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- Conservation of wild mushrooms through electron beam irradiationPublication . Fernandes, Ângela; Antonio, Amilcar L.; Rafalski, Andrzej; Barreira, João C.M.; Oliveira, Beatriz; Martins, Anabela; Ferreira, Isabel C.F.R.The high perishability is a characteristic of the mushrooms consumed in fresh. Therefore, it is mandatory the application of effective conservation technologies to preserve and protect their chemical composition and nutritional value. Drying processes are widely used, but do not avoid the development of bacteria and fungi which have the ability to survive for long periods of time in dry foods, causing the loss of some nutrients and leading to food browning and oxidation of lipids and vitamins [1]. Irradiation appears as an alternative to food preservation assuring and maintaining its quality [2]. In this work, the effects of electron beam irradiation and storage time on nutritional and chemical parameters of wild samples of Macrolepiota procera (Scop.) Singer, previously submitted to a drying process (oven at 30 ºC), were assessed. The wild mushroom samples were collected in Trás-os-Montes; electron beam irradiation (doses 0.5, 1 and 6 kGy) was carried out in the INCT- Institute of Nuclear Chemistry and Technology in Warsaw, Poland and the analyses were performed over the storage period (0, 6 and 12 months). The results were compared with a control (non-irradiated samples). The nutritional value was determined according to the official procedures of food analysis, while the profiles of fatty acids, tocopherols, mono and oligosaccharides were obtained by chromatographic techniques [1]. The irradiation showed a better capacity to maintain the nutritional and chemical profile, in comparison with the storage time. Effectively, the storage time had a significant effect in all parameters, but fatty acids undergone significant changes both with irradiation doses and storage time. Electron beam irradiation can be considered a suitable technique for conservation of mushrooms for long periods of time, attenuating the changes caused by the drying treatment.
- Evaluation of the chemical interactions in co-culture elements of Castanea sativa Miller mycorrhizationPublication . Carvalho, Filipa Arminda; Ferreira, Isabel C.F.R.; Barreira, João C.M.; Barros, Lillian; Martins, AnabelaIn the early steps of mycorrhizal associations an oxidative burst might occur through the rapid production of high amounts of reactive oxygen species in response to external stimuli, increasing the production of antioxidants in plant and/or mycelia. Herein, the effect of mycorrhizal association among Pisolithus arhizus or Paxillus involutus and Castanea sativa Miller (stems and roots) was studied for different co-culture periods, defined for a better comprehension of the chemical interactions in the early stages of mycorrhization (6, 24 and 72 h). Knowledge on the specificities of plant-host interaction provided information about the most suitable fungus to be included in the development of new management strategies, and the fungal species that induced the strongest response with increasing antioxidant activity (free radical scavenging activity, reducing power and lipid peroxidation inhibition) and production of antioxidant compounds (phenolics and tocopherols) and sugars. P. involutus seemed to be the most adequate fungus to mycorrhize with C. sativa. Considering bioactive compounds production, P. arhizus was more efficient since allowed an increase in the contents of sugars and tocopherols in all co-culture elements.
- Chemical composition of Boletus pinophilus and Clitocybe subconnexa: preservation with gamma irradiationPublication . Fernandes, Ângela; Antonio, Amilcar L.; Barreira, João C.M.; Martins, Anabela; Oliveira, Beatriz; Ferreira, Isabel C.F.R.The short shelf life of mushrooms is a barrier for their distribution and, therefore, there has been extensive research to find technologies that ensure the preservation of mushrooms, maintaining their organoleptic and nutritional properties (1]. Irradiation has proved its technological feasibility to be safely used in the reduction of food losses, being recognized by international organizations as a valid conservation alternative in extending shelflife of many foods. The aim of the present work was to validate the use of 2 kGy dose of gamma radiation to maintain chemical composition of wild mushrooms. Boletus pinophilus Pihit & Dermek and Clitocybe subconnexa Murrill wild samples were obtained in Tnis-os-Montes; subsequently, the samples were divided in two groups: control (non-irradiated, 0 kGy) and irradiated (2 kGy). The irradiation of the samples was performed in a 6°Co experimental chamber. Moisture, protein, fat, carbohydrates and ash were determined following the standard procedures [2]. Free sugars and tocopherols were determined by high performance liquid chromatography coupled to a refraction index detector (HPLC-RI) and a fluorescence detector, respectively; fatty acids were determined by gas-liquid chromatography with flame ionization detection (GC-FID) [3]. The protein and ash content was preserved in both groups, although the sugars and tocopherols decreased in the irradiated samples. Sugars and fatty acids showed significant changes after irradiation treatment, particularly in B. pinophillus, nevertheless, the magnitude of the obtained differences did not seem to be sufficient to affect the chemical profiles of the assayed mushrooms. Overall, the detected chemical changes might be considered as allowable, in view of the high advantages offered by gamma irradiation at decontamination and/or disinfestation level.
