DAN - Apresentações orais em encontros internacionais
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- Abundance of Selenium and Selenoproteins in foods consumed in PortugalPublication . Gueifão, Sandra; Sanches, Diana; Delgado, Inês; Coelho, Inês; Ventura, Marta; Castanheira, IsabelSelenium (Se) is an essential element for human health. Dietary levels in the population are positively correlated to selenium content in foods as consumed. Dietary Reference Intake for Se is 55 μg/day for adult men and women. However, depending on the species, oxidation state and concentration Se can be toxic to human health. Accurate determination of Se content in the diet demands information not only on total Se (tSe) but also on the bioaccessible species presented in food samples [1]. The aim of this work was to evaluate the concentration of tSe and Se species as Selenomethionine (SeMet), Selenite (SeIV) and Selenate (SeVI) in cow milk, cabbage and fish samples consumed in Portugal. Accurate analysis of tSe was carried out by ICP-MS preceded by acid digestion in a closed-vessel microwave system. Several approaches for extraction of Se species from food matrices were studied followed by quantification with HPLC-ICP-MS. The reliable conditions of analytical procedures were achieved with metrological tools operated under the frame of ISO/EN 17025:2005. tSe content ranged from 67 ± 3 ug.kg-1 (cabbage), 161 ± 16 ug.kg-1 (milk) and 988 ± 27 ug.kg-1 (fish). SeMet was major selenium species in milk and fish samples accounting for 85 -90 % of tSe content. In cabbage Se (IV), Se (VI) and (SeMet) were found. The results showed the suitability of analytical procedure to measure tSe and seemed effective to achieve an accurate determination of Se species in these complex matrices. References: [1] Bodnar, M., Szczyglowska, M., Konieczka, P., Namiesnik, J. Methods of Selenium Supplementation: Bioavailability and Determination of Selenium Compounds. Critical Reviews in Food Science and Nutrition. 2016. 56: 36-55.
- Active Packaging: application of natural antioxidantsPublication . Sanches-Silva, Ana; Costa, Denise; Albuquerque, T.G.; Castilho, Maria Conceição; Ramos, Fernando; Machado, Ana V.; Costa, H.S.Natural antioxidants applied in Active food Packaging: Food oxidation; Antioxidants; Food Packaging; Active Packaging; Legislation; Natural antioxidants.
- Active polylactic acid film incorporated with green tea extractPublication . Vilarinho, FernandaThe goal of this work was to produce a biodegradable active film based on polylactic acid (PLA) in which green tea extract (GTE) has been immobilized by extrusion, Two GTE concentrations were tested, 1% (w/w) and 2% (w/w). Four different GTEs were characterized regarding its antioxidant capacity, total phenolics content (TPC) and total flavonoids content (TFC). The commercial GTE chosen presented with highest antioxidant capacity by the DPPH radical assay (EC50= 0.12 ± 0.00 mg/mL) and highest TPC (416 ± 9.95 mg gallic acid equivalents (GAE)/g extract) being selected to be incorporated in the active film. The new film was to evaluated regarding its mechanical properties (e.g. tensile strength decreased 12% with the incorporation of GTE in the PLA matrix and strain at break increased 9.6% and 36% with the addition of 1% and 2% of GTE, respectively), water vapour transmission rate (water-vapour barrier properties improved with the addition of higher amounts of GTE) and effectiveness to inhibit lipid oxidation of model food. Smoked salmon was selected due to be a much appreciated high-fat content food with considerable high value in the market. The methods applied were: peroxide value, p-anisidine value, thiobarbituric acid reactive substances (TBARS) assay and hexanal monitoring, after packaging smoked salmon slices during different storage times (0, 7, 15, 30, 45 and 60 days). According to the results, the incorporation of GTE in the PLA films protects the smoked salmon from lipid oxidation in the different storage times tested. However, further studies should be performed to better understand the GTE mechanism of action as the results indicate a pro-oxidant effect of PLA/GTE 2% after 60 days of storage and to evaluate the potential antimicrobial activity of active films. To our information, this is the first time that an active PLA film containing GTE is evaluated regarding mechanical and barrier properties as well as its effectiveness in inhibiting lipid oxidation of smoked salmon.
