Browsing by Author "Gomes, Ana M."
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- Adaptation of Saccharomyces cerevisiae to high pressure (15, 25 and 35 MPa) to enhance the production of bioethanolPublication . Ferreira, Ricardo M.; Mota, Maria J.; Lopes, Rita P.; Sousa, Sérgio; Gomes, Ana M.; Delgadillo, Ivonne; Saraiva, Jorge A.Saccharomyces cerevisiae is a yeast of great importance in many industries and it has been frequently used to produce food products and beverages. More recently, other uses have also been described for this microorganism, such as the production of bioethanol, as a clean, renewable and sustainable alternative fuel. High pressure processing (HPP) is a technology that has attracted a lot of interest and is increasingly being used in the food industry as a non-thermal method of food processing. However, other applications of high pressure (HP) are being studied with this technology in different areas, for example, for fermentation processes, because microbial cells can resist to pressure sub-lethal levels, due to the development of different adaptation mechanisms. The present work intended to study the adaptation of S. cerevisiae to high pressure, using consecutive cycles of fermentation under pressure (at sub-lethal levels), in an attempt to enhance the production of bioethanol. In this context, three pressure levels (15, 25 and 35 MPa) were tested, with each of them showing different effects on S. cerevisiae fermentation behavior. After each cycle at 15 and 25 MPa, both cell growth and ethanol production showed a tendency to increase, suggesting the adaptation of S. cerevisiae to these pressure levels. In fact, at the end of the 4th cycle, the ethanol production was higher under pressure than at atmospheric pressure (0.1 MPa) (8.75 g.L−1 and 10.69 g.L−1 at 15 and 25 MPa, respectively, compared to 8.02 g.L−1 at atmospheric pressure). However, when the pressure was increased to 35 MPa, cell growth and bioethanol production decreased, with minimal production after the 4 consecutive fermentation cycles. In general, the results of this work suggest that consecutive cycles of fermentation under sub-lethal pressure conditions (15 and 25 MPa) can stimulate adaptation to pressure and improve the bioethanol production capacity by S. cerevisiae; hence, this technology can be used to increase rates, yields and productivities of alcoholic fermentation.
- Application of high pressure with homogenization, temperature, carbon dioxide, and cold plasma for the inactivation of bacterial spores: a reviewPublication . Lopes, Rita P.; Mota, Maria J.; Gomes, Ana M.; Delgadillo, Ivonne; Saraiva, Jorge A.Formation of highly resistant spores is a concern for the safety of low-acid foods as they are a perfect vehicle for food spoilage and/or human infection. For spore inactivation, the strategy usually applied in the food industry is the intensification of traditional preservation methods to sterilization levels, which is often accompanied by decreases of nutritional and sensory properties. In order to overcome these unwanted side effects in food products, novel and emerging sterilization technologies are being developed, such as pressure-assisted thermal sterilization, high-pressure carbon dioxide, high-pressure homogenization, and cold plasma. In this review, the application of these emergent technologies is discussed, in order to understand the effects on bacterial spores and their inactivation and thus ensure food safety of low-acid foods. In general, the application of these novel technologies for inactivating spores is showing promising results. However, it is important to note that each technique has specific features that can be more suitable for a particular type of product. Thus, the most appropriate sterilization method for each product (and target microorganisms) should be assessed and carefully selected.
- Bioactive packaging using antioxidant extracts for the prevention of microbial food-spoilagePublication . Moreira, Diana; Gullon, Beatriz; Gullon, Patricia; Gomes, Ana M.; Tavaria, FreniBioactive food packaging is an innovative approach for the prevention of the growth of food-spoilage microorganisms. Four active extracts from agroindustrial subproducts (Eucalyptus wood, almond shells, corn cobs and grape pomace) with demonstrated antioxidant activity have been investigated for bestowing antimicrobial activity to bioactive packaging. To carry out this evaluation, the antioxidant extracts were tested against five food pathogenic bacteria, namely, Escherichia coli, Pseudomonas aeruginosa, Listeria monocytogenes, Staphylococcus aureus and Salmonella spp. The results obtained showed that all the tested extracts inhibited the growth of all five pathogenic bacteria. From the analysis of the minimal bactericidal concentrations (MBCs), the Eucalyptus wood extract was the most active, being necessary only 2% (v/v) to inhibit Pseudomonas aeruginosa, Listeria monocytogenes, and Staphylococcus aureus, whereas almond shells extract were less active requiring 4% (w/v) to inhibit the growth of Escherichia coli and Pseudomonas aeruginosa and the extract from corn cobs was bactericidal against Escherichia coli and Staphylococcus aureus at a concentration of 4% (w/v). After checking their antimicrobial activity, the antioxidant extracts have been incorporated into sodium alginate films and the maintenance of their antimicrobial properties was confirmed. This work showed that the antioxidant extracts from agroindustrial byproducts exhibited antimicrobial activity and were suitable for incorporation into edible films that could be used in bioactive packaging systems.
