e do ergosterol puro em iogurtes que se compararam com bebidas lácteas funcionais comerciais (aditivadas com fitoesteróis). As amostras de A. bisporus foram submetidas a uma extração assistida por ultrassons e os extratos obtidos (IEXT), bem como a molécula de ergosterol em diferentes concentrações (IERG1 e IERG2), foram incorporados em iogurtes, e comparadas com amostras controlo (amostras de iogurte sem aditivos) (ICN) e iogurtes comerciais contendo fitoesteróis (ICP). Todas as amostras foram analisadas imediatamente após a incorporação (T0), e após sete dias de armazenagem a 4°C (T1), em relação aos parâmetros nutricionais, atividade antioxidante e propriedades citotóxicas em linhas celulares tumorais humanas e numa cultura primária de células de fígado de porco (não tumoral) para avaliação da toxicidade. O teor de ergosterol incorporado na forma pura, ou presente nos extratos, foi monitorizado por HPLC-UV. Adicionalmente, foi realizado um estudo de microencapsulação utilizando a técnica de coacervação, tendo o quitosano e o isolado proteico de soro como materiais encapsulantes. Num ensaio preliminar determinou-se o pH conducente a um maior rendimento de encapsulação e, seguidamente, verificou-se a influência da razão proteína:quitosano (P/Q) e da temperatura utilizada, no rendimento de encapsulação (Y1), na eficiência de encapsulação (Y2) e na carga (teor de ergosterol nas microesferas) (Y3). Posteriormente, o estudo foi realizado baseando-se nas melhores condições para encapsular ergosterol, sendo também avaliadas as respostas Y1, Y2 e Y3. As bebidas funcionalizadas com o extrato (IEXT) e com ergosterol na mesma concentração existente no extrato (IERG1) revelaram uma atividade antioxidante similar às bebidas comerciais com fitoesteróis. No entanto, as bebidas com ergosterol na mesma concentração do extrato de A. bisporus e de fitoesteróis (IERG2) revelaram uma atividade antioxidante superior. Além disso, apenas IEXT, IERG1 e IERG2 apresentaram um aumento na atividade antioxidante de T0 para T1, com destaque para a atividade exibida por IERG2, significando que o ergosterol e os extratos foram capazes de proteger a bebida láctea da oxidação, aumentando a vida de prateleira do produto. IERG2 foi a amostra que revelou a maior citotoxicidade para as linhas celulares tumorais, enquanto as bebidas com fitoesteróis mostraram a menor atividade, sem diferenças significativas entre T0 e T1. Os estudos de microencapsulação revelaram ainda que a técnica de coacervação permite obter cápsulas de distintos tamanhos e que as condições ótimas do processo ocorrem a pH 5,5, com temperatura de 55ºC e razão P/Q de 0,5, com um menor rendimento de encapsulação, mas com uma maior carga em ergosterol. Este trabalho contribuiu para o estudo do potencial da utilização de extratos de A. bisporus com ergosterol no desenvolvimento de novas bebidas funcionais. Constituiu um primeiro passo que necessita de estudos subsequentes relacionados com a avaliação da viabilidade da sua utilização ao nível industrial e demonstração clara da sua bioatividade in vivo.

Magnetic carbon xerogels for the catalytic wet peroxide oxidation of sulfamethoxazole in environmentally relevant water matrices

