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Browsing by Author "Vilas-Boas, Ana A."

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  • Functional ingredients and additives from lemon by-products and their applications in food preservation: a review
    Publication . Magalhães, Daniela; Vilas-Boas, Ana A.; Teixeira, Paula; Pintado, Manuela
    Citrus trees are among the most abundant fruit trees in the world, with an annual production of around 124 million tonnes. Lemons and limes are among the most significant contributors, producing nearly 16 million tonnes per year. The processing and consumption of citrus fruits generates a significant amount of waste, including peels, pulp, seeds, and pomace, which represents about 50% of the fresh fruit. Citrus limon (C. limon) by-products are composed of significant amounts of bioactive compounds, such as phenolic compounds, carotenoids, vitamins, essential oils, and fibres, which give them nutritional value and health benefits such as antimicrobial and antioxidant properties. These by-products, which are typically discarded as waste in the environment, can be explored to produce new functional ingredients, a desirable approach from a circular economy perspective. The present review systematically summarizes the potential high-biological-value components extracted from by-products to achieve a zero-waste goal, focusing on the recovery of three main fractions: essential oils, phenolic compounds, and dietary fibres, present in C. limon by-products, and their applications in food preservation.
    2023-03-04Journal article Open access Show more
  • Functional mango peel powders: what is the impact of different drying methods on their phytochemical composition and antioxidant activity?
    Publication . Marçal, Sara; Araújo-Rodrigues, Helena; Vilas-Boas, Ana A.; Campos, Débora A.; Pintado, Manuela
    In 2018, mangoes were among the six most-produced fruits worldwide (1). Annually, 15–25 million tons of mango byproducts are generated (2). According to the previous studies, one of the best strategies to valorise mango peels in the food industry is to convert them into powders (2). Hence, this study aims to evaluate the impact of different drying methods on mango peels’ nutritional composition, bioactive compounds, and antioxidant activity. Firstly, mango peels were washed with peracetic acid (PAA) (mango peels to disinfectant solution ratio: 1:1 (kg:L); PAA concentration: 27 mg/mL; disinfection time: 19 min) (fresh sample (FS))(1) . Then, they were submitted to three different processes: freeze-drying (freeze-dried samples (FD)); hot-air drying at 65 ºC for 48 h, with constant air circulation (hot-air dried samples (HAD)); and freezing at -20 ºC for 30 days and then hot-air drying at 65 ºC for 48 h, with constant air cir- culation (Frozen and hot-air dried samples (FZ+HAD)). The dry matter, soluble and insoluble fiber, protein, fat, and ash of these four samples were determined according to AOAC methods. Carotenoids were extracted with hexane: acetone (50%:50%; v:v). Moreover, free and bound phenolic compounds were obtained by performing a methanolic extraction and an alkaline and acid hydrolysis, respectively. The main mango peels’ carotenoids and phenolic compounds were identified using HPLC analysis. Finally, total free and bound phenolic compounds were quantified through Folin-Ciocalteu method, and their antioxidant activity was evaluated through DPPH and ABTS assays. Overall, the different drying methods did not impact mango peels’ soluble and insoluble fiber, protein, fat, and ash con- tent. Considering the four analysed samples, these parameters ranged between 19.47±0.48 - 20.73±0.44, 19.60±0.62 – 21.04±1.89, 4.93±0.13 – 6.02±0.44, 1.56±0.01 – 1.92±0.03, and 2.05±0.19 – 2.89±0.11, respectively. All of them were ex- pressed in g/100DW. However, drying markedly impacted mango peels’ phenolic compounds, carotenoids, and antioxidant activity. All drying methods caused a statistically significant decrease in total free phenolic compounds (FS: 12.76±0.80 mg of gallic acid equivalents (GAEs) / gDW; FD: 10.04±0.17 mg of GAEs/ gDW; HAD: 7.69±0.12 mg of GAEs/ gDW; FZ+HAD: 6.63±0.05 mg of GAEs/ gDW). The main free phenolic compounds identified in all samples were mangiferin (FS: 873.61±71.43; FD: 863.71±6.15; HAD: 647.61±1.86 FZ+HAD: 447.88 ± 5.37), gallic acid (FS: 