Browsing by Author "Rocha, Helena R."
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- 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.
- 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.
- 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.
- Carotenoids diet: digestion, gut microbiota modulation, and inflammatory diseasesPublication . Rocha, Helena R.; Coelho, Marta C.; Gomes, Ana M.; Pintado, Manuela E.Several epidemiologic studies have found that consuming fruits and vegetables lowers the risk of getting a variety of chronic illnesses, including several types of cancers, cardiovascular diseases (CVDs), and bowel diseases. Although there is still debate over the bioactive components, various secondary plant metabolites have been linked to these positive health benefits. Many of these features have recently been connected to carotenoids and their metabolites’ effects on intracellular signalling cascades, which influence gene expression and protein translation. Carotenoids are the most prevalent lipid-soluble phytochemicals in the human diet, are found in micromolar amounts in human serum, and are very susceptible to multiple oxidation and isomerisation reactions. The gastrointestinal delivery system, digestion processes, stability, and functionality of carotenoids, as well as their impact on the gut microbiota and how carotenoids may be effective modulators of oxidative stress and inflammatory pathways, are still lacking research advances. Although several pathways involved in carotenoids’ bioactivity have been identified, future studies should focus on the carotenoids’ relationships, related metabolites, and their effects on transcription factors and metabolism.
- Dual-study exploration: impact of extraction methods on bioavailability, health-related properties, and matrix variationsPublication . Coelho, Marta; Rocha, Helena R.; Morais, Rui; Gomes, Ana M.; Pintado, Manuela E.Objective: This study aimed to evaluate how digestion affects bioactive compounds (BC) in algae matrix and derived extracts, focusing on Osmundea pinnatifida and Codium spp. It also examined the impact of non-absorbed fractions on gut microbiota growth (GMG) and metabolic activity. Methods: The study investigated the influence of hexane extraction on the bioavailability of bioactive compounds (BC) in algae using the INFOGEST in vitro model. Carotenoids, assessed via HPLC, were studied, alongside health-related activities like antioxidant (ABTS and ORAC), anti-hypertensive, and anti-inflammatory methods, and gut microbiota analysis (GMG using human faecal samples analysed by PCR in real-time). Results: In the algae study, the extraction method significantly influenced bioaccessibility. Gastrointestinal digestion simulation revealed varied carotenoids along the gastrointestinal tract (GIT), with only 2.49% beta-carotene absorption. Carotenoids, specially, lycopene, beta- carotene, beta-cryptoxanthin and lutein, in both extracts experienced significant decreases during GIT, particularly under stomach conditions. O. pinnatifida showed no detectable carotenoids, indicating compromised bioaccessibility in complex algae matrices without prior lysis treatment. Carotenoid extracts exhibited noteworthy antioxidant and antidiabetic activities, with lutein demonstrating superiority in the absorbed fraction. Both extracts exhibited high anti- inflammatory and moderately anti-hypertensive activities compared to algae matrices. Relatively to gut microbiota modulation, impact of digested algae highlighted the relative abundance of Bacteroides genus, while for the extracts it was the Bifidobacterium. Conclusions: These results emphasize the crucial role of extraction methods and digestion conditions in shaping the bioavailability and health-related attributes of bioactive compounds in algae, offering valuable insights for further research and application in the realm of functional foods and nutraceuticals.
