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- Ultralight microcellular polyurethanes for the production of technical footwear componentsPublication . Rafael, Helder Martins; Fernandes, Isabel P.; Gomes, Helder; Pinto, Vera; Fernandes, A.M.; Ferreira, Maria José; Barreiro, M.F.Today's society demands lightweight and comfortable footwear products, which represents a market opportunity for the footwear industry, motivating the development of new low-density (ultralight) materials. This research is dedicated to the development of ultralight microcellular polyurethanes (PUs) with suitable properties for the production of midsoles for technical footwear. In this context, the studies performed in this work aimed at reduce the density of microcellular PUs by the incorporation of additives based on expandable thermoplastic microspheres. Samples of a base formulation were modified by the incorporation of 1, 2 and 3% of the additive. The produced materials result in PUs with densities that varied from 0.45 to 0.30 g/cm3. The performed characterization pointed out for PUs with adequate technical properties, with particular emphasis for impact absorption, which evidenced the suitability of the developed materials for the production of midsoles for ultralight safety shoes.
- Functionalization of yogurts with Agaricus bisporus extracts encapsulated in spray-dried maltodextrin crosslinked with citric acidPublication . Francisco, Cristhian Rafael Lopes; Heleno, Sandrina A.; Fernandes, Isabel P.; Barreira, João C.M.; Calhelha, Ricardo C.; Barros, Lillian; Gonçalves, Odinei Hess; Ferreira, Isabel C.F.R.; Barreiro, M.F.Mushroom extracts contain bioactive compounds potentially useful to functionalize foodstuffs. Herein, alcoholic extracts of Agaricus bisporus were studied for their bioactivity and viability as functional ingredients in a food product with high water content (yogurt). Extracts were microencapsulated (to improve their stability and hydrophilicity) by spray-drying, using maltodextrin crosslinked with citric acid as encapsulating material. The effect of thermal treatment (after atomization) on crosslinking and bioactivity of microspheres was tested. The incorporation of free and thermally untreated forms resulted in yogurts with higher initial antioxidant activity (EC 50 values: 214 and 272 mg.mL −1 ) that decreased after 7 days (EC 50 values: 248 and 314 mg.mL −1 ). Contrarily, thermally treated microencapsulated extracts showed higher antioxidant activity after the same period (EC 50 values, 0 days: 106 mg.mL −1 ; 7 days: 48.7 mg.mL −1 ), in result of an effective protection provided by microencapsulation with crosslinked maltodextrin and citric acid. Functionalized yogurts showed an overall maintenance of nutritional properties.
- Valorization of lignin side-streams into polyols and rigid polyurethane foams—a contribution to the pulp and paper industry biorefineryPublication . Pinto, João A.; Fernandes, Isabel P.; Pinto, Virgínia; Gomes, Elson; Oliveira, Cátia F.; Pinto, Paula C.R.; Mesquita, L.M.R.; Piloto, P.A.G.; Rodrigues, Alírio; Barreiro, M.F.Valorization of industrial low-value side-streams are of great interest, contributing to boosts in the circular economy. In this context, lignin side-streams of the pulp and paper industry were oxypropylated to produce biobased polyols and tested in the synthesis of rigid polyurethane (RPU) foams. E. globulus lignins, namely a lignin isolated from an industrial Kraft black liquor and depolymerized lignins obtained as by-products of an oxidation process, were used. RPU foams, synthesized with 100% lignin-based polyols and using a 1.1 NCO/OH ratio, were characterized concerning apparent density, morphology, thermal conductivity, thermal stability, and heat release rate (HRR). Foams containing the lignin-based polyols presented densities varying from 44.7 to 112.2 kg/m3 and thermal conductivity in the range of 37.2–49.0 mW/mK. For the reference foam (sample produced with 100% wt. Daltofoam TP 32015 polyol), values of 70.9 kg/m3 and 41.1 mW/mK were obtained, respectively. The achieved results point out the viability of using the generated lignin-based polyols at 100% content in RPU foams, mainly when depolymerized lignins are used. Moreover, fire retardancy was favored when the lignin-based polyols were introduced. The proposed strategies can contribute to establishing the integrated pulp and paper biorefinery concept where material synthesis (polyols and RPU foams) can be combined with chemical production (vanillin and syringaldehyde).
