Browsing by Author "Gomes, A. M."
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- Akkermansia muciniphila antimicrobial susceptibility profilePublication . Barbosa, J. C.; Machado, D.; Almeida, D.; Andrade, J. C.; Freitas, A. C.; Gomes, A. M.
- Alga Fucus sp. extracts to produce edible filmsPublication . Martins, V.; Machado, M.; Costa, E.; Gomes, A. M.; Poças, F.; Pintado, M.; Morais, R. M. S. C.; Morais, A. M. M. B.Introduction: Macroalgae are a good source of nutrients, such as carbohydrates (dietary fiber and polysaccharides), proteins, lipids and minerals [1,2]. Fucus sp. is composed of valuable bioactive compounds, such as fucoxanthin, vitamins, water-soluble (vitamin C and of complex B) and fat-soluble (vitamins A, D, E and K), phenolic compounds, lipids (MUFA and PUFA), and polysaccharides (fucoidans and alginic acid) [1]. This brown alga has been associated with health benefits, such as antioxidant, antimicrobial, anti-tumoral and anti-cancer properties [2]. Its application in the production of edible films presents high potential in food packaging, extending the shelf life of food products. Objectives: To evaluate the antioxidant activity and cytotoxicity bioactive extracts from Fucus sp. To produce an edible film based on PS enriched with the bioactive extracts. To test the antioxidant activity of the edible film. To test physico-chemical properties of the edible film, such as the color, thickness, solubility and water vapor permeability. Conclusions: Extraction at 300 W during 20 minutes is recommended for highest TPC and AA of the liquid extract. This extract showed no cytotoxicity for cells line HaCat. The edible film based on the PS extracted from Fucus sp. enriched with bioactives extracted also from this alga shows antioxidant activity, presents a high water vapor permeability, and 100 % solubility in water, which simulates hydrophilic foods, and lower solubility in hydroalcoholic solutions, which simulate hydrophobic foods. It has a brown color, characterized by relatively low luminosity and saturation values. This edible film has potential to be used in food packaging, whereas presenting high biodegradability.
- Analyzing the potential of selected gut commensal strains to produce antimicrobial peptides: phenotypic and in silico approachesPublication . Fonseca, M.; Machado, D.; Vedor, R.; Andrade, J. C.; Gomes, A. M.; Barbosa, J. C.The World Health Organization estimates that the number of antibiotic resistance-related deaths could reach 10 million by 2050 [1]. Given the dynamics and high diversity of microorganisms that inhabit the gastrointestinal tract, this is the ideal place to discover new antimicrobial peptides (AMP) to replace traditional antibiotics [2]. Among the most extensively studied members are the commensal strains Akkermansia muciniphila DSM 22959 and Faecalibacterium duncaniae DSM 17677, which are reported to have a beneficial impact on intestinal health [3;4]. Antimicrobial peptides are small molecules that act as the first line of defense against microbial invaders, playing a vital role in the innate immune system [5]. One approach to identify new strategies to combat antimicrobial resistance is to evaluate the ability of these bacteria to produce AMP.
- Antimicrobial activity and lipid profile of seaweed extracts from the North Portuguese coastPublication . Mendes, M.; Pereira, R.; Pinto, I. Sousa; Carvalho, A. P.; Gomes, A. M.Seaweeds or marine macroalgae are a potential renewable resource in the marine environment and can represent a source of new natural compounds for human nutrition. This experimental work focused on the selection of a suitable extraction method, using Gracilaria vermiculophylla as a model, followed by the characterization of the antimicrobial activity of different solvent extracts of Gracilaria vermiculophylla, Porphyra dioica and Chondrus crispus, both from wild and from an integrated multi-trophic aquaculture system (IMTA), collected in the north of Portugal. Additionally, the fatty acid profile of the seaweed extracts was also investigated. Extraction tests included the definition of the physical state of the seaweed, temperature and type of solvents to be used during the process. Results revealed that test organisms (Gram negative and Gram positive bacteria as well as one yeast species) were more sensitive to extracts obtained with dried algae, processed continuously at higher temperatures. Results from antimicrobial activity of wild and IMTA seaweed extracts showed stronger antimicrobial activity in extracts of ethyl acetate when compared with those from methanol and diethyl ether; furthermore, among the type of microorganisms tested, there was tendency for inhibition of the Gram positive ones. In general, there appears to be a higher antimicrobial activity for the microorganisms under study in extracts obtained from aquaculture species, when compared with the wild ones. The fatty acid profile of ethyl acetate extracts revealed a predominance of saturated fatty acids (SFA), especially palmitic acid (16:0), followed by polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA). A higher content of fatty acids in aquaculture extracts of Gracilaria vermiculophylla and Porphyra dioica was also observed.
