Application of Ionizing Radiation for a Sustainable Environment

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Gamma radiation-induced effects on the recovery of pharmacologically active polyphenols from tuberaria lignosa medicinal plant

Publication . Pinela, José; Prieto Lage, Miguel A.; Barros, Lillian; Antonio, Amilcar L.; Cabo Verde, Sandra; Carvalho, Ana Maria; Oliveira, Beatriz; Ferreira, Isabel C.F.R.

Ionizing radiation has been used for many years as a safer and environmentally friendly alternative comparatively to chemical fumigants to decontaminate medicinal plants and other food commodities [1]. Perennial spotted rockrose (Tuberaria lignosa (Sweet) Samp.) is a highly quoted medicinal plant in the northeast region of Portugal rich in ellagitannin derivatives [2,3]. As polyphenols, these compounds play an important role in human nutrition and display several biological effects, including antioxidant, anti-inflammatory, antitumor, antibacterial, and anti-HIV replication activities [2-4]. However, little is known about the impact of ionizing radiation on the integrity and extractability of these high added-value compounds. This work aimed to investigate the effects of γ-rays irradiation on the extraction and/or degradation kinetics of ellagitannins from T. lignosa aerial parts. The plant material was submitted to irradiation doses up to 10 kGy in a cobalt-60 experimental chamber. Then, the non-irradiated and irradiated plant material was submitted to different solid-liquid extractions, according to a three-level full factorial design, using boiling water as extraction solvent. The ellagitannins were analyzed in a high-performance liquid chromatography (HPLC) system connected to a diode array detector (DAD) and a mass spectrometer (MS). Punicalin, punicalagin isomers, and punicalagin gallate isomers were the most abundant compounds. In general, the extractability of this group of phytochemicals was improved by the irradiation treatment (5 kGy) and longer extraction times (10 min). In addition, the 10 kGy dose did not induced adverse effects. In conclusion, this study demonstrated the suitability of γ-rays irradiation for preserving or improving the extractability of pharmacologically active compounds from T. lignosa aerial parts.

2017Conference object

Open access

Para lá do azul: radiações ionizantes para preservar alimentos

Publication . Antonio, Amilcar L.; Cabo Verde, Sandra; Ferreira, Isabel C.F.R.

A radiação visível representa apenas uma parte do espectro de radiação electromagnética com o qual temos interacção permanente. As radiações com maior energia, para além do azul, como os UV, raios-X ou radiação gama têm diferentes usos tecnológicos. Estas radiações são consideradas ionizantes podendo ser utilizadas na preservação de alimentos, permitindo a inibição da germinação, a eliminação de insectos ou microrganismos patogénicos. O conhecimento destas aplicações tem mais de um século e o seu uso industrial meio século. Propomo-nos apresentar o estado-de-arte relativo ao uso desta tecnologia em Portugal em alimentos, apresentando estudos recentes e perspectivas futuras.

2016Conference object

Open access

Modified atmosphere packaging and post-packaging irradiation of Rumex induratus leaves: a comparative study of postharvest quality changes

Publication . Pinela, José; Barreira, João C.M.; Barros, Lillian; Cabo Verde, Sandra; Antonio, Amilcar L.; Oliveira, Beatriz; Carvalho, Ana Maria; Ferreira, Isabel C.F.R.

The effects of conventional and inert-gas enriched atmospheres, as well as those caused by different γ-irradiation doses, on buckler sorrel (Rumex induratus) leaves quality were evaluated and compared after 12 days of storage at 4 °C. The green colour of the abaxial surface of the leaves was relatively stable, as well as the carbohydrates content and the calorific value. The storage time decreased the amounts of fructose, glucose, trehalose, α-tocopherol, and β-tocopherol and increased the levels of total organic acids and δ-tocopherol. The total tocopherols content was higher in air-packaged non-irradiated leaves, antioxidant compounds that may have contributed to the preservation of polyunsaturated fatty acids (PUFA). Some antioxidant properties were also favoured during storage. It was found that the overall postharvest quality of buckler sorrel leaves is better maintained with the argon-enriched atmospheres, while the 6 kGy dose was a suitable option to preserve PUF+A during cold storage. This study highlights the suitability of the applied postharvest treatments and the interest to include buckler sorrel leaves in contemporary diets.

