Browsing by Author "Madureira, Ana R."
Now showing 1 - 10 of 10
Results Per Page
Sort Options
- 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.
- Biological protein precipitation: a green process for the extraction of cucumisin from melon (Cucumis melo L. inodorus) by-productsPublication . Gómez-García, Ricardo; Campos, Débora A.; Aguilar, Cristóbal N.; Madureira, Ana R.; Pintado, ManuelaCucumisin (CUC) from industrial melon by-products was separated for the first time through biological precipitation using carrageenan (CRG). This approach could represent a cost-effective and environmentally friendly process for the industries, avoiding the use of expensive equipment and toxic salts or solvents, such as butanol and ethanol. In this study, biological precipitation of proteins from melon by-products using CRG was studied and compared with conventional precipitation with ammonium sulphate. Different methods were applied for the identification and characterization of isolated proteins, including SDS-PAGE gel, FPLC and proteolytic activity assays. The isolated CUC confirmed a molecular weight of 68 kDa and showed highly stable proteolytic (PA) and milk-clotting (MCA) activities in a wide range of CaCl2 (20 to 60 mM), pH (5 to 7) and temperatures (30 to 85 ºC). Melon peel extract demonstrated to possess significant PA (4.24 U/mg protein) and MCA (191.50 MCU/mg protein), but such values were increased by ammonium sulphate precipitation (1.60 and 2.06-folds, respectively), and specially a noticeable increment was observed by biological precipitation with 2.11 and 17.65-folds, respectively, demonstrating the capability to be an effective strategy to isolate and purify CUC, allowing a yield of 0.17 g CUC/100 g of by-products and keeping its biological properties.
- Bovine whey proteins - overview on their main biological propertiesPublication . Madureira, Ana R.; Pereira, Cláudia I.; Gomes, Ana M. P.; Pintado, M. E.; Malcata, F. XavierWhey, a liquid by-product, is widely accepted to contain many valuable constituents. These include especially proteins that posses important nutritional and biological properties – particularly with regard to promotion of health, as well as prevention of diseases and health conditions. Antimicrobial and antiviral actions, immune system stimulation, anticarcinogenic activity and other metabolic features have indeed been associated with such whey proteins, as a-lactalbumin, b-lactoglobulin, lactoferrin, lactoperoxidase, and bovine serum albumin. The most important advances reported to date pertaining to biological properties of whey proteins are reviewed in this communication.
- A chemical valorisation of melon peels towards functional food ingredients: bioactives profile and antioxidant propertiesPublication . Gómez-García, Ricardo; Campos, Débora A.; Oliveira, Ana; Aguilar, Cristóbal N.; Madureira, Ana R.; Pintado, ManuelaThe goal of this work was to characterize the profile of bioactive compounds and the antioxidant activity of inodorus melon peels. Melon peels were divided into three fractions: a solid fraction with a higher content of carbohydrates (84.81%); a liquid fraction with a higher ash content (11.5%); and a pellet fraction with a higher protein content (34.90%). The structural carbohydrates study revealed a composition of cellulose (27.68%), hemicellulose (8.2%) and lignin (26.46%) in the solid fraction. The liquid fraction had the highest antioxidant activity based on results from DPPH, ABTS and ORAC assays. Flavones, hydroxybenzoic and hydroxycinnamic acids were the main phenolic classes found in all fractions. In addition, β-carotene, lutein, β-cryptoxanthin and violaxanthin had also been quantified. Melon fractions were rich in nutrients and bioactive substances and could be useful in the development of novel functional products, considering the growing market demand for safe and healthy food products.
- Effect of in vitro digestion upon the antioxidant capacity of aqueous extracts of Agrimonia eupatoria, Rubus idaeus, Salvia sp. and Satureja montanaPublication . Gião, Maria S.; Gomes, Susana; Madureira, Ana R.; Faria, Ana; Pestana, Diogo; Calhau, Conceição; Pintado, Manuela E.; Azevedo, Isabel; Malcata, F. XavierAn in vitro digestion/Caco-2 cell culture model was used to assess the stability and bioavailability of phenolic compounds in aqueous extracts of four herbal infusions, traditionally used as functional drinks in Portugal. Alterations in antioxidant power were monitored by ABTS +, whereas the profile of phenolic compounds was ascertained by HPLC-DAD. The bioavailability of rutin – an important flavonoid present in such extracts, and thus a representative of those compounds, was assessed across Caco-2 cells via LC– MS/MS. Our results indicate that several antioxidant compounds are not affected by the (simulated) digestive process, whereas others undergo decreases in their activity throughout said process; a few have their antioxidant capacity hampered under stomach-like conditions. It was also found that rutin can be transported across the Caco-2 cell barrier.
- Impact of simulated in vitro gastrointestinal digestion on bioactive compounds, bioactivity and cytotoxicity of melon (Cucumis melo L. inodorus) peel juice powderPublication . Gómez-García, Ricardo; Vilas-Boas, Ana A.; Machado, Manuela; Campos, Débora A.; Aguilar, Cristóbal N.; Madureira, Ana R.; Pintado, ManuelaThe 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.