- Bioactive profile, bioaccessibility and antioxidant activity of diatoms: a comparative studyPublication . Rocha, Helena R.; Coelho, Marta; Coelho, Natacha; Morais, Rui M. S. C.; Pintado, Manuela E.; Gomes, Ana M.Diatoms are microalgae with significant biotechnological potential due to their richness in bioactive compounds, including carotenoids and phenolics, contributing to their antioxidant properties. This study aims to compare the bioactive profile and antioxidant activity of three diatom species: Chaetoceros calcitrans, Nannofrustulum shiloi, and Cylindrotheca fusiformis cultivated in closed Flat Panel photobioreactors by Necton S.A. The biomass was harvested via centrifugation, freeze-dried, milled, and vacuum-packed for subsequent analysis.Carotenoids were extracted using ethanolic extraction assisted by ultrasound and analyzed through HPLC-DAD. The Total phenolic content (TPC) was determined using the Folin-Ciocalteu method, considering both free and bound phenolics to provide a comprehensive understanding of their distribution. Antioxidant activity was evaluated using ABTS, ORAC, and DPPH assays, offering complementary insights into the radical-scavenging potential of the diatom species. Additionally, a bioaccessibility assessment was performed using the standardized INFOGEST in vitro model to evaluate the stability of these bioactive compounds.Carotenoid analysis revealed distinct profiles among the species. N. shiloi exhibited the highest levels of β-carotene and zeaxanthin, highlighting its strong potential as a source of antioxidant pigments, whereas C. fusiformis showed a balanced composition of β-carotene, zeaxanthin, and other carotenoids, suggesting a varied antioxidant capacity. In contrast, C. calcitrans contained comparatively lower levels of these carotenoids. In addition to carotenoids, phenolic compounds play a significant role in the antioxidant potential of these diatoms. The TPC varied significantly, with C. fusiformis presenting the highest levels, followed by N. shiloi and C. calcitrans. Besides the differences in the results of the antioxidant activity among species, all exhibited considerable antioxidant capacity, suggesting the presence of multiple bioactive compounds contributing to distinct yet effective mechanisms of action.These findings highlight the potential of diatoms as sources of natural bioactives, particularly for nutraceutical and pharmaceutical applications. The study underscores the importance of species selection in maximizing bioactive compound yield and antioxidant properties, paving the way for further exploration in functional food and cosmetic industries.
- Bioactivity of probiotic whey cheese: characterization of the content of peptides and organic acidsPublication . Madureira, Ana R.; Soares, José C.; Amorim, Maria; Tavares, Tania; Gomes, Ana M.; Pintado, Maria M.; Malcata, F. XavierBackground Probiotic whey cheeses have been produced for several years. It is recognized that several bacterium-mediated metabolic activities contribute differently to the final sensory and nutritional profiles of dairy products. Hence the metabolic activity of probiotic strains in a whey cheese and their contribution to the bioactivity of such matrices were investigated here, including in particular Bifidobacterium animalis, Lactobacillus acidophilus and Lactobacillus casei. Results Both L. casei and B. animalis produce lactic and acetic acids, whereas L. acidophilus produce mainly lactic acid; these metabolites may be considered bioprotection factors. Water-soluble extracts (WSE) obtained from these cheese matrices were subjected to ultrafiltration through a 3 kDa cut-off membrane, and the eluted peptides were resolved by high-performance liquid chromatography. Different qualitative and quantitative profiles were obtained, depending on the strain. WSE were further assayed for their ability to inhibit angiotensin-converting enzyme; the <3 kDa fraction exhibited higher activities in the case of L. casei and B. animalis than the control and L. acidophilus. Conclusion Whey cheeses with higher nutritional value were those inoculated with L. casei.