Novel magnetic carbon xerogels consisting of interconnected carbon microspheres with iron and/or cobalt microparticles embedded in their structure were developed by a simple route. As inferred from the characterization data, materials with distinctive properties may be directly obtained upon inclusion of iron and/or cobalt precursors during the sol-gel polymerization of resorcinol and formaldehyde, followed by thermal annealing. The unique properties of these magnetic carbon xerogels were explored in the catalytic wet peroxide oxidation (CWPO) of an antimicrobial agent typically found throughout the urban water cycle – sulfamethoxazole (SMX). A clear synergistic effect arises from the inclusion of cobalt and iron in carbon xerogels (CX/CoFe),the resulting magnetic material revealing a better performance in the CWPO of SMX at the ppb level(500 microg L−1) when compared to that of monometallic carbon xerogels containing only iron or cobalt.This effect was ascribed to the increased accessibility of highly active iron species promoted by the simultaneous incorporation of cobalt.The performance of the CWPO process in the presence of CX/CoFe was also evaluated in environmentally relevant water matrices, namely in drinking water and secondary treated wastewater, considered in addition to ultrapure water. It was found that the performance decreases when applied to more complex water and wastewater samples. Nevertheless, the ability of the CWPO technology for the elimination of SMX in secondary treated wastewater was unequivocally shown, with 96.8% of its initial content being removed after 6 h of reaction in the presence of CX/CoFe, at atmospheric pressure, room temperature(T = 25◦C), pH = 3, [H2O2]0= 500 mg L−1and catalyst load = 80 mg L−1. A similar performance (97.8% SMX removal) is obtained in 30 min when the reaction temperature is slightly increased up to 60◦C in an ultra-pure water matrix. Synthetic water containing humic acid, bicarbonate, sulphate or chloride, was also tested. The results suggest the scavenging effect of the different anions considered, as well as the negative impact of dissolved organic matter typically found in secondary treated wastewater, as simulated by the presence of humic acid.An in-situ magnetic separation procedure was applied for catalyst recovery and re-use during reusability cycles performed to mimic real-scale applications. CWPO runs performed with increased SMX concentration (10 mg L−1), under a water treatment process intensification approach, allowed to evalu-ate the mineralization levels obtained, the antimicrobial activity of the treated water, and to propose adegradation mechanism for the CWPO of SMX.

Utilization of free and microencapsulated Rosmarinus oficinalis L. extracts as bioactives ingredientes for new functional foods developmen

Currently, many consumers search for food with functional characteristics beyond their nutritional properties. Thus, the concept of functional food becomes a hot topic, allowing the obtaining of health benefits, including disease prevention. In this context, plants are recognized as sources of a wide range of bioactives, mainly phenolic compounds. In particular, the Rosmarinus officina/is L., commonly referred as rosemary, has several phenolic compounds with different bioactive properties such as antioxidant, antiinflammatory and antimicrobial activities, among others [!]. Hence, this plant has great potential for incorporation into foods in order to confer bioactivity to the final products. However, it should be highlighted that the bioactive compounds if exposed to adverse environments, for example: light, moisture, extreme pH, storage, food processing conditions, can be degraded leading to the consequent loss of bioactivity [2]. The microencapsulation is an alternative to overcome this problematic of bioactive compounds, as also to ensure controlled release, or target deliver to a specific site [3]. In this work, lyophilized rosemary aqueous extract prepared by in:'usion was used as a functional ingredient for cottage cheeses, after proving that it possesses, both higher content in phenolic compounds and higher antioxidant activity, comparatively with the corresponding hydroethanolic extract. The rosemary aqueous extract revealed, for example, a DPPH scavenging activity with an EC50 value of 73.44±0.54j!g/mL and presented as main phenolic compound the caffeic acid dimer, commonly named as rosmarinic acid. For the functionalized cottage cheeses, a decrease of bioactivity was observed after seven days under storage in fridge, when the extracts were incorporated in its free form. Therefore, to preserve the antioxidant activity, the rosemary aqueous extract was efficiently microencapsulated by using an atomization/coagulation technique and alginate as the matrix material and thereafter incorporated into the cottage cheeses. The final microspheres showed a size, estimated by OM using a magnification of I OOx, ranging between 51.1 and 122.6 J!m and an encapsulation efficiency, estimated through an indirect method, approaching 100%. Overall, the introduction of both free and microencapsulated extracts did not change the nutritional value of cottage cheeses, providing bioactivity that was more preserved with microencapsulated extracts putting in evidence the importance of using microencapsulation to develop effective functional foods.

Antiangiogenic potential of yogurts added with extracts rich in apigenin derivatives