590±30.93; FD: 650.48±11.85; HAD: 850.29±10.99 FZ+HAD: 523.60 ±10.83), quercetin-3-O-galactoside (FS: 467.20±34.15; FD: 464.31±1.97; HAD: 391.07±4.29 FZ+HAD: 502.41±22.73) and penta-O-galloyl-β-D-glucose (FS: 397.60±22.56; FD: 384.30±5.63; HAD: 362.88±5.03 FZ+HAD: 167.94 ±3.36). Compared with other dried peels, FZ+HAD samples showed a significantly lower amount of these compounds (excluding quercetin-3-O-galactoside). Gallic acid (basic hydrolyse: FS: 476.99±52.51; FD: 42.65±0.94; HAD: 152.66±15.35 FZ+HAD: 207.74±4.23; acid hydrolyse: FS: 83.00±12.98; FD: 12.27±0.16; HAD: 23.25±0.02 FZ+HAD: 28.26±0.76) and 4–hydroxybenzoic acid (basic hydrolyse: FS: 59.26±5.00; FD: 16.69.65±0.69; HAD: 50.39±4.17 FZ+HAD: 46.15±6.23; acid hydrolyse: FS: 23.13±0.75; FD: 2.58±0.14; HAD: 6.12±0.25 FZ+HAD: 5.63±0.50) were the main phenolic compounds obtained in both basic and acid hydrolysis. All phenolic compound amounts were expressed in μg/ gDW. Regarding carotenoids, drying also had a negative impact. FS samples contained violaxanthin (2.94±0.05 μg/gDW), lutein (4.83±0.52 μg/gDW), and β-carotene (104.46 ±0.25 μg/gDW), while in dried samples, only lutein (lower than quanti- fication limit) and β-carotene (FD: 36.19 ± 0.53 μg/gDW HAD: 36.06 ± 2.45 μg/gDW; FZ+Oven: 40.65 ± 3.66 μg/gDW) were detected. All drying methods impaired the antioxidant activity of free and bound phenolic compounds. As expected, freeze drying enabled a better preservation of free phenolic compounds’ antioxidant activity. No statistically significant differences were found between the antioxidant activity of free phenolic compounds from HAD and FZ+HAD samples. Concerning bound phenolic compounds’ antioxidant activity, overall, no significant differences were detected between dried samples. This study showed that mango peel powders had a high amount of fiber, phenolic compounds, and carotenoids, suggest- ing that they have a high potential to be used as functional ingredients. However, drying processes, namely hot air drying, should be optimized to enable better preservation of mango peels’ bioactive compounds and antioxidant activity.
    2023Book part Open access Show more
  • Impact of circular brewer's spent grain flour after in vitro gastrointestinal digestion on human gut microbiota
    Publication . Bonifácio-Lopes, Teresa; Catarino, Marcelo D.; Vilas-Boas, Ana A.; Ribeiro, Tânia B.; Campos, Débora A.; Teixeira, José A.; Pintado, Manuela
    Brewer's spent grain (BSG) solid residues are constituted by dietary fibre, protein, sugars, and polyphenols, which can have potential effects on human health. In this study, for the first time, the flours obtained from solid residues of solid-liquid extraction (SLE) and ohmic heating extraction (OHE) were applied throughout the gastrointestinal digestion simulation (GID), in order to evaluate their prebiotic potential and in vitro human gut microbiota fermentation. The results showed that the digestion of BSG flours obtained by the different methods lead to an increase throughout the GID of total phenolic compounds (SLE: from 2.27 to 7.20 mg gallic acid/g BSG-60% ethanol:water (v/v); OHE: 2.23 to 8.36 mg gallic acid/g BSG-80% ethanol:water (v/v)) and consequently an increase in antioxidant activity (ABTS-SLE: from 6.26 to 13.07 mg ascorbic acid/g BSG-80% ethanol:water (v/v); OHE: 4.60 to 10.60 mg ascorbic acid/g BSG-80% ethanol:water (v/v)-ORAC-SLE: 3.31 to 14.94 mg Trolox/g BSG-80% ethanol:water (v/v); OHE: from 2.13 to 17.37 mg Trolox/g BSG-60% ethanol:water (v/v)). The main phenolic compounds identified included representative molecules such as vanillic and ferulic acids, vanillin and catechin, among others being identified and quantified in all GID phases. These samples also induced the growth of probiotic bacteria and promoted the positive modulation of beneficial strains (such as Bifidobacterium spp. and Lactobacillus spp.) present in human faeces. Moreover, the fermentation by human faeces microbiota also allowed the production of short chain fatty acids (acetic, propionic, and butyric). Furthermore, previous identified polyphenols were also identified during fecal fermentation. This study demonstrates that BSG flours obtained from the solid residues of SLE and OHE extractions promoted a positive modulation of gut microbiota and related metabolism and antioxidant environment associated to the released phenolic compounds.