- Brazilian fruit pulps as functional foods and additives: evaluation of bioactive compoundsPublication . Paz, Mário; Gúllon, Patricia; Barroso, M. Fátima; Carvalho, Ana P.; Domingues, Valentina F.; Gomes, Ana M.; Becker, Helena; Longhinotti, Elisane; Delerue-Matos, CristinaEight tropical fruit pulps from Brazil were simultaneously characterised in terms of their antioxidant and antimicrobial properties. Antioxidant activity was screened by DPPH radical scavenging activity (126-3987 mg TE/100 g DW) and ferric reduction activity power (368-20819 mg AAE/100 g DW), and complemented with total phenolic content (329-12466 mg GAE/100 g DW) and total flavonoid content measurements (46-672 mg EE/100 g DW), whereas antimicrobial activity was tested against the most frequently found food pathogens. Acerola and acai presented the highest values for the antioxidant-related measurements. Direct correlations between these measurements could be observed for some of the fruits. Tamarind exhibited the broadest antimicrobial potential, having revealed growth inhibition of Pseudomonas aeruginosa. Escherichia coli, Listeria monocytogenes, Salmonella sp. and Staphylococcus aureus. Acai and tamarind extracts presented an inverse relationship between antibacterial and antioxidant activities, and therefore, the antibacterial activity cannot be attributed (only) to phenolic compounds.
- Can growth of nannochloropsis oculata under modulated stress enhance its lipid-associated biological properties?Publication . Sousa, Sérgio C.; Machado, Manuela; Freitas, Ana C.; Gomes, Ana M.; Carvalho, Ana P.Nannochloropsis oculata is well-recognized as a potential microalgal source of valuable compounds such as polyunsaturated fatty acids, particularly, eicosapentaenoic acid (EPA). The content and profile of these lipids is highly dependent on the growth conditions and can, therefore, be tailored through modulation of the growth parameters, specifically, temperature. Moreover, biological activities are composition dependent. In the present work, lipid extracts obtained from N. oculata, grown under constant temperature and under modulated temperature stress (to increase EPA content; Str) were characterized by GC-FID and several bioactivities were evaluated, namely, antioxidant (L-ORACFL), cytotoxic (MTT), adipolytic, anti-hepatic lipid accumulation (steatosis), and anti-inflammatory properties. Both extracts exhibited antioxidant activity (c.a. 49 µmol Troloxequivalent/mgextract) and the absence of toxicity (up to 800 µg/mL) toward colon and hepatic cells, adipocytes, and macrophages. They also induced adipolysis and the inhibition of triglycerides hepatic accumulation, with a higher impact from Str. In addition, anti-inflammatory activity was observed in the lipopolysaccharide-induced inflammation of macrophages in the presence of either extract, since lower levels of pro-inflammatory interleukin-6 and interferon-β were obtained, specifically by Str. The results presented herein revealed that modulated temperature stress may enhance the health effects of N. oculata lipid extracts, which may be safely utilized to formulate novel food products.
- Carotenoid-microbiota dynamics: in vitro analysis of gut modulation and associated health benefitsPublication . Rocha, Helena R.; Morais, Rui C.; Pintado, Manuela E.; Gomes, Ana M.; Coelho, Marta C.Introduction: Carotenoids, natural lipid-soluble pigments abundant in various fruits and vegetables, play a significant role in our diet by adding vibrant colours to our meals (1). Humans and animals cannot synthesize these compounds, emphasizing the importance of dietary intake for reaping their benefits (2,3). Besides enhancing the visual appeal of food, carotenoids are renowned for their health advantages, serving as potent antioxidants and supporting eye health and immune function (3). However, realizing the full potential of carotenoids for human health faces challenges, primarily centered around their bioaccessibility (4,5). The journey of carotenoids from ingestion to beneficial impact is filled with obstacles, with digestion presenting a significant challenge. The chemical composition of carotenoids encounters resistance and degradation within protein complexes and the intricate structures of plant cell walls during digestion. Various factors such as dietary sources, food composition, matrix structure, lipid presence, and interactions with other compounds further complicate the bioaccessibility of carotenoids (6). Noncommunicable diseases (NCDs), responsible for 41 million deaths each year, are often associated with unhealthy dietary habits. To combat this, nutrition and health organizations recommend a diet rich in fruits and vegetables (5). These foods are abundant in carotenoids, lipid-soluble phytochemicals known for their health-enhancing properties, including antioxidant, anti-diabetic, and anti-mutagenic effects (3,7). The intestinal microbiota (IM) significantly influences the efficiency of carotenoids (8). The IM plays a vital role in the absorption and metabolism of carotenoids, as a balanced diet can modulate the composition of the IM, promoting the growth of beneficial microbes and inhibiting harmful ones. Additionally, the IM synthesizes and releases various metabolites, which