- Biochemical composition and functional application of enzyme-assisted extracts from leaves of Cannabis sativa L.Publication . Januskevice, V.; Gomes, A. M.; Sousa, S.; Cesoniene, L.; Streimikyte, P.; Viskelis, P.; Urbonaviciene, D.Enzyme-assisted extraction (EAE) has recently gained attention for its effectiveness and eco-friendly manner of extracting valuable compounds, enhancing their nutritional value at a lower cost. Cannabis sativa L. is a widely distributed and one of the oldest plant species in the Cannabaceae family. However, the plant leaves have not been widely studied for their biochemical and functional applications. This study aimed to investigate the biochemical composition, antioxidant activity, and prebiotic potential of EAE from C. sativa leaves. Extracts were obtained under optimal conditions (3:15 h of extraction, temperature 45°C, pH 4.9, and 1% enzyme (v/w of dry matter)). The extractions were performed using Viscozyme L, Cellulase enzymes, and control without enzyme. The antioxidant activity of C. sativa leaf extracts was assessed using ABTS•+, FRAP, and ORAC assays, while the total phenolic content was obtained using the Folin-Ciocalteu method. The prebiotic potential of C. sativa leaf extracts was evaluated in an in vitro screening model using probiotic strains Lactobacillus casei 01 and Bifidobacterium animalis BLC. Extracts were tested at 5% (v/v) and 50% (v/v) concentrations. The results indicated that the yield after EAE with Viscozyme L enzyme mixture increased by up to 44% compared with EAE with Cellulase enzyme and control. Moreover, the highest antioxidant activity was established in EAE with Viscozyme L enzyme extract within all tested assays. Furthermore, all tested extracts were established to possess prebiotic potential with tested probiotic strains, but the greatest results were obtained in EAE with Viscozyme L enzyme mixture extract. In conclusion, EAE may be an effective and sustainable method for biorefining bioactive compounds, potentially applicable in high-value functional foods and nutraceuticals.
- Characterization of 70.5% cocoa content dark chocolate incorporated with Bifidobacterium animalis subspecies lactis BB-12®Publication . Vedor, R.; Machado, D.; Barbosa, J. C.; Gomes, A. M.Currently, probiotics are defined as "live microorganisms that, when administered in adequate amounts, confer a health benefit on the host” [1].Bifidobacterium animalis subsp. lactis BB-12® is one of the most common probiotics used as a food supplement [2]. Chocolate is one of the most popular and appealing culinary products, with various cocoa percentages available to consumers [3;4]. Several studies have suggested that chocolate, particularly dark chocolate, may offer health benefits due to the presence of a diverse array of bioactive compounds [5]. In this sense, a growing interest in using chocolate as a carrier for probiotic delivery has emerged.
- Characterization of alga Fucus sp. extracts and residues and their application in producing edible filmsPublication . Martins, V.; Coelho, M.; Machado, M.; Costa, E.; Gomes, A. M.; Poças, F.; Pintado, M.; Morais, R. M. S. C.; Morais, A. M. M. B.Introduction: Macroalgae are a good source of nutrients, such as carbohydrates (dietary fiber and polysaccharides), proteins, lipids and minerals, and they are sustainable, because they do not compete with food crops for arable land and potable water [1,2]. Fucus sp. is composed of valuable bioactive compounds, such as fucoxanthin, vitamins, water-soluble vitamins (vitamin C and of complex B) and fat-soluble vitamins (vitamins A, D, E and K), phenolic compounds, lipids (MUFA and PUFA), and polysaccharides (fucoidans and alginic acid) [1]. This brown alga has been associated with health benefits, with antioxidant, antimicrobial, anti-tumoral and anti-cancer properties [2]. Its application in the production of edible films presents high potential in food packaging, extending the shelf life of food products. Objectives: The integral valorization of Fucus sp. macroalgae, by extracting bioactive compounds, such as phenolic compounds, and extracting polysaccharides (PS). To evaluate the cytotoxicity and antioxidant activity of the bioactive extracts. To produce an edible film based on PS enriched with the bioactive extracts from Fucus sp. To test the physico-chemical properties of the edible film, such as the solubility. The nutritional characterization of the residues from the extractions. Conclusions: Extraction at 300 W during 20 minutes is recommended for highest TPC and AA of the liquid extract. This extract showed no cytotoxicity for cells line HaCat. The edible film based on the PS extracted from Fucus sp. enriched with bioactives extracted also from this alga presents 100 % solubility in water, which simulates hydrophilic foods, and lower solubility in hydroalcoholic solutions, which simulate hydrophobic foods. This edible film has potential to be used in food packaging, whereas presenting high biodegradability.