    2022-07-30Journal article Open access Show more
  • Impact of extraction process in non-compliant ‘Bravo de Esmolfe’ apples towards the development of natural antioxidant extracts
    Publication . Vilas-Boas, Ana A.; Oliveira, Ana; Ribeiro, Tânia B.; Ribeiro, Sónia; Nunes, Catarina; Gómez-García, Ricardo; Nunes, João; Pintado, Manuela
    The ‘Bravo de Esmolfe’ apple (BE) is rich in antioxidants and represents one of the most important traditional cultivars in Portugal. A large amount of non-compliant BE, with no market value, it is generated every year. Thus, an effort to find value-added solutions is of utmost importance. For the first time, green extraction (microwave-assisted-extraction (MAE) and ultrasound-assisted-extraction (UAE)) were compared against conventional extraction (with (CET) and without temperature (CE)) to select the most efficient process to produce a natural antioxidant extract from non-compliant BE. The results showed that MAE and CET are good methodologies for developing a BE antioxidant extract. However, MAE is more sustainable than CET, requiring less time to reach high temperatures. The MAE-extract showed great antioxidant activity (14.80 ± 0.70 mg TE/g DE by ORAC, 3.92 ± 0.25 mg AAE/g DE by ABTS, and 5.11 ± 0.13 mg TE/g DE by DPPH). This extract revealed high amount of chlorogenic acid (0.48 ± 0.07 mg/g DE), (-)-epicatechin (0.30 ± 0.02 mg/g DE) and phloridzin (0.13 ± 0.01 mg/g DE). This study shows that non-compliant BE is a useful source of antioxidants, being a sustainable way for the recovery of value-added compounds from the rejected fruit in line with sustainable and circular bioeconomy principles.
    2021-07-01Journal article Open access Show more
  • Impact of functional flours from pineapple by-products on human intestinal microbiota
    Publication . Campos, Débora; Coscueta, Ezequiel R.; Vilas-Boas, Ana A.; Silva, Sara; Teixeira, José A.; Pastrana, Lorenzo M.; Pintado, Maria Manuela
    Solid fractions from pineapple stems and peels are constituted by structural carbohydrates coupled with dietary fibre, simple sugars, but also vitamins and polyphenols, which together can have potential effects on human health. The present studies report for the first time the bioavailability and bioaccessibility of pineapple byproducts fractions throughout simulated gastrointestinal tract, evaluates prebiotic potential and in vitro human microbiota fermentation. The pineapple flours promoted the human faeces fermentation through growth of beneficial strains, being corroborated by the decrease of simple sugars and the production of healthy organic acids (acetic, propionic and butyric acids) - well known short chain fatty acids. On the other hand, a high phenolic compounds content was release through flours digestion, developing an antioxidant environment within human gut. Thus, was possible to conclude that pineapple flour promoted a positive modulation in the overall system, proving a synergetic interaction of dietary fibre and polyphenols upon human microbiota.
