Browsing by Author "Rafalski, Andrzej"
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- Application of gamma and electron beam irradiation for chestnuts conservationPublication . Carocho, Márcio; Antonio, Amilcar L.; Barreira, João C.M.; Barros, Lillian; Rafalski, Andrzej; Botelho, M. Luísa; Oliveira, Beatriz; Bento, Albino; Ferreira, Isabel C.F.R.Due to the distribution of low quality products, adulteration, counterfeit on the Ukrainian market, the widening of export-import supplies, it is too important to develop criteria and methods for the identification domestic and exported food products, detection of adulteration, techniques and methods assessing quality and early spoilage screening of food products using modern express methods of analysis. Such method is an electronic nose system based on chemical sensors, for example, piezoelectric quartz microweighing, combined with complex computer algorithms registration, processing and decision making («artificial intelligence»). Odor is one of the most significant parameters among the sensory properties of foods. The representative flavor of volatile compounds, so-called fingerprint, may provide knowledge about safety and particular characteristic of food, acting sometimes as an indicator of process mistake as well. Off-flavors may include substances originating from the metabolism of spoilage microorganisms, bacteria and fungi; which may naturally or accidentally contaminate the products during their production. Electronic noses (EN) are instruments based on an array of semi low selective sensors that are selected on the chemical affinity to individual components of the analyzed gas mix and vapors and pattern recognition methods. ENs have been applied in various food contexts such as process monitoring, freshness evaluation, shelf-life investigation, authenticity determination, and product traceability. The object of our research is express methods development of identification, estimation of quality and early spoilage screening of dairy and meat products using multisensory electronic nose system based on piezosensors. The absolute advantages of electronic sensory analyzers are their versatility, portability, ability to automate measurements and interpretation of signals, reproducibility of results.
- 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.
- Effects of gamma and electron-beam irradiation on the antioxidant potential of Melissa officinalis L. infusionsPublication . Pereira, Eliana; Barros, Lillian; Antonio, Amilcar L.; Rafalski, Andrzej; Ferreira, Isabel C.F.R.Gamma and electron beam irradiation are two processes authorized for food processing, characterized as technically and economically feasible procedures, and safe, with a powerful antimicrobial effect. These decontamination methods have advantages that are increasingly attracting the market and present a good alternative to other methods [1,2]. In this work, the effects of gamma irradiation and electron beam on antioxidant activity of Melissa officinalis L., were evaluated. Infusions were prepared from non-irradiated and irradiated samples (1 and 10 kGy), and their radical scavenging activity, reducing power and inhibition of lipid peroxidation were assessed. According to the results obtained, it was concluded that in samples exposed to gamma irradiation, the highest antioxidant potential was displayed by the infusions prepared from the samples irradiated at 1 kGy, as well as the highest concentration of phenols and flavonoids. Regarding the samples exposed to electron beam irradiation, the mentioned effects were not so evident and, in most of the cases, no changes were observed among non-irradiated and irradiated samples. Overall, irradiation might represent a suitable solution for M. officinalis postharvest treatment, since the use of irradiation did not interfere with its antioxidant properties, and gamma irradiation at 1 kGy even improved some of the antioxidant potential, preserving the bioactive compounds that confer health beneficial effects.
- Electron-beam irradiation as an alternative to preserve nutritional, chemical and antioxidant properties of dried plants during extended storage periodsPublication . Pereira, Eliana; Antonio, Amilcar L.; Rafalski, Andrzej; Barreira, João C.M.; Barros, Lillian; Oliveira, Beatriz; Ferreira, Isabel C.F.R.According to current market demands, there is an increasing need for improved conservation methodologies. In addition to an extension in shelf-life, food products should preserve their compositional integrity and bioactive properties throughout storage time. Irradiation technology has been progressively considered as a feasible conservation technology. Electron-beam irradiation, in particular, might be predominantly suitable to be applied in food products with reduced thickness, such as aromatic and medicinal plants. In this study, the effects of e-beam irradiation on chemical, nutritional and antioxidants parameters of different plant species were evaluated. To assess the potential of this technology over extended periods, plant samples were stored for the first time up to a maximum of 18 months. Despite some heterogeneity among the effects produced in each plant species, electron-beam treatment attenuated the reduction of individual compounds (primarily, free sugars, organic acids, tocopherols and polyunsaturated fatty acids) verified in non-irradiated samples, showing its potential as an alternative conservation technology.