2016Journal article

Restricted access

Postharvest quality of fresh-cut watercress: impact of non-thermal treatments based on inert-gas and ionizing radiation

Publication . Pinela, José; Barreira, João C.M.; Barros, Lillian; Antonio, Amilcar L.; Cabo Verde, Sandra; Carvalho, Ana Maria; Oliveira, Beatriz; Ferreira, Isabel C.F.R.

Ready-to-eat vegetables are having a growing consumer acceptance for attending to contemporary requirements of convenience, safety and wholesomeness. The growth of this sector has led to the introduction of new food products and the implementation of more efficient and sustainable postharvest technologies1 In this sense, the suitability of modified atmosphere packaging (MAP) and post-packaging gamma irradiation for preserving quality parameters of fresh-cut watercress (Nasturtium officinale R. Br.) during cold storage was evaluated. Wild samples of watercress were rinsed in tap water and a portion was immediately analysed (fresh control). The remaining fresh material was packaged under nitrogen- and argon-enriched atmospheres, air (passive MAP) and vacuum. Air-packaged samples were then irradiated at doses up to 5 kGy in a cobalt-60 chamber. All packaged samples were stored at 4 oc for 7 days. The quality analyses included color, total soluble solids, pH, macronutrients, the individual profiles of sugars, organic acids, tocopherols and fatty acids, and total phenolics and flavonoids. Four in vitro assays based on different reaction mechanisms were also performed to evaluate the antioxidant capacity. After assessing the effect on the individual quality parameters, it was possible to conclude that argon-enriched atmospheres and the 2 kGy dose were suitable choices for preserving quality attributes of watercress during cold storage2 . However, samples irradiated at 5 kGy revealed chemical profiles more prone to exert positive health effects. Thereby, advantageous effects induced by modified atmospheres and ionizing radiation in the quality of fresh-cut watercress were highlighted, justifying the inclusion of this vegetable in human diets.

2015Conference object

Open access

Effects of gamma irradiation in the antimicrobial activity of wild mushroom extracts

Publication . Fernandes, Ângela; Alves, Maria José; Barreira, João C.M.; Antonio, Amilcar L.; Oliveira, Beatriz; Martins, Anabela; Ferreira, Isabel C.F.R.

The interest of mushrooms hás been increasing over time due to their potential in prevention or treatment of different diseases. Mushrooms have been reported for their anticancer, antiinflammatory, and immunosuppressive and antimicrobial properties. In particular, several authors reported the antibacterial activity of extracts prepared from different mushroom species [1]. In spite of these undeniable qualities, mushrooms are one of the most perishable products and tend to loose quality immediately after harvest. Irradiation is recognized as a safe and effective presen/ation method, being used worldwide to increase the shelf life of foods (e. g, fruits and vegetables, spices, grains, meat or seafood, aromatic and medicinal plants and spices) [2, 3]. In the present study, the antibacterial properties of methanolic extracts prepared from Boletus edulis Buli. and Hydnum repandum L. Fr., previously submitted to gamma irradiation, were assessed against clinicai isolates with different resistance profiles (two Gram negative bacteria; Escherichia coli and Proteus mirabilis, isolated from urine, and two Gram positive bactéria: MSSA- methicillin-sensitive Staphylococcus aureus, isolated from wound exudate and MRSA- methidllin-resistant Staphylococcus aureus, isolated from expectoration) from hospitalized patients in Local Health Unit of Mirandela, Northeast of Portugal. The fruiting bodies were collected in Trás-os-Mõntes (Northeast of Portugal) in November 2012. Gamma irradiation was performed in experimental equipment with four Co-60 sources at 1 and 2 kGy doses. The 1 kGy dose does not seem to be the preferable choice to treat B. edufe and H. repandum(which have a better response to the 2 kGy dose). Among the tested extracts, those obtained from B. ecfufe presented the highest activity against ali the tested bacterial. The antimicrobial activity of the mushroom extracts did not suffer significant changes that might compromise applying irradiation as a possible mushroom conservation technology. As a general conclusion, the 2 kGy should be considered as the best choice in terms of antimicrobial activity maintenance.

2015Conference object

Open access