    2020Journal article Open access Show more
  • Impact of in vitro gastrointestinal digestion on upcycled blackcurrant dried extract
    Publication . Sousa, Ana Sofia; Vilas-Boas, Ana A.; Gómez-García, Ricardo; Alonso, Mercedes; De Biasio, Filomena; Gorgoglione, Domenico; Fajardo, Paula; House, Alistair; Pintado, Manuela
    Pomaces, the major by-product of fruit juice processing industries, is rich in bioactive compounds. Among them, polyphenols boost the body's antioxidant capacity, improving cardiovascular health, reducing the risk of diabetes and inflammation, and promoting intestinal microbiota health. Blackcurrant (Ribes nigrum L.) is a highly antioxidant berry rich in anthocyanins, a polyphenols class that also gives the fruit a black-purple color. Thus, blackcurrant pomace polyphenols have the potential to be functional food ingredients that can enhance sustainability in the agri-food processing chain with health benefits. In order to have a beneficial effect on health, polyphenols must be bioaccessible. This means they must be released from the food matrix during gastrointestinal digestion (GID) and available for absorption in the gut.This study aimed to assess the bioaccessibility of anthocyanins and the antioxidant activity of polyphenolic extract from blackcurrant pomace. For this purpose, an enzymatic method was used to release the polyphenols from the pomace, which were then spray-dried. The INFOGEST 2.0 protocol was used to simulate the in vitro GID of the powder. The anthocyanins profile (HPLC-DAD), total phenolic content (TPC, Folin-Ciocalteu method), antioxidant capacity (ABTS, DPPH), and cytotoxicity (PrestoBlue assay) were evaluated.The blackcurrant powder extract initially contained over 900 mg/L of total anthocyanins. The major compounds are cyanidin-3-O-glucoside (54%), pelargonidin-3-O-glucoside (19%), and delphinidin-3-O-glucoside (18%). The anthocyanins remained stable during the gastric phase of GID, with a full recovery index of 20% and 12% for cyanidin-3-O-glucoside. Still, they drastically decreased in the intestinal stage due to a pH change that caused a break in the anthocyanin B-ring. The TPC of the extract significantly reduced during the oral and gastric phases but increased slightly during the intestinal phase, with a 19% recovery index. The extract's antioxidant activity decreased, resulting in a bioaccessibility index of 19% and 23% for ABTS and DPPH scavenging activity, respectively. Despite a decrease in TPC along the GID, the extract still exhibited antioxidant capacity due to the existence of various phenolic compounds, specifically hydroxybenzoic and hydroxycinnamic acids, resulting from the degradation/transformation of anthocyanins3. A 2.5% (w/v) of antioxidant extract powder is safe for food formulations.Thus, this work provides insights into the effects of GID on anthocyanins and the potential use of blackcurrant pomace as a source of bioactive ingredients, promoting a circular economy.
    2024-04-11Conference object Open access Show more
  • Impact of simulated human gastrointestinal digestion on the bioactive fraction of upcycled pineapple by-products
    Publication . Gómez-García, Ricardo; Vilas-Boas, Ana A.; Oliveira, Ana; Amorim, Manuela; Teixeira, José A.; Pastrana, Lorenzo; Pintado, Maria Manuela; Campos, Débora A.