- Extending the use of irradiation to preserve chemical and bioactive properties of medicinal and aromatic plants: a case study with four species submitted to electron beamPublication . Pereira, Eliana; Antonio, Amilcar L.; Rafalski, Andrzej; Barreira, João C.M.; Barros, Lillian; Ferreira, Isabel C.F.R.The effects of gamma irradiation on Aloysia citrodora, Melissa officinalis, Melittis melissophyllum and Mentha piperita were previously evaluated. Herein, the same species were treated with electron-beam irradiation (EB) and the same parameters were evaluated. Instead of presenting absolute values for each studied parameter, data were evaluated as percentage of induced variation. Besides the newly obtained results, data from a previous work was recalled and normalized in the same manner. Several examples of percentage variations specific to a plant species or irradiation condition were found. Nevertheless, it was not possible to identify unequivocal trends. Even so, when evaluated in an integrative way, the parameters with highest discriminating ability among irradiation conditions or plant species were fatty acids and bioactive indicators. Comparing the effects of gamma and EB irradiations, it might be concluded that the most suitable solution to irradiate aromatic plants would be EB, independently of the used dose.
- Gamma and electron beam irradiation as an alternative for postharvest treatment: a case study with chestnutsPublication . Carocho, Márcio; Antonio, Amilcar L.; Barreira, João C.M.; Barros, Lillian; Rafalski, Andrzej; Bento, Albino; Ferreira, Isabel C.F.R.Chestnut fruits are an important food commodity in the Northeast region of "Trás-osMontes", representing an income of approximately 17 M€ and being Porn1gal one of the: world's biggest producer. Due to environmental concerns a broad spectrum fumigant, methyl bromide, was banned in 20 I 0 by the European Union. Since then, no adequate postharvest treatment has been implemented, fostering research on suitable alteratives. Our research group has been testing gamma and electron beam irradiation as an alternative postharvest treatment for chestnuts. On a first attempt to evaluate the influence of irradiation, various doses were tested (0, 0.5, I, 3 and 6 kGy) along different storage times (0, 30 and 60 days). The effects were assessed in the most important chemical parameters, namely nutritional, antioxidant, sugar, fatty acid, tocopherol, organic acid and triacylglyccrol profiles, in which, all seemed to be altered to a greater extent by storage time than by the different doses. Another important conclusion was the validation of I kGy as the optimal dose for chestnuts conservation. This conclusion sustained the venture to extend the study to four varieties (Longal, Judia, Cotaand Palummina) with a fixed dose of I kGy for both gamma radiation and electron beam. The results were processed through principal component analysis and confined that both gamma (1) and electron beam (2) irradiation showed high potential to be used as postharvest conservation technology. The most marked differences were found between the four different cultivars, especially Cola and Palummina, while non-irradiated and irradiated chestnuts proved to have very similar profiles in all the assayed parameters, with irradiation having an attenuating effect.
- Gamma and electron-beam irradiation as viable technologies for wild mushrooms conservation: effects on macro- and micro-elementsPublication . Fernandes, Ângela; Barreira, João C.M.; Antonio, Amilcar L.; Rafalski, Andrzej; Morales, Patricia; Férnandez-Ruiz, Virginia; Oliveira, Beatriz; Martins, Anabela; Ferreira, Isabel C.F.R.The consumption of mushrooms is increasing all over the world as a result of their sensorial and nutritional qualities. Among their nutrients, mushrooms present high levels of macro- and micro-elements. The qualitative composition in these elements is, however, often unknown. Mushrooms are known also as being very perishable products. Gamma rays or electron-beam irradiation has been applied to improve their shelf life and decrease health hazards caused by microorganisms. In addition, the effects of irradiation on the physicochemical and nutritional parameters of wild mushrooms have been studied by our research group. Nevertheless, the effects on essential macro- and micro-elements of these natural matrices are still unknown. The effects of gamma and electron-beam irradiation on the macro- and micro-elements profiles were evaluated in Boletus edulis, Hydnum repandum and Macrolepiota procera. The same elements were detected in the three species with some quantitative differences. The profiles obtained allowed the definition of proper dietary intakes, thus preventing undesirable effects derived from consuming mushrooms in quantities that exceed threshold levels of these minerals. The applied irradiation doses did not show a systematic effect on the macro- and micro-elements profiles, except for the 10 kGy. Accordingly, irradiation treatment, using gamma rays or electron beam up to 6 kGy, is a suitable technique to disinfest and/or decontaminate wild mushrooms, independently of their species or physical state.
