Percorrer por autor "Fernandes, Pedro"

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    Assessing the potential of brewer’s spent grain to enhance cookie physicochemical and nutritional profiles
    (Multidisciplinary Digital Publishing Institute (MDPI), 2025-01-02) Nicolai, Marisa; Palma, Maria Lídia; Reis, Ricardo; Amaro, Rúben; Fernandes, Jaime; Gonçalves, Elsa M.; Silva, Mafalda; Lageiro, Manuela; Charmier, Adília; Maurício, Elisabete; Branco, Patrícia; Palma, Carla; Silva, Joaquim; Nunes, Maria Cristiana; Fernandes, Pedro; Pereira, Paula; CBIOS - Research Center for Biosciences & Health Technologies; BioRG - Bioengineering & Sustainability Research Group; EPCV - School of Psychology and Life Sciences
    Brewers’ spent grain (BSG), the major by-product of the brewery industry, has high nutritional value, making it suitable for upcycling into products such as healthy, and sustainable cookies. Nonetheless, the incorporation of BSG in cookies can impact their quality, given the increased fiber and protein content. This work explored the effect of replacing wheat flour with BSG at 50% and 75% in cookie formulations, focusing on physical, chemical, and sensory properties. The dietary fiber, lipid, and protein content of cookies improved considerably with the highest incorporation of BSG, increasing from 6.37% to 15.54%, 9.95% to 13.06%, and 9.59% to 12.29%, respectively. Conversely, moisture and water activity decreased from 11.03% to 3.37% and 0.742 to 0.506, respectively, forecasting a lower risk of microbial contamination and increased shelf-life. The incorporation of BSG in cookies resulted in decreased brightness and increased hardness, from 40 N to 97 N. Moreover, colorimetric shifts among the control cookies and the two BSG-rich formulations could be easily identified by an untrained observer. Sensory evaluation showed that cookies with 50% BSG retained acceptable sensory characteristics, suggesting potential for further development. Overall, BSG enhances the nutritional profile of cookies with no excessive detrimental impact on sensory features.
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    Improvement of aglycone content in soy isoflavones extract by free and immobilized β-Glucosidase and their effects in lipid accumulation
    (Springer, 2020-11-01) Angelotti, Joelise A.F.; Dias, Fernanda F.G.; Sato, Hélia H.; Fernandes, Pedro; Nakajima, Vânia M.; Macedo, Juliana; FE - Faculty of Engineering
    Soybean is one of the most important commodities in the world, being applied in feed crops and food, pharmaceutical industries in different ways. Soy is rich in isoflavones that in aglycone forms have exhibited significant anti-obesity and anti-lipogenic effects. Obesity is a global problem as several diseases have been related to this worldwide epidemic. The aim of this work was to verify the effect of free and immobilized β-glucosidase, testing Lentikats, and sol–gel as carriers. Moreover, we wanted to examine if the different types of hydrolysis would generate extracts with distinct biological activity concerning lipid accumulation, PPAR-α regulation, and TNF-α, IL-6, and IL-10 concentrations using in vitro assays. Our results show that all formulations of β-glucosidase could hydrolyze soy isoflavones. Thus, after 24 h of incubation, daidzein content increased 2.6-, 10.8-, and 12.2-fold; and genistein content increased 11.7, 11.4, and 11.4 times with the use of free enzyme, Lentikats®, and sol–gel immobilized enzyme, respectively. Moreover, both methodologies for enzyme immobilization led to promising forms of biocatalysts for application in the production of soy extracts rich in isoflavones aglycones, which are expected to bring about health benefits. A mild lipogenic effect was observed for some concentrations of extracts, as well as a slight inhibition in PPAR-α expression, although no significant differences were noticeable in the cytokines TNF-α, IL-10, and IL-6 as compared with the control.
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    Inulinase from Rhodotorula mucilaginosa : immobilization and application in the production of fructooligosaccharides
    (The Korean Society of Food Science and Technology, 2021-07) de Araujo Ribeiro, Geise Camila; Fernandes, Pedro; Silva, Dayse Alessandra Almeida; Brandão, Hugo Neves; de Assis, Sandra Aparecida; FE - Faculty of Engineering
    The crude extract containing inulinase from Rhodotorula mucilaginosa was obtained by submerged fermentation. Inulinase was immobilized on chicken eggshell by physical adsorption and covalent crosslinking, using glutaraldehyde as a crosslinking reagent, and Celite by adsorption. Fructooligosaccharides production was performed using immobilized inulinase (5%, w/v) and inulin substrate solution under experimental conditions evaluated through Doehlert experimental design. The production of inulinase was optimized for concentrations of D-glucose and yeast extract at 12.5 and 0.5 g/L, respectively, resulting in an optimal activity of 0.62 U. The optimal pH and temperature for enzyme activity were 8.0 and 75 °C, respectively, leading to an optimal activity of 3.54 U. The highest immobilization efficiency (46.27%) was obtained upon immobilization on Celite. Immobilization by adsorption to eggshell allowed for specific activity of 4.15 U/g, and adsorption to Celite resulted in specific activity of 3.70 U/g. The highest titer in fructooligosaccharides was obtained with an initial inulin concentration of 250 g/L (25%, w/v), and a reaction time of 16 h. Hence, immobilized inulinase proved to be a promising catalyst for fructooligosaccharides production since the formulation is performed through a simple, low-cost, and large-scale applicable methodology.