- Insights on the formulation of herbal beverages with medicinal claims according with their antioxidant propertiesPublication . Barreira, João C.M.; Morais, Ana L.; Ferreira, Isabel C.F.R.; Oliveira, BeatrizSeveral herbal beverages claim medicinal benefits due to their antioxidant properties. However, operational factors such as the extracted herbal component, preparation method or concentration levels, might influence their biological activity. To assess this effect, the antioxidant activity of beverages prepared with Camellia sinensis, Aspalathus linearis or Cochlospermum angolensis, used solely or mixed with different fruit, plant or algae extracts, was studied using different formulations (bags, leaves, roots, granulates, powders, liquids) and different preparation methods (infusion, solubilisation or promptly used). The DF50 (dilution factor responsible for 50% of antioxidant activity) values were calculated to compare their antioxidant activity. A linear discriminant analysis was used to categorize the assayed samples according to their antioxidant activity and bioactive molecules profiles. The results indicated that antioxidant activity and antioxidant compounds are significantly affected by formulation and preparation method, but overall the labelled antioxidant benefits were validated. Green tea showed the highest activity, but with different behaviour within each used formulation. The high DF50 values calculated for some products might be used to adjust the dietary dose or formulation, preventing also putative pro-oxidant effects. Hence, the obtained results might be useful to define the formulation of these highly consumed herbal beverages, enhancing their health effects.
- 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.
- Antioxidant activity of portuguese honey samples: different contribution of the entire honey and phenolic extractPublication . Ferreira, Isabel C.F.R.; Aires, Edmur; Barreira, João C.M.; Estevinho, Leticia M.The antioxidant activity of Portuguese honeys was evaluated considering the different contribution of entire samples and phenolic extracts. Several chemical and biochemical assays were used to screen the antioxidant properties of entire honeys with different colour intensity and phenolic extracts: reducing power, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging capacity, and inhibition of lipid peroxidation using the b-carotene linoleate model system and the thiobarbituric acid reactive substances (TBARS) assay. The amounts of phenols, flavonoids, ascorbic acid, b-carotene, lycopene and sugars present in the samples were also determined. The highest antioxidant contents and the lowest EC50 values for antioxidant activity were obtained in the dark honey. An analysis of variance was carried out to evaluate the influence of the colour intensity and extraction method in the antioxidant properties and phenolic contents. A discriminant analysis was also performed, giving satisfactory results once the six samples were clustered in six individual groups obtained through the definition of two discriminant analysis dimensions.
- Bioactivity, proximate, mineral and volatile profiles along the flowering stages of Opuntia microdasys (Lehm.): defining potential applicationsPublication . Chahdoura, Hassiba; Barreira, João C.M.; Fernández-Ruiz, Virginia; Morales, Patricia; Calhelha, Ricardo C.; Flamini, Guido; Soković, Marina; Ferreira, Isabel C.F.R.; Achour, LotfiOpuntia spp. flowers have been traditionally used for medical purposes, mostly because of their diversity in bioactive molecules with health promoting properties. The proximate, mineral and volatile compound profiles, together with the cytotoxic and antimicrobial properties were characterized in O. microdasys flowers at different maturity stages, revealing several statistically significant differences. O. microdasys stood out mainly for its high contents of dietary fiber, potassium and camphor, and its high activities against HCT15 cells, Staphylococcus aureus, Aspergillus versicolor and Penicillium funiculosum. The vegetative stage showed the highest cytotoxic and antifungal activities, whilst the full flowering stage was particularly active against bacterial species. The complete dataset has been classified by principal component analysis, achieving clearly identifiable groups for each flowering stage, elucidating also the most distinctive features, and comprehensively profiling each of the assayed stages. The results might be useful to define the best flowering stage considering practical application purposes.
- Propriedades bioativas de formulações hidrofílicas de curcumina: aplicação em iogurtePublication . Leimann, Fernanda Vitória; Almeida, Heloísa H.S.; Roriz, Custódio Lobo; Barros, Lillian; Barreira, João C.M.; Calhelha, Ricardo C.; Barreiro, M.F.; Ferreira, Isabel C.F.R.A curcumina tem reconhecidas propriedades bioativas e corantes. Porém, a sua aplicação em produtos alimentares é dificultada pela sua baixa solubilidade em meios hidrofílicos. De forma a ultrapassar esta limitação, foram preparadas nanopartículas de poli(vinil-pirrolidona) (PVP, 40.000g/mol)/curcumina com base na técnica de dispersão sólida, utilizando Tween 80 como estabilizante e etanol como solvente. As nanopartículas foram caracterizadas quanto à morfologia (microscopia eletrónica de transmissão) indicando forma esférica e tamanho (dispersão dinâmica de luz) com índice de polidispersão = 0,050±0,009 e diâmetro médio em intensidade = 377±15 nm. As