    Pineapple by-products (peels and stems) from fruit processing industries were evaluated to understand its potential application as a functional food. Therefore, the bioactive compounds of pineapple by-products were characterized for prebiotic and antioxidant activities. A total characterization of soluble carbohydrates profile (simples and complex carbohydrates), as well as polyphenols was performed, after removal of enzymatic fraction from pineapple crude juice, allowing the decrease of proteolytic activity and improving the other biological activities. Results showed that pineapple liquid fraction, from stem and peels, can be applied as a prebiotic enhancer, promoting the growth of five probiotic microorganisms (two strains of Lactobacillus sp. and three strains of Bifidobacterium sp.), as a single carbohydrate source. Moreover, through HPLC (High Performance Liquid Chromatography) analysis, 10 polyphenols were identified in pineapple liquid fractions, with some expected differences between both evaluated by-products. Gastrointestinal tract was simulated, in a continuous mode to understand the impact of pH changes and gastrointestinal enzymes into pineapple liquid fractions. Results showed a digestion of high molecular weight polysaccharides into small molecular weight tri-, di-, and monosaccharides. There was an increase of samples antioxidant activity through the gastrointestinal stage, followed by the release of specific polyphenols, such as chlorogenic, coumaric, and ferulic acids. The prebiotic activity did not improve throughout the simulation, in fact, the prebiotic potential decreased throughout the different stages.
    2022-01-01Journal article Open access Show more
  • Impact of simulated in vitro gastrointestinal digestion on bioactive compounds, bioactivity and cytotoxicity of melon (Cucumis melo L. inodorus) peel juice powder
    Publication . Gómez-García, Ricardo; Vilas-Boas, Ana A.; Machado, Manuela; Campos, Débora A.; Aguilar, Cristóbal N.; Madureira, Ana R.; Pintado, Manuela
    The objectives of this research work were to evaluate the effect of in vitro gastrointestinal digestion (GIT) on melon peel juice (MPJ) powder from fruit processing industry by-products, considering (i) the recovery and accessibility indexes, (ii) the changes on antioxidant activity, and (iii) the prebiotic effect. Throughout exposition to GIT conditions a decrease on the total phenolic content (TPC = 65.31%) and antioxidant activity by ABTS = 39.77% and DPPH = 45.91% were observed. However, these both parameters exhibited stable accessibility, accounting with 81.89%, 76.55%, and 54.07% for TPC, ABTS and DPPH, respectively. After gastrointestinal digestion, the non-absorbed fraction exhibited a positive impact on the growth of Bifidobacterium and Lactobacillus strains, possibly associated with the high content of simple sugar (glucose and fructose). This fraction also showed to be safe on Caco-2 intestinal cells. These findings suggest that MPJ might be used as a potential food functional ingredient.
    2022-06Journal article Open access Show more
  • Innovative processing technologies to develop a new segment of functional citrus-based beverages: current and future trends
    Publication . Vilas-Boas, Ana A.; Magalhães, Daniela; Campos, Débora A.; Porretta, Sebastiano; Dellapina, Giovanna; Poli, Giovanna; Istanbullu, Yildiray; Demir, Sema; San Martín, Ángel Martínez; García-Gómez, Presentación; Mohammed, Reda S.; Ibrahim, Faten M.; El Habbasha, El Sayed; Pintado, Manuela
    The food industries are interested in developing functional products due to their popularity within nutritional and healthy circles. Functional fruit-based beverages represent one of the fast-growing markets due to the high concentrations of bioactive compounds (BCs), which can be health promoters. Hence, functional beverages based on citrus fruits are a potential way to take advantage of their nutritional and bioactive properties that could attract the interest of consumers. In order to ensure microbial and quality stability, the beverages are subjected to preservation treatment; however, the application of high temperatures leads to the loss of thermolabile BCs. Nowadays, innovative processing technologies (IPT) such as pulsed electric field (PEF), high-pressure processing (HPP), ultrasound processing (US), ohmic heating (OH), and microwave (MW) are a promising alternative due to their efficiency and low impact on juice BCs. The available literature concerning the effects of these technologies in functional fruit-based beverages is scarce; thus, this review gathers the most relevant information about the main positive and negative aspects of the IPT in functional properties, safety, and consumer acceptance of functional citrus-based beverages, as well as the use of citrus by-products to promote the circular economy in citrus processing.
    2022-12Journal article Open access Show more
  • Integrative and sustainable approach to obtain functional ingredients from orange by-products: case study on Algarve's citrus PGI
    Publication . Vilas-Boas, Ana A.; Campos, Débora A.; Correia, Marta; Pintado, Manuela
    2023-05-11Conference object Open access Show more