- Characterization of potential CLA-producing strains according to LA tolerancePublication . Fontes, A. L.; Pimentel, L. L.; Salsinha, A. S.; Cardoso, B.; Andrade, J. C.; Rodríguez-Alcalá, L. M.; Gomes, A. M.Introduction: Linoleic acid (LA) present in ruminants diet goes through a series of reactions within the rumen, called the biohydrogenation pathway. This pathway ends up converting LA to stearic acid (C18), but several intermediate products are formed, such as conjugated linoleic acid (CLA) isomers, which have been extensively studied for their potential bioactive properties1,2. Different ruminal bacteria are involved in this process, however, strains of lactobacilli, bifidobacteria and propionibacteria isolated from human intestine and dairy products have also demonstrated the ability to produce those fatty acids3. Most in vitro CLA production assays normally test potential producing strains by culturing them in the presence of a pure LA solution at 0.5 mg/mL or less4. However, possibly there are some strains that can tolerate higher concentrations of LA and if they are producers, CLA yields may probably be higher. Objective: The major aim of this work was to determine the maximum LA concentration that potential CLA-producing strains can tolerate in further in vitro production assays. Conclusions: In conclusion, potential CLA-producing strains exhibit different LA tolerance degrees, being lactobacilli the more tolerant at the highest LA concentration assayed. Currently overlooked, this is an important parameter to consider in future production tests.
- Chitosan as natural food preservative for sauces: a proof of conceptPublication . Costa, E. M.; Silva, S.; Silva, N.; Couto, J. A.; Gomes, A. M.; Pintado, M. M.Introduction: Nowadays, consumers demand more natural, nutritionally balanced, less caloric, and minimally processed foods leading to the emergence of sauces with low fat content and without chemical preservatives. This market pressure has led to the modification of a well-established and microbiologically stable matrix, triggering the search for new antimicrobial compounds of natural origin, compounds whose inhibitory efficacy must be studied [1]. Chitosan has attracted attention as a potential food preservative of natural origin due to its antimicrobial activity against a wide range of foodborne pathogens and contaminants. However, the antimicrobial capacity of chitosan, despite being extensively reported, is primarily based upon in vitro trials, where the compound, unimpeded, acts upon microorganisms. Currently, inclusion of chitosan in a food matrices is in its early steps with works reporting the application of chitosan in bread, egg, fruits, vegetables, juices, meat, milk and others, with various degrees of success [2]. In food sauces examples of chitosan application are few and scarce, as most works report on the usage of chitosan as an emulsifier or a emulsifier stabilizer and only Roller and Covill [3] described the successful usage of a chemically altered chitosan as a food preservative. As such, in this work we sought to ascertain the potential of chitosan as a viable, natural, alternative to traditional food preservatives used in food sauces, namely ketchup, mayonnaise and mustard, through assessment of the effect of chitosan containing sauces on the inhibition of lactic acid bacteria isolated therefrom and sensorial analysis of the developed prototypes.
- Effect of food matrix on antimicrobial activity upon food spoilage Lactic Acid BacteriaPublication . Costa, E. M.; Silva, S.; Matias, C.; Matias, O.; Couto, J. A.; Gomes, A. M.; Pintado, M. M.Lactic acid bacteria (LAB) have been used in foodstuffs due to the desirable effects on the organoleptic and functional characteristics; however they can also cause food spoilage by producing off-flavours, carbon dioxide and textural changes. In such circumstances, their intrinsic high resistance to acidic conditions and antimicrobials poses a problem to the food industry. So it is important to select amongst the food additives those that assure LAB inhibition in acid and complex food matrices assuring safety and quality preservation. In this work we describe the antimicrobial efficiency of sodium diacetate in two prototypes of mayonnaise and ketchup. To that end both matrices (ketchup and mayonnaise) formulated with the selected antimicrobial agent were inoculated with a LAB isolated from previously spoiled sauces and the capability to reduce their initial viable cell numbers was evaluated. The results obtained showed that the inclusion of this antimicrobial into both matrices was not completely successful. While in the ketchup prototype revealed high antimicrobial activity reducing, in 24 h, LAB viable counts by 5.37 log CFU/g, in the mayonnaise only 1 log CFU/g reduction was observed in the same time frame. A probable cause for this discrepancy is the higher fat content of mayonnaise that may be blocking the antimicrobial activity. In conclusion the results obtained show the need to adapt the antimicrobial solution to different complex matrices, since several interactions between food matrix and antimicrobial components may occur
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