- Aflatoxin exposure through food consumption – are we ready to face the risk associated to climate change?Publication . Assunção, Ricardo; Alvito, Paula; Jakobsen, Lea; Pires, S.Climate change (CC) has been indicated as a driver for food safety issues worldwide, mainly due to the impact on the occurrence of food safety hazards at various stages of food chain. Mycotoxins, natural contaminants produced by fungi, are mentioned to be one of the most important food safety hazards affected by CC. Aflatoxins, which have the highest acute and chronic toxicity of all mycotoxins, assumes particular importance within this context. A recent study predicted aflatoxin contamination in maize and wheat crops in Europe within the next 100 years. The authors concluded that aflatoxin B1 (AFB1) is predicted to become a food safety issue in Europe, especially in the +2 °C scenario, the most probable scenario of CC expected for the next years. In Europe, previous reported studies estimated mean dietary exposures to aflatoxins for the general population from all food sources ranging from 0.93 ng kg bw-1 day-1 to 2.4 ng kg bw-1 day-1. In Portugal, an estimation of a probable daily exposure to aflatoxins of 0.501 ng kg bw-1 day-1 by the Portuguese population was reported. In addition, other authors also estimated aflatoxin exposure of Portuguese children (1-3 years) and reported a potential health concern associated to the exposure, wherein AFB1 was the main contributor. Considering the potential risks associated to Portuguese exposure to aflatoxins through diet, and the potential influence of CC on the temperature, humidity, precipitation and consequently on the mycotoxin contamination of food products, this presentation will discuss the CC impact on public health. To face this objective, burden of disease (BoD) associated to aflatoxin exposure of the Portuguese population will be estimated, for the first time, using a model of three components: an exposure, health-outcome and disability adjusted life years (DALY) modules. BoD of different scenarios will be discussed in light of the current knowledge about recent estimates of CC impact in Europe.
- Aflatoxins and ochratoxin A in baby foods and analysis of interactive cyto- and genotoxic effects in a human intestinal cell linePublication . Tavares, Ana; Alvito, Paula; Loureiro, Susana; Louro, Henriqueta; Silva, Maria JoãoMycotoxins are natural fungal metabolites and food contaminants with potential to cause severe acute and chronic conditions. Food contamination with mycotoxins such as aflatoxins (AF) and ochratoxin A (OTA) have been causing great concern, especially due to their potential mutagenic and carcinogenic effects. Children are especially vulnerable to the deleterious effects of these mycotoxins due to their physiological immaturity and high metabolic rate. Previous studies showed the co-occurrence of low concentrations of aflatoxins and OTA in baby foods. However, studies addressing potential interactive cyto- and genotoxic effects between these toxins are still scarce. In the present study we aimed to develop and validate a method for detection and quantification of total aflatoxins (B1, B2, G1, G2), AFM1 and OTA, and to evaluate the cytotoxic and genotoxic effects of mixtures of AFM1 and OTA, comparatively to their individual effects, in a human-derived intestinal cell line. A method based on immunoaffinity column cleanup and High Performance Liquid Chromatography with fluorescence detection (HPLC-FD), was applied and validated for total aflatoxins, AFM1 and OTA. The method was adequate for the analysis of these mycotoxins in baby foods and met the requirements of validation and quality control. The application of the method to a small set of baby foods marketed in Portugal showed an absence of quantifiable amounts of these mycotoxins. The individual and combined cytotoxic and genotoxic effects of AFM1 and OTA were characterized in Caco-2 cells using the Neutral Red and the Comet assays, respectively. A dose-dependent cytotoxicity was observed after individual exposure to OTA and AFM1, and the IC50 values were determined. The cytotoxic effect observed for several AFM1 and OTA mixtures was compared to the expected effect predicted by concentration addition (CA) and independent action (IA) conceptual models, using the MIXTOX model. A preliminary approach regarding the total data pool and considering the CA model as the most conservative model, pointed to an antagonistic cytotoxic effect caused by the mixture of both mycotoxins. However, a dose level deviation was observed after IA modelling, reflecting antagonism at low dose levels and synergism at higher dose levels. To better support data modelling, further cytotoxicity results from mixtures will be obtained and analyzed. To which respects the genotoxic effects, no induction of DNA damage was observed for the tested low doses, neither for individual toxins nor for their mixtures. The present study reinforces the relevance of exploring possible interactive adverse effects of mycotoxins that can contaminate foodstuff and thus having impact in human health. Future studies will face the challenge of understanding the mode of action of such mycotoxins when in mixture, in order to try predicting their effects.