- Incorporation and survival of probiotic bacteria in whey cheese matricesPublication . Madureira, Ana R.; Gião, Maria S.; Pintado, Manuela E.; Gomes, Ana M. P.; Freitas, A. Cristina; Malcata, F. XavierThe viabilities of probiotic strains of Lactobacillus acidophilus, Lactobacillus paracasei, Bifidobacterium animalis, and Lactobacillus brevis were studied following incorporation in a whey cheese matrix. Experimental production of plain, as well as sugar-added or salt-added whey cheeses, was based on the traditional manufacture protocol of Requeijäo, a Portuguese whey cheese that essentially results from protein denaturation via heating of whey at about 85°C. After inoculation, the experimental whey cheeses were incubated at 7°C for 28 d. Our results have shown that all strains considered were able to maintain (or even increase) their initial viable numbers; L. paracasei ssp. paracasei strain LCS-1 and L. acidophilus strain Ki exhibited the highest cell viability in plain Requeijão by the end of the storage period—an increase of ca. 2 log cycles in their viable numbers was actually recorded. Among the parameters studied, bacterial species and matrix nature had the most important effect upon viable counts, whereas time of storage was the least important.
- Obtention and characterization of microcrystalline cellulose from industrial melon residues following a biorefinery approachPublication . Gómez-García, Ricardo; Sousa, Sérgio C.; Ramos, Óscar L.; Campos, Débora A.; Aguilar, Cristóbal N.; Madureira, Ana R.; Pintado, ManuelaResidual melon by-products were explored for the first time as a bioresource of microcrystalline cellulose (MCC) obtention. Two alkaline extraction methods were employed, the traditional (4.5% NaOH, 2 h, 80 °C) and a thermo-alkaline in the autoclave (2% NaOH, 1 h, 100 °C), obtaining a yield of MCC ranging from 4.76 to 9.15% and 2.32 to 3.29%, respectively. The final MCCs were characterized for their chemical groups by Fourier-transform infrared spectroscopy (FTIR), crystallinity with X-ray diffraction, and morphology analyzed by scanning electron microscope (SEM). FTIR spectra showed that the traditional protocol allows for a more effective hemicellulose and lignin removal from the melon residues than the thermo-alkaline process. The degree of crystallinity of MCC ranged from 51.51 to 61.94% and 54.80 to 55.07% for the thermo-alkaline and traditional processes, respectively. The peaks detected in X-ray diffraction patterns indicated the presence of Type I cellulose. SEM analysis revealed microcrystals with rough surfaces and great porosity, which could remark their high-water absorption capacity and drug-carrier capacities. Thus, these findings could respond to the need to valorize industrial melon by-products as raw materials for MCC obtention with potential applications as biodegradable materials.
- Technological optimization of manufacture of probiotic whey cheese matricesPublication . Madureira, Ana R.; Brandão, Teresa R. S.; Gomes, Ana M.; Pintado, Manuela E.; Malcata, F. XavierIn attempts to optimize their manufacture, whey cheese matrices obtained via thermal processing of whey (leading to protein precipitation) and inoculated with probiotic cultures were tested. A central composite, face-centered design was followed, so a total of 16 experiments were run using fractional addition of bovine milk to feedstock whey, homogenization time, and storage time of whey cheese as processing parameters. Probiotic whey cheese matrices were inoculated with Lactobacillus casei LAFTIR L26 at 10% (v/v), whereas control whey cheese matrices were added with skim milk previously acidified with lactic acid to the same level. All whey cheeses were stored at 7 ◦C up to 14 d. Chemical and sensory analyses were carried out for all samples, as well as rheological characterization by oscillatory viscometry and textural profiling. As expected, differences were found between control and probiotic matrices: fractional addition of milk and storage time were the factors accounting for the most important effects. Estimation of the best operating parameters was via response surface analysis: milk addition at a rate of 10% to 15% (v/v), and homogenization for 5 min led to the best probiotic whey cheeses in terms of texture and organoleptic properties, whereas the best time for consumption was found to be by 9 d of storage following manufacture.
- Valorization of melon fruit (Cucumis melo L.) by-products: phytochemical and biofunctional properties with emphasis on recent trends and advancesPublication . Gómez-García, Ricardo; Campos, Débora A.; Aguilar, Cristobal N.; Madureira, Ana R.; Pintado, ManuelaBackground: For modern food industry, sustainability of food processing is a major concern coupled to the reduction of waste generation. Fruit and vegetable processing require of modernization to valorize the waste and by-products highly generated, particularly because they are rich in natural beneficial components which are demanded to human health. Melon (Cucumis melo L.) processing generate a high amount of peels and seeds, which are recognized with higher content of bioactive compounds than pulp, including polyphenols, carotenoids and oils. Scope and approach: In this review, we summarize information about of the bioactive compounds present in the melon fruit, together with the nutritionals properties that it presents as a functional food, with a focus on its by-products (pulp, seed and peel). The melon fruit contains important bioactive compounds, mainly the peel has a high content of antioxidants which are of interest in the food, cosmetic and pharmaceutical industries. These findings pretend to support new research concerning the formulation of novel functional foods based on melon by-products. Key finding and conclusions: Extracts of melon fruit, mainly from the peel, have been shown to possess phytochemical compounds that exhibit antioxidant, antimicrobial, antidiabetic, antiviral, anti-inflammatory, anti-hypoglycemia and anti-proliferative effects in various in vitro and in vivo test. However, it is necessary for further analyze the nutritional and functional potential of these by-products, the therapeutic and clinic mechanisms involved and to develop its industrial process as functional or nutraceutical food products.