- How does electron beam irradiation dose affect the chemical and antioxidant profiles of wild dried Amanita mushrooms?Publication . Fernandes, Ângela; Barreira, João C.M.; Antonio, Amilcar L.; Rafalski, Andrzej; Oliveira, Beatriz; Martins, Anabela; Ferreira, Isabel C.F.R.As all the mushrooms, Amanita species experiment several conservation problems, with a post-harvest life limited to a few days. Drying is one of the most used methods in mushrooms preservation. Food irradiation is another possible way to improve food quality and insure its security. Among the emerging irradiation technologies, electron beam has wide application, allowing high throughput, wide flexibility and potential, without any negative effect on the environment. The effects of different electron beam irradiation doses in Amanita genus, were assessed by measuring the changes produced on a wide variety of nutritional, chemical and antioxidant indicators. The evaluated profiles indicated differences among non-irradiated and irradiated samples, but a high similarity among different doses. This finding advises the highest assayed dose (10 kGy), ensuring higher effectiveness from the decontamination and disinfestation point of view, without having stronger effects than those observed for the lower doses.
- Influence of e-beam postharvest irradiation in the colour of four European chestnut fruit varieties of Castanea sativa Mill.Publication . Antonio, Amilcar L.; Carocho, Márcio; Bento, Albino; Rafalski, Andrzej; Quintana, BegoñaIn this study we characterized the physical dimensions of four European chestnut varieties of Castanea sativa, 3 from Portugal (Cota, Longal and Judia) and 1 from Italy (Palummina). The typical physical dimensions of the different chestnut fruit varieties could be used to optimize the process in an irradiation preservation treatment. The chestnut fruits were submitted to an irradiation preservation treatmen with electron beam, at 1 kGy, and the colour parameters (CIE L*, a*, b*) of the skins, fruit and interior (half-cutted), were monitored after irradiation treatment and along 2 months of storage. We could conclude that e-beam irradiation, for the dose of 1 kilogray, did not induce any significant change in the skin, fruit and interior’s colour parameters.
- Influence of electron beam irradiation in the organic acids profile of Portuguese chestnuts (Castanea sativa Mill.)Publication . Carocho, Márcio; Antonio, Amilcar L.; Barros, Lillian; Barreira, João C.M.; Bento, Albino; Rafalski, Andrzej; Ferreira, Isabel C.F.R.Organic acids are primary metabolites that play important roles in plant metabolism and confer distinct flavors in fruits. Their consumption is beneficial for humans, namely against certain illnesses. The food industry uses them as preservatives and flavor enhancers. In fruits conservation and transport, organic acids should be preserved at all costs in order to maintain physical quality and pleasant flavors until they reach the consumer. In 2010, due to European legislation, methyl bromide was banned as a conservation method for chestnuts due to its toxicity to operators and negative effects to the environment. Since then, various innovative techniques have been pursued, and irradiation has proved to be a viable, cheap and environment friendly one. Our research group has studied that both gamma and electron beam irradiation as a conservation method in Portuguese chestnuts and proven that they do not alter in a significant way the nutritional value and antioxidant potential of these fruits. Herein, the influence of increasing doses of electron beam irradiation (0- control, 0.5, 1, 3 and 6 kGy) and different storage times (0, 30 and 60 days), in the organic acids profile of Portuguese chestnuts, was studied. Ultra-fast liquid chromatography coupled to a photodiode array detector (UFLC-PDA) was used to quantify oxalic, quinic, malic, ascorbic, citric, fumaric, succinic and shikimic acids. Our results indicate that the irradiation doses did not significantly influence the quantity of organic acids in the samples, proving to be a safe and valuable conservation technique.