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    Microfluidic bioreactors for enzymatic synthesis in packed-bed reactors—Multi-step reactions and upscaling
    (Elsevier B.V., 2020-11-10) Brás, Eduardo J.S.; Domingues, Cristiana; Chu, Virginia; Fernandes, Pedro; Conde, João Pedro; HEI-LAB - Human Environment Interaction Lab
    Enzymatic synthesis of biochemical commodities is of upmost importance as it represents a greener alternative to traditional chemical synthesis and provides easier downstream processing strategies compared to fermentation-based processes. A microfluidic system used to optimize the enzymatic production of both levodopa (L-DOPA) and dopamine in both single-step and multistep-reaction sequences with yield of approximately 30 % for L-DOPA production and 70 % for dopamine production is presented. The system for L-DOPA production was then up-scaled (780-fold increase) to a milliliter scale system by maintaining similar mass transport properties resulting in the same yield, space-time yield and biocatalyst yield as its microscale counterpart. The results obtained for yield and biocatalyst yield (351.7 mgL-DOPA mg−1Tyr h−1) were similar to what is reported in the literature for similar systems, however the space-time yield (0.806 mgL-DOPA L−1 h−1) was smaller. This work demonstrates a microfluidic bioreactor that can be used for complex optimizations that can be performed rapidly while reducing the consumption of reagents by immobilizing the catalyst on a carrier which can then be used in a packed-bed reactor, thus extending the enzyme life span.
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    Multi-enzyme systems in flow chemistry
    (Multidisciplinary Digital Publishing Institute (MDPI), 2021) Fernandes, Pedro; de Carvalho, Carla C.C.R.; FE - Faculty of Engineering
    Recent years have witnessed a growing interest in the use of biocatalysts in flow reactors. This merging combines the high selectivity and mild operation conditions typical of biocatalysis with enhanced mass transfer and resource efficiency associated to flow chemistry. Additionally, it provides a sound environment to emulate Nature by mimicking metabolic pathways in living cells and to produce goods through the systematic organization of enzymes towards efficient cascade reactions. Moreover, by enabling the combination of enzymes from different hosts, this approach paves the way for novel pathways. The present review aims to present recent developments within the scope of flow chemistry involving multi-enzymatic cascade reactions. The types of reactors used are briefly addressed. Immobilization methodologies and strategies for the application of the immobilized biocatalysts are presented and discussed. Key aspects related to the use of whole cells in flow chemistry are presented. The combination of chemocatalysis and biocatalysis is also addressed and relevant aspects are highlighted. Challenges faced in the transition from microscale to industrial scale are presented and discussed
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    Mycobacterium vaccae adaptation to disinfectants and hand sanitisers, and evaluation of cross-tolerance with antimicrobials
    (Multidisciplinary Digital Publishing Institute (MDPI), 2020-09) de Carvalho, Carla C.C.R.; Teixeira, Raquel; Fernandes, Pedro; FE - Faculty of Engineering
    Mycobacterium vaccae is being considered as an adjuvant to antituberculosis therapy, tested for the treatment of autoimmune diseases, and as an anti-depressive agent. This bacterium is ubiquitous in the environment and the widespread use of disinfectants and sanitisers may lead to its adaptation to these compounds. In the present study, M. vaccae cells adapted to these compounds mainly by making adjustments in their lipid composition and net surface charge. The modifications in the lipid composition led to changes in membrane permeability which resulted in increased tolerance towards levofloxacin, thioridazine, and omeprazole.
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    Production, characterization, and immobilization of protease from the yeast Rhodotorula oryzicola
    (Wiley-Blackwell, 2021-10) de Oliveira, Juliana Mota; Fernandes, Pedro; Benevides, Raquel Guimarães; de Assis, Sandra Aparecida; FE - Faculty of Engineering
    The protease was produced extracellularly in submerged fermentation by the yeast Rhodotorula oryzicola using different sources of nitrogen and maximum activity (6.54 × 10−3 U/mg) was obtained in medium containing 2% casein (w/v). Purification of the protease by gel filtration chromatography resulted in a 3.07-fold increase of specific protease activity. The optimal pH and temperature for enzyme activity were 6.51 and 63.04 °C, respectively. Incubation in the presence of some salts enhanced enzyme activity, which peaked under 0.01 M BaCl2. The enzyme retained about 90% of enzymatic activity at temperatures 50–60 °C. The commercially available enzyme carriers evaluated, silica gel, Celite 545, and chitosan effectively immobilized the protease. The enzyme immobilized in Celite 545 retained 73.53% of the initial activity after 15 reuse cycles. These results are quite promising for large-scale production and immobilization of protease from R. oryzicola, as the high operational stability of the immobilized enzyme lowers production costs in biotechnological applications that require high enzymatic activity and stability under high temperatures.