- α-Tocopherol microencapsulation using chitosan and alginate: swelling behaviour under different pHPublication . Ribeiro, Andreia; Vieira, Dalila; Fernandes, Isabel P.; Amaral, Joana S.; Barreiro, M.F.Vitamin E is known for its antioxidant activity, particularly for its effective protection against lipid oxidation. The theory that reactive species, such as free radicals, may be involved in the development of degenerative processes associated with aging and cancer has led to a growing interest in the study of most antioxidants. In particular, Vitamin E is considered a lipophilic antioxidant, comprising a set of eight compounds (a-, p-, y-, 8-tocopherols and tocotrienols), of which α-tocopherol is the one presenting the highest capacity of free radicals uptake, in vitro. Due to α -tocopherol instability and sensitivity towards temperature re, oxygen and light, vitamin E supplements are generally administered in the most stable form of α-tocopherol acetate or succinate. However, these forms are considered to have a lower intestinal absorption.
- Scentfashion®: Microencapsulated perfumes for textile applicationPublication . Rodrigues, Sofia Nogueira; Martins, Isabel M.; Fernandes, Isabel P.; Gomes, P.B.; Mata, Vera G.; Barreiro, M.F.; Rodrigues, AlírioThis work is a contribution to the introduction of emergent technologies in the textile sector, namely the microencapsulation of fragrances and its application to obtain added-value products. Interfacial polymerization was used to produce polyurethane/urea (PUU) microcapsules with a perfume for industrial application on textile substrate having in view man suits production. The extent of reaction of PUU microcapsules formation was followed by Fourier transform infrared spectroscopy. Size distribution and morphology of the produced microcapsules were studied using particle size analysis, optical microscopy and scanning electron microscopy. Impregnation on textile substrates was tested both at laboratory level and at industrial scale. The fragrance release from textile substrates was measured with headspace chromatography. The content of microcapsules was released with light abrasion to simulate day-to-day wear, and fabrics impregnated at laboratory scale have survived to 9000 abrasion cycles. Microcapsules have continued to release aroma up to five dry cleaning washing cycles.
- Lipid composition optimization in spray congealing technique and testing with curcumin-loaded microparticlesPublication . Sorita, Guilherme Dallarmi; Santamaria-Echart, Arantzazu; Gozzo, Ângela Maria; Gonçalves, Odinei Hess; Leimann, Fernanda Vitória; Bona, Evandro; Manrique, Yaidelin A.; Fernandes, Isabel P.; Ferreira, Isabel C.F.R.; Barreiro, M.F.Spray-congealing, a technique based on the fast solidification of sprayed molten lipids, is considered a novel strategy to encapsulate natural products. Among others, it is a safe, low cost, fast and reproducible technique, with rising interest for several applications (e.g. food applications). One of the key parameters for the application of this technique is the lipid solidification temperature, which can be modulated by optimizing the lipid composition. In this work, three lipid components (beeswax, carnauba wax, and medium-chain triglycerides (Miglyol 812)) were selected, and the mixture composition modelled using a simplex-centroid experimental design. Three different lipid compositions were chosen to validate the proposed model, then tested in the preparation of curcumin-loaded microparticles (1.5%, w/w). The produced microparticles were analysed in terms of colour, morphology, particle size, encapsulation efficiency and load, physicochemical, crystalline, and thermal properties. Results evidenced that microparticle's properties, including encapsulation efficiency, vary according to the used lipid mixture, supporting their tailoring role. This fact brings advantages in the design of microencapsulation systems based on spray congealing processes, broadening their applicability. Moreover, lipid composition optimisation was proved to be an important tool to precede the development of spray-congealing applications.
- Fungal degradation of lignin-based rigid polyurethane foamsPublication . Amaral, Joana S.; Sepúlveda, Manuel Martinho Vilas Boas; Cateto, Carolina; Fernandes, Isabel P.; Rodrigues, Alírio; Belgacem, Mohamed Naceur; Barreiro, M.F.In this work, the ability of Aspergillus niger to degrade two lignin-based rigid polyurethane (RPU) foams was evaluated and compared with a control RPU foam based on a commercial polyether-polyol, Lupranol 3323. The foams degradation was studied according to different procedures, namely by setting different series of batch cultures, either using liquid media or soil conditions, for 90 days at 30 C. For the soil conditions, two different assays were performed, namely with and without A. niger addition. The changes in the morphology of the RPU foams were evaluated by optical (OM) and scanning electron microscopy (SEM), whereas the structural modifications were inspected by FTIR spectroscopy. After 90 days treatment, morphological changes were clearly visible at the surface (cell wall) of the two lignin-based foams indicating a stronger effect of the microorganisms’ activity in these samples. FTIR spectra confirmed that the chemical structure of the polymer suffered modifications after the respirometry assays due to microorganisms attack. Comparatively to the commercial foam, it was observed that both the lignin-based foams presented a higher degradation level.
