No abstract

The aim of the present study was to evaluate the effects of gamma irradiation on cytotoxicity and phenolic compounds of Thymus vulgaris L. and Menta  piperita L. (methanolic extracts), used in traditional medicine. Thirteen and fourteen phenolic compounds, including caffeoyl derivatives and flavonoid glycosides, were detected in T. vulgaris and Mentha piperita, respectively, none of which was affected by the irradiation dose used (10 kGy). Furthermore, the irradiation up to 10 kGy did not change the cytotoxic properties of peppermint samples on tumor cell lines (MCF-7, NCI-H460, HeLa and HepG2), whereas thyme samples irradiated at 10 kGy increased their cytotoxicity in the assayed tumor cell lines compared with samples submitted to 2 and 5 kGy. All in all, the dose of 10 kGy was considered as suitable to be applied for the purpose of disinfestation and microbial decontamination of these plants without modifying their phenolic composition and bioactive properties.

The aim of this study was to evaluate the indoor (I) and outdoor (O) levels of NO₂, speciated volatile organic compounds (VOCs) and carbonyls at fourteen primary schools in Lisbon (Portugal) during spring, autumn and winter. Three of these schools were also selected to be monitored for comfort parameters, such as temperature and relative humidity, carbon dioxide (CO₂), carbon monoxide (CO), total VOCs, and both bacterial and fungal colony-forming units per cubic metre. The concentration of CO₂ and bioaerosols greatly exceeded the acceptable maximum values of 1800 mg m⁻³ and 500 CFU m⁻³, respectively, in all seasons. Most of the assessed VOCs and carbonyls occurred at I/O ratios above unity in all seasons, thus showing the importance of indoor sources and building conditions in indoor air quality. However, it has been observed that higher indoor VOC concentrations occurred more often in the colder months, while carbonyl concentrations were higher in the warm months. In general, the I/O NO₂ ratios ranged between 0.35 and 1, never exceeding the unity. Some actions are suggested to improve the indoor air quality in Lisbon primary schools.

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There is an ever-increasing global demand from consumers for high-quality foods with major emphasis placed on quality and safety attributes. One of the main demands that consumers display is for minimally processed, high-nutrition/low-energy natural foods with no or minimal chemical preservatives. The nutritional value of raspberry fruit is widely recognized. In particular, red raspberries are known to demonstrate a strong antioxidant capacity that might prove beneficial to human health by preventing free radical-induced oxidative stress. However, food products that are consumed raw, are increasingly being recognized as important vehicles for transmission of human pathogens. Food irradiation is one of the few technologies that address both food quality and safety by virtue of its ability to control spoilage and foodborne pathogenic microorganisms without significantly affecting sensory or other organoleptic attributes of the food. Food irradiation is well established as a physical, nonthermal treatment (cold pasteurization) that processes foods at or nearly at ambient temperature in the final packaging, reducing the possibility of cross contamination until the food is actually used by the consumer. The aim of this study was to evaluate effects of gamma radiation on raspberries in order to assess consequences of irradiation. Freshly packed raspberries (Rubus idaeus L.) were irradiated in a (60)Co source at several doses (0.5, 1, or 1.5 kGy). Bioburden, total phenolic content, antioxidant activity, physicochemical properties such as texture, color, pH, soluble solids content, and acidity, and sensorial parameters were assessed before and after irradiation and during storage time up to 14 d at 4°C. Characterization of raspberries microbiota showed an average bioburden value of 10(4) colony-forming units (CFU)/g and a diverse microbial population predominantly composed of two morphological types (gram-negative, oxidase-negative rods, 35%, and filamentous fungi, 41%). The inactivation studies on the raspberries mesophilic population indicated a one log reduction of microbial load (95% inactivation efficiency for 1.5 kGy), in the surviving population mainly constituted by filamentous fungi (79-98%). The total phenolic content of raspberries indicated an increase with radiation doses and a decrease with storage time. The same trend was found for raspberries' antioxidant capacity with storage time. Regarding raspberries physicochemical properties, irradiation induced a significant decrease in firmness compared with nonirradiated fruit. However, nonirradiated and irradiated fruit presented similar physicochemical and sensory properties during storage time. Further studies are needed to elucidate the benefits of irradiation as a raspberries treatment process.

Ochratoxin A (OTA) is one of the main mycotoxins that can be found in food. The use of gamma radiation is a technique for preserving food that may exert some effects on mycotoxins. OTA was irradiated in its dry form, in aqueous and in methanolic solutions, and in wheat flour, grape juice and wine. Additionally, the toxicity of OTA irradiated in water was tested. In aqueous solutions, more than 90% of the OTA was degraded by γ-radiation doses ≥2.5kGy, and a 2-fold reduction in OTA cytotoxicity was observed. In food matrices, the elimination of OTA by γ-radiation was found more difficult, as radiation doses of 30kGy eliminate at most 24% of the OTA. Higher moisture content of food matrices did not substantially increase OTA elimination. It is concluded that OTA is very sensitive to irradiation in water solutions but resistant in its dry form and in food matrices.

No abstract

Mushroom production and consumption is increasing, but high perishability still represents a major commercial drawback. Besides increasing the product shelf-life, conservation processes should be innocuous to consumers. Therefore, the effects of gamma and electron beam radiation on chemical and nutritional composition of fresh samples of Agaricus bisporus Portobello (a highly commercialized species) were assessed. Mushrooms were irradiated at 1, 2 or 5 kGy, and analyzed at different times (0, 4 and 8 days). In general, irradiation type had higher effect than irradiation dose. Gamma irradiation was associated with higher contents in sugars and ergosterol, while the 5 kGy dose, independently of irradiation source, was linked with higher protein levels. Nonetheless, irradiation might represent an effective preservation methodology for Portobello mushrooms, as it was effective in maintaining their chemical profiles (except for minor organic acids and saturated fatty acids) throughout the assayed time intervals.