can be absorbed into the circulatory system, influencing the host’s health (9). These interactions are crucial for understanding carotenoids' preventive and therapeutic potential. Objective: This study aimed to investigate the interaction between carotenoids and the intestinal microbiota during simulated gastrointestinal digestion and absorption. It examined three specific carotenoids - beta-carotene, lutein, and lycopene - alongside a pigment mixture (MIX) and the alga Osmundea pinnatifida. The research focused on how these carotenoids influence bioaccessibility, absorption, microbial dynamics, and organic acid production. The study evaluated carotenoids' antioxidant, antidiabetic, and antimutagenic properties, offering insights into their potential health benefits. Conclusions: Through the in vitro digestion simulation, it was observed distinct transformations in carotenoids, indicating intricate changes during digestion; Recovery indexes underscored the difficulty in retrieving carotenoids during digestion, highlighting the complexity of their fate in the digestive process. Carotenoid’s tested groups stimulated the production of organic acids, notably succinic (~6.4 g/L), acetic (~2.75 g/L), butyric (~0.47 g/L), and propionic (~2.78 g/L) acids; The analysis of the IM revealed Bacteroidota, Bacillota, Pseudomonadota, and Actinomycetota as the main phyla present. Carotenoids significantly increased the relative abundance (RA) of the Lachnospiraceae family by 77.8% while decreasing the RA of several bacteria, including Lactobacillus by 1.27%, Enterococcus by 16.3%, Streptococcus by 8.80%, and Bifidobacterium by 18.3%, which is consistent with previous studies. The Mix group demonstrated higher antioxidant activity, particularly when located outside the membrane, compared to other carotenoid groups; Lutein and the Mix groups showed effectiveness in anti-diabetic activity, especially when present within the membrane. Carotenoid-digested samples exhibited antimutagenic effects, suggesting their potential to support cell development and act as a shield against mutations.
- Carotenoid-microbiota dynamics: in vitro analysis of gut modulation and associated health benefitsPublication . Rocha, Helena R.; Coelho, Marta; Coelho, Natacha; Morais, Rui M.S.C.; Pintado, Manuela E.; Gomes, Ana M.Carotenoids are bioactive compounds with recognized health benefits, yet their full potential is limited by poor bioaccessibility and complex interactions within the gastrointestinal tract. This study aimed to investigate the digestion, absorption, and gut microbiota modulation of three carotenoids (β-carotene, lutein, lycopene), a mixed carotenoid solution, and the red alga Osmundea pinnatifida. Using a simulated gastrointestinal digestion model (INFOGEST), combined with dialysis and in vitro fecal fermentation, we evaluated carotenoid recovery, antioxidant capacity, antidiabetic and antimutagenic activities, and short-chain fatty acid (SCFA) production. Results demonstrated low carotenoid recovery and structural transformation during digestion, with the mixed carotenoid solution exhibiting the highest antioxidant activity. Lutein and the mixed group also showed significant α-glucosidase inhibition, suggesting antidiabetic potential. Fermented samples increased the production of SCFAs and significantly modulated the gut microbiota, enhancing beneficial taxa such as Lachnospiraceae. These findings highlight the potential of carotenoids and O. pinnatifida in supporting gut health and preventing noncommunicable diseases through microbiota-mediated mechanisms.
- Carotenoids and intestinal harmony: exploring the link for healthPublication . Rocha, Helena R.; Pintado, Manuela E.; Gomes, Ana M.; Coelho, Marta C.Carotenoids, prominent lipid-soluble phytochemicals in the human diet, are responsible for vibrant colours in nature and play crucial roles in human health. While they are extensively studied for their antioxidant properties and contributions to vitamin A synthesis, their interactions with the intestinal microbiota (IM) remain poorly understood. In this study, beta (β)-carotene, lutein, lycopene, a mixture of these three pigments, and the alga Osmundea pinnatifida were submitted to simulated gastrointestinal digestion (GID) and evaluated on human faecal samples. The results showed varying effects on IM metabolic dynamics, organic acid production, and microbial composition. Carotenoid exposure influenced glucose metabolism and induced the production of organic acids, notably succinic and acetic acids, compared with the control. Microbial composition analysis revealed shifts in phyla abundance, particularly increased Pseudomonadota. The α-diversity indices demonstrated higher diversity in β-carotene and the pigments’ mixture samples, while the β-diversity analysis indicated significant dissimilarity between the control and the carotenoid sample groups. UPLC-qTOF MS analysis suggested dynamic changes in carotenoid compounds during simulated fermentation, with lutein exhibiting distinct mass ion fragmentation patterns. This comprehensive research enhances our understanding of carotenoid-IM interactions, shedding light on potential health implications and the need for tailored interventions for optimal outcomes.