- Alimentos processados: onde estamos e para onde precisamos ir?Publication . Albuquerque, T.G.; Oliveira, M.B.P.P.; Costa, H.S.Introduction: In the last decades, with the industrialization and globalization of food systems, food processing has grown rapidly, contributing to the wide variety of foods, with different health impacts. Furthermore, consumers are increasingly looking for processed foods, which are practical, tasty, attractive, and economic. The inadequate consumption of this type of food is associated with the early development of noncommunicable diseases. It is estimated that inadequate eating habits contribute, in the Portuguese population, to the loss of 15.4% of healthy life years. The Portuguese population has an average salt intake of 10.3 g/day, which is more than the double of WHO recommendations, and it is linked with hypertension, a Public Health concern. Regarding trans fats, since the nineties, the occurrence data for Portuguese foods was not updated. The main objectives of this work were to develop and deepen the scientific knowledge regarding the nutritional quality and safety of processed foods; to deepen knowledge about the formation, occurrence and mitigation of potentially carcinogenic and toxic compounds; and to contribute with fundamental information for the implementation of food and nutrition policies aiming to improve the health and nutritional status of the population. Materials and Methods: Around 300 processed foods were acquired in the main commercial surfaces, fast-food restaurants, pastries and bakery stores of Portugal. The selected foods were evaluated concerning salt, fat and fatty acids composition; influence of cooking methods on overall nutritional quality, accuracy of labelling information and potentially carcinogenic and toxic compounds occurrence. Results: The obtained results allowed to conclude that trans fats content decreased over the years; the contents of salt and saturated fat are still high; more data on the influence of cooking methods on the nutritional quality and safety of processed foods is needed. Nevertheless, it is notable that food industry is making efforts to enhance the overall quality of their products and the information provided to consumers by means of the label. Discussion and Conclusions: The results reported wherein will be used as a starting point to know the current amount of salt, saturated and trans fats in processed foods commercialized in Portugal, as well as to monitor how their reduction in processed foods is being achieved, or to evaluate the current intake of these nutrients by the Portuguese population. Due to the high consumption of processed foods by the different age groups of the population, and their impact on health, it is fundamental to promote strategies that involve the food industry and authorities with responsibilities in Public Health and Human Nutrition, aiming to contribute to safer and nutritionally balanced processed foods.
- An emergent challenge: mycotoxins, climatic change and human healthPublication . Alvito, PaulaDuring the past 60 years, it has become clear that the world has to deal with mycotoxin exposure. Mycotoxins are a group of naturally occurring toxic chemical substances, produced mainly by filamentous fungi that can produce adverse health effects when consumed by humans and animals. It is known that mycotoxins have nephrotoxic, genotoxic, teratogenic, carcinogenic, and cytotoxic properties and, as a consequence, these toxins may cause liver carcinomas, renal dysfunctions, and also immunosuppressed states. Changes in temperature, precipitation, and atmospheric CO2 concentration are expected to carry along an increased risk of mycotoxin contamination mainly associated with cereal crops in the field, and might have an impact on the geographical distribution of certain cereals, mycotoxigenic fungi and their mycotoxins. The large impacts of global warming projected on crops worldwide will subsequently influence food security, by reducing yields and thus food availability, and food and feed safety. Despite prevention methods and strict regulations, mycotoxins are still present in the feed and food chain, and could produce mycotoxicoses. Mycotoxicosis can occur at every stages of life, and it can affect the individuals differently according to their age. The harmful effects of mycotoxins on cell division can lead to drastic consequences, which are even more severe during intrauterine life. Within this context, a recent ongoing project on early-life exposure to mycotoxins and its impact on health, EarlyMYCO (PTDC/MED-TOX/28762/2017), will be presented and discussed, as a contribute to evaluate mycotoxins exposure of pregnant women and child and associated risks, during first 1000 days of life.
- Analytical methods to assess inorganic contaminants in foods. Quality control on food composition, including trace elementsPublication . Coelho, InêsContaminants in food can be of different origins and types. Adequate analytical methods are fundamental to assess contaminants in food. The methodology of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is currently used in numerous research fields, including biomedicine, pharmaceutics, geochemistry, proteomics, materials science, food safety and the nuclear industry. The principal advantages of this methodology are multielement capacity, high sensitivity, hyphenated techniques, wide working range (linearity) and high sample throughput. The reliability of ICP-MS results is ensured by rigorous quality control. Some trace elements analysed by ICP-MS integrate the Portuguese Food Composition Database, a national reference document for the composition of foods consumed in Portugal. This document includes information about 42 nutrients in different foodstuffs.
- Antioxidant activity and characterization of antioxidants from Argentina OcaPublication . Rego, Andreia; André, Catarina; Delgado, Inês; Samman, Norma; Castanheira, IsabelOverview: - Objectives - Introduction • Oca • Phenolic compounds - Methods • Sample • Extraction Method • Antioxidant activity • Total Phenolic Content • UPLC-PDA - Results and Discussion • DPPH • TPC • UPLC-PDA - Conclusions
- Antioxidantes naturales aplicados a envases activos alimentarios: evolución recientePublication . Sanches-Silva, Ana; Costa, Denise; Albuquerque, T.G.; Castilho, Maria Conceição; Ramos, Fernando; Machado, Ana V.; Costa, H.S.Recent Advances in Antioxidant Active Food Packaging: Food oxidation; Antioxidants; Food Packaging; Active Packaging; Legislation; Natural antioxidants.