- Sitting time and body mass índex in a sample of portuguese university studentsPublication . Vasconcelos, Carlos; Fernandes, José Carlos; Fernandes, Isabel P.; Fernandes, Bóris dos Santos; Rocha, Carina; Sá, CarlaINTRODUCTION: Overweight and obesity are serious health problems in Portugal, with physical, psychological and social consequences that affects individuals’ quality of life. In university students’ daily routine, sitting is a predominant behavior for many hours per day, increasing sedentary time among these individuals. OBJECTIVES: The purpose of this study was to analyze the association between the time spent sitting in an ordinary weekday and body mass index in a sample of Portuguese university students. METHODOLOGY: This was a cross-sectional study performed in 72 Portuguese university students (38 female; 22.1 ± 3.9 years of age). The time spent sitting in an ordinary weekday was assessed with the International Physical Activity Questionnaire (short last week version). Body mass index was calculated through self-reported body weight (kg) and body height (m) data with the formula body weight (kg) / body height (m)2. RESULTS: The time spent sitting in an ordinary weekday was 342.1 ± 192.7 minutes. The mean value of body mass index was 22.9 ± 2.9 kg/m2. Through the use of Pearson correlation, we determine that the association between sitting time and body mass index is positive and significant (r = 0.511; p < 0.001). CONCLUSIONS: Our study revealed that there was significant association between sitting time and body mass index in this sample of Portuguese university students. Although the cross sectional design of our study do not allow to establish causality, it suggests the need of effective strategies to reduce time sitting in this individuals.
- Microencapsulation of Ceratonia siliqua L. extract for food purposes: effect of extract/alginate ratioPublication . Rached, Irada; Fernandes, Isabel P.; Barros, Lillian; Rodrigues, Alírio; Ferchichi, Ali; Ferreira, Isabel C.F.R.; Barreiro, M.F.Human health, nutritional status and well being can be enhanced through consumption of foods containing specifically desired nutrients and bioactive agents [1]. Popularly known as St John’s Bread, Ceratonia siliqua L. (carob) has a long history of use in food (over 4000 years). It has a good nutritional value and its polyphenolic extract shows high antioxidant capacity and even higher antiradical activity than well-aged red wines. Its reducing power can also be four-fold higher than many well known potent antioxidant agents such as gallic acid, caffeic acid and catechin [2]. Nevertheless, preparing high quality nutritious food is critically dependent on availability of effective delivery systems. Such systems should preserve the specific nutritional, biological, chemical and functional properties of the sensitive constituent, and should effectively release the compounds, in a desired mode, after ingestion. Nowadays, the most promising technology that can allow overcoming the stated difficulties is microencapsulation [1]. In this context, a hydroethanolic (80:20, v/v) extract obtained from carob pulp by ultrasound extraction was microencapsulated for further use in the development of functional yogurts.
- Phenolic extracts of Rubus ulmifolius Schoot flowers: characterization, microencapsulation and incorporation into yogurts as nutraceutical sourcesPublication . Martins, Ana; Barros, Lillian; Carvalho, Ana Maria; Santos-Buelga, Celestino; Fernandes, Isabel P.; Barreiro, M.F.; Ferreira, Isabel C.F.R.Rubus ulmifolius Schott (Rosaceae), known as wild blackberry, is a perennial shrub found in wild and cultivated habitats in Europe, Asia and North Africa. Traditionally, it is used for homemade remedies because of its medicinal properties, including antioxidant activity. In the present work, phenolic extracts of R. ulmifolius flower buds obtained by decoction and hydroalcoholic extraction were chemically and biologically characterized. Several phenolic compounds were identified in both decoction and hydroalcoholic extracts of flowers, ellagitannin derivatives being the most abundant ones, namely the sanguiin H-10 isomer and lambertianin. Additionally, comparing with the decoction form, the hydroalcoholic extract presented both higher phenolic content and antioxidant activity. The hydroalcoholic extract was thereafter microencapsulated in an alginate-based matrix and incorporated into a yogurt to achieve antioxidant benefits. In what concerns the performed incorporation tests, the obtained results pointed out that, among the tested samples, the yoghurt containing the microencapsulated extract presented a slightly higher antioxidant activity, and that both forms (free and microencapsulated extracts) gave rise to products with higher activity than the control. In conclusion, this study demonstrated the antioxidant potential of the R. ulmifolius hydroalcoholic extract and the effectiveness of the microencapsulation technique used for its preservation, thus opening new prospects for the exploitation of these natural phenolic extracts in food applications