propriedades térmicas (análise termogravimétrica, TG), interações químicas (Espectroscopia de Infravermelho com Transformada de Fourier, FTIR). As análises por TG revelaram que as nanopartículas não apresentaram perda de humidade (não se observou nenhuma transição antes dos 100 ºC), justificada pelo facto de os pontos de ligação da PVP à água terem dado origem a interações com a curcumina na sequência da encapsulação [1]. A análise por FTIR comprovou este facto dado a ausência da banda característica a 3510 cm-1 na zona do estiramento dos OHs. As propriedades bioativas (atividade antioxidante, atividade anti-inflamatória e citotoxicidade) das nanopartículas de PVP/curcumina (NC) foram comparadas às da curcumina pura utilizada no procedimento de nanoencapsulação (PC) (Sigma Aldrich) e às de uma amostra comercial dispersável (DC) (CHR Hansen, Vegex Tumeric WS5). Os valores de EC50 (μg/mL) para a atividade antioxidante (DPPH, poder redutor, β-caroteno e TBARS) evidenciaram o seguinte perfil de atividade: PC>NC>DC, similarmente à resposta anti-inflamatória (concentração responsável por 50% da inibição da produção de óxido nítrico em comparação com o controlo negativo). Quanto à citotoxicidade, a PC revelou uma atividade superior em todas as linhas celulares, tendo os valores de GI50 (μg/mL) indicado atividade NC>DC apenas nos casos das linhas HeLa, HepG2 e PLP2 e indistinta nas MCF-7 e NCI-H460. Na etapa seguinte, as formulações PC, NC e DC foram aplicadas em iogurtes, para os quais se avaliou o perfil nutricional (humidade, cinzas, gordura, proteínas, hidratos de carbono e energia) e os parâmetros de cor (L*, a* e b*) ao longo do tempo de armazenamento (TA = 0, 7 e 15 dias, 4 ºC). Independentemente de TA, os iogurtes com DC apresentaram os teores de cinza, gordura, energia e L* superiores, enquanto os valores a* e b* foram superiores para os com PC. O teor máximo de proteína foi registado para os iogurtes com NC e o teor máximo de hidratos de carbono para as amostras controlo. Quanto a TA, as amostras armazenadas durante 7 dias caracterizaram-se por teores superiores de proteína, cinza (tal como as amostras armazenadas durante 15 dias), hidratos de carbono e energia, enquanto as amostras analisadas no dia de preparação registaram os valores mais elevados para gordura e a*. O efeito do tempo de armazenamento não foi significativo nos parâmetros L* e b*. Em síntese, e apesar de se terem observado algumas diferenças significativas nos indicadores nutricionais e parâmetros de cor, pode concluir-se que as nanopartículas de PVP/curcumina são uma boa estratégia para coloração do iogurte, não se tendo registado sem alterações relevantes do seu valor nutricional e aparência. Adicionalmente, e dado a bioatividade evidenciada, a sua utilização resultará em benefícios adicionais não conseguidos com a PC (baixa solubilidade em meio hidrofílico).
- Effects of gamma irradiation on sugars, fatty acids and tocopherols of chestnuts (Castanea sativa Miller)Publication . Barros, Lillian; Antonio, Amilcar L.; Barreira, João C.M.; Fernandes, Ângela; Bento, Albino; Botelho, M. Luísa; Ferreira, Isabel C.F.R.As seasonal products chestnuts have to be postharvest treated to increase their shelf-life. The most common preservation method for chestnuts is the use of chemical fumigation with methyl bromide, a toxic agent that is under strictly use under Montreal Protocol due to its adverse effects on human health and environment. Food irradiation is a possible feasible alternative to substitute the traditional quarantine chemical fumigation treatment. The main studies in chestnuts irradiation were done in an Asian variety, which is bigger and sweeter than the European types. However, on Portuguese varieties nothing has been reported. Herein, the influence of irradiation and storage time in sugars, fatty acids and tocopherols profiles/quantities in chestnuts obtained in Trás-os-Montes, Northeast Portugal, was evaluated for the fist time.
- Bioactivity, hydrophilic, lipophilic and volatile compounds in pulps and skins of Opuntia macrorhiza and Opuntia microdasys fruitsPublication . Chahdoura, Hassiba; Barreira, João C.M.; Barros, Lillian; Dias, Maria Inês; Calhelha, Ricardo C.; Flamini, Guido; Soković, Marina; Achour, Lotfi; Ferreira, Isabel C.F.R.Opuntia genus includes several species able to grow in arid regions and known for producing delicate fruits, which are far from being thoroughly characterized. Herein, fruits from O. macrorhiza and O. microdasys were divided in skins and pulps (without including seeds) and studied for chemical composition, individual phytochemicals and bioactivity. The major volatiles were camphor and ethyl acetate, while citric acid was the main organic acid. The fatty acids detected in highest percentages were linoleic acid (skins) and lauric acid (pulps); α- tocopherol was the major isoform of vitamin E. Quercetin-3-O-rutinoside and quercetin-O-(deoxyhexoside-rutinoside) were the main phenolics in fruit skins of O. macrorhiza and O. microdasys (respectively), similarly to piscidic acid in O. macrorhiza pulp (O. microdasys pulp showed no quantifiable compounds). Betanin and isobetanin were the major betalains. All samples were antioxidant (particularly O. macrorhiza), but antimicrobial activity was only detected in skins. Cytotoxicity was low in all cases. Overall, these fruits proved to be potential new ingredients for food or pharmaceutical related applications, adding value to these natural species able to grow in arid environments.