Angiogenesis is a biological process through which there is the formation of new blood vessels from preexisting ones [I]. However, in pathological cases, the abnormal growth of new blood vessels promotes the development of various diseases including cancer [2) through the production of atypically large amounts of angiogenesis factors, e.g. the vascular endothelial growth factor (VEGF) [3]. The plant secondary metabolites have been the subject of several studies to evaluate their benefits to human health. In particular, the phenolic compounds have high potential for use in the food industry, including the development of functional foods. Among these, apigenin has been associated with chemopreventive effects related to cancer [4]. In fact, chemoprevention is a present-day concept and contemplates the use of medicines, biological compounds or nutrients as an intervention strategy of cancer prevention. In this work, an Arenaria montana L hydroethanolic extract was prepared and after characterization by HPLC-DAD-ESI/MS showed to be rich in apigenin derivatives. Furthermore, it exhibited ability to inhibit the phosphorylation of VEGFR-2 (vascular endothelium growth factor receptor) through an enzymatic assay. However, for the major protection of bioactive compounds, the extract was microencapsulated by an atomization/coagulation technique with alginate as the matrix material. Posteriorly, the hydroethanolic extract, in free and microencapsulated forms, was incorporated in yogurts in order to develop a novel chemopreventer food in relation to the angiogenesis process. The functionalized yogurts with A. montana extracts (free and microencapsulated) showed a nutritional value similar to the used control (yogurt without extract); however, the samples enriched with extracts revealed added-value regarding the VEGFR-2 phosphorylation inhibition ability. This effect was more effectively preserved over time in the samples functionalized with the protected extract. Overall, this work contributes to the valorization of plants rich in flavonoids, exploring its antiangiogenic potential with VEGFR-2 as target. Moreover, the atomization/coagulation technique allowed the production of viable microspheres enriched with the plant extract. The microspheres were effectively incorporated into yogurts, protecting the extract thus envisaging the development of novel functional foods with chemopreventive effects.

Micoencapsulation of bioactive plant extracts: a tool to functionalize cottage cheeses

Foeniculum vulgare Mill. (fennel) and Matricaria recutita L. (chamomile) are two examples of plants with reported antioxidant and antimicrobial properties, which can be related with their composition in phenolic compounds [1,2]. Furthermore, according to previous results of our research group, the direct incorporation of the aqueous extracts showed capacity to maintain the nutritional properties of the cottage cheeses, up to 7 days of storage, while improving the antioxidant potential. However, after 14 days, a decrease in the antioxidant properties was observed [1,2], which can be related with factors such as light, moisture, temperature and pH, that can cause bioactive compounds degradation. Therefore, the aim of the present study was to prepare microcapsules with the aqueous extracts of fennel and chamomile for incorporation in cottage cheese samples, in order to protect the bioactive molecules present in the extracts, such as phenolic compounds, and prevent the decrease of the antioxidant activity observed after the 14 days period. The microspheres were prepared using an atomization/coagulation technique. Sodium alginate was used as the matrix material to produce the microspheres that were characterized through optical microscopy (OM), during and after atomization, for inspecting morphology. The encapsulation efficiency (EE) was determined by HPLC-DAD by an indirect method by analysing the coagulation solution. FTIR was also used to attest the presence of the extract inside of the alginate matrix. These microencapsulated extracts were incorporated in cottage cheese samples that were further characterized in terms of nutritional properties and antioxidant potential right after incorporation, and after 7 and 14 days of storage at 4•c. The EE was estimated as -100% and the FTIR analysis confirmed the presence of the extracts inside the microspheres. The results showed that the incorporation of the microencapsulated extracts did not cause changes in the nutritional value of cottage cheeses (through a comparison with control samples without extracts). The predominant fatty acids were palmitic (C16:0) and oleic (CI8:0) acids. The order of abundance of fatty acids was as follows: saturated fatty acids (SF A)> monounsaturatcd fatty acids (MUF A)> polyunsaturated fatty acids (PUF A). Regarding free sugars, lactose was the only sugar identified and quantified in all samples. Regarding the antioxidant activity, the samples functionalized with the microencapsulated extracts showed a higher preservation of this property even after the 7th day of storage. Overall, the incorporation of the protected plant extracts in dairy foods can be a strategy to provide health benefits to consumers.

Ceratonia siliqua L. hydroethanolic extract obtained by ultrasonication: antioxidant activity, phenolic compounds profile and effects in yogurts functionalized with their free and microencapsulated forms

Bioactive extracts were obtained from powdered carob pulp through an ultrasound extraction process and then evaluated in terms of antioxidant activity. Ten minutes of ultrasonication at 375 Hz were the optimal conditions leading to an extract with the highest antioxidant effects. After its chemical characterization, which revealed the preponderance of gallotannins, the extract (free and microencapsulated) was incorporated in yogurts. The microspheres were prepared using an extract/sodium alginate ratio of 100/400 (mg mg(-1)) selected after testing different ratios. The yogurts with the free extract exhibited higher antioxidant activity than the samples added with the encapsulated extracts, showing the preserving role of alginate as a coating material. None of the forms significantly altered the yogurt's nutritional value. This study confirmed the efficiency of microencapsulation to stabilize functional ingredients in food matrices maintaining almost the structural integrity of polyphenols extracted from carob pulp and furthermore improving the antioxidant potency of the final product.