- Exploring carotenoid-intestinal microbiota interplay: in vitro insights into gastrointestinal interactions and health-enriching effectsPublication . Rocha, Helena R.; Morais, Rui C.; Pintado, Manuela E.; Gomes, Ana M.; Coelho, Marta C.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 (1). These foods are abundant in carotenoids, lipid-soluble phytochemicals (2) known for their health-enhancing properties, including antioxidant, anti-diabetic, and anti-mutagenic effects (3). However, the intestinal microbiota (IM) significantly influences the efficiency of carotenoids (4). The IM plays a vital role in the absorption and metabolism of carotenoids (4). A balanced diet can modulate the composition of the IM, promoting the growth of beneficial microbes and inhibiting harmful ones (5). The IM also synthesizes and releases various metabolites, which can be absorbed into the circulatory system, influencing the host’s health (6). These interactions are crucial for understanding carotenoids' preventive and therapeutic potential. Objective: This study aimed to explore the interaction between carotenoids and the IM during simulated gastrointestinal digestion and absorption. Three carotenoids (beta-carotene, lutein, lycopene), a pigment mixture (MIX), and the alga Osmundea pinnatifida were analyzed. The focus was on understanding how carotenoids affect bioaccessibility, absorption, microbial dynamics, and organic acid production. Additionally, the study assessed the antioxidant, antidiabetic, and antimutagenic properties of carotenoids, providing insights into their potential health benefits.
- Natural pigments recovery from food by-products: health benefits towards the food industryPublication . Magalhães, Daniela; Gonçalves, Ricardo; Rodrigues, Cristina V.; Rocha, Helena R.; Pintado, Manuela; Coelho, Marta C.Given the health risks associated with synthetic colorants, natural pigments have emerged as a promising alternative. These renewable choices not only provide health benefits but also offer valuable technical and sensory properties to food systems. The effective application of natural colorants, however, requires the optimization of processing conditions, exploration of new sources, and development of novel formulations to ensure stability and maintain their inherent qualities. Several natural pigment sources have been explored to achieve the broad color range desired by consumers. The purpose of this review is to explore the current advances in the obtention and utilization of natural pigments derived from by-products, which possess health-enhancing properties and are extracted through environmentally friendly methods. Moreover, this review provides new insights into the extraction processes, applications, and bioactivities of different types of pigments.
- Nutritional profiling and stability analysis of selected microalgaePublication . Rocha, Helena R.; Coelho, Marta; Coelho, Natacha; Morais, Rui; Pintado, Manuela E.; Gomes, Ana M.Microalgae are emerging as a valuable source of nutrients and bioactive compounds1, offering substantial potential for applications in food2. This study provides a comprehensive biochemical characterisation of several microalgae species, including Chaetoceros calcitrans, Cylindrotheca fusiformis, and Nannofrustulum shiloi, focusing on protein content, mineral composition, amino acid profile, and shelf-life stability. In terms of protein content, Chaetoceros calcitrans exhibited the highest concentration at approximately 42% (w/w), followed by Cylindrotheca fusiformis and Nannofrustulum shiloi, which had protein contents of around 31% (w/w) and 27% (w/w), respectively. These findings highlight relevant protein levels and significant variations among different microalgae species, necessitating future studies on their quality and bioavailability. Mineral analysis revealed that Nannofrustulum shiloi contains about 70% calcium. Additionally, this microalgae is rich in sodium (Na), potassium (K), magnesium (Mg), and iron (Fe). Importantly, no heavy metals were detected in any of the analysed species, confirming their safety for food applications. Amino acid profiling of lyophilised biomass from Chaetoceros calcitrans and Cylindrotheca fusiformis showed high concentrations of essential amino acids, including leucine, isoleucine, methionine, phenylalanine, and threonine (ranging from 1.10 to 8.42 g/100 gDW). Shelf-life assessments revealed that Nannofrustulum shiloi maintained a stable amino acid composition over time, with only minor variations between the initial (T0) and subsequent (T2) storage periods (October 2023 and April 2024, respectively), suggesting that the dried biomass of this species retains its nutritional properties during extended storage. Conversely, Cylindrotheca fusiformis displayed notable changes in amino acid levels after storage, indicating that storage conditions can significantly affect its protein composition. These results underscore the nutritional potential and stability of certain microalgae species, particularly Nannofrustulum shiloi, for food applications. The observed variations in protein and amino acid profiles across species provide valuable insights for the development of functional food ingredients derived from microalgae.