Impact of galactic cosmic ray simulation on nutritional content of foods.

Foods packaged for future deep-space exploration missions may be prepositioned ahead of astronaut arrival and will be exposed to galactic cosmic rays (GCRs) and solar radiation in deep space at higher levels and different spectrums than those found in low-Earth orbit (LEO). In this study, we have evaluated the impact of a GCR simulation (approximately 0.5 and 5 Gy doses) at the NASA Space Radiation Laboratory (NSRL) on two retort thermostabilized food products that are good sources of radiation labile nutrients (thiamin, vitamin E, or unsaturated fats). No trends or nutritional differences were found between the radiation-treated samples and the control immediately after treatment or one-year after treatment. Small changes in a few nutrients were measured following one-year of storage. Further studies may be needed to confirm these results, as the foods in this study were heterogeneous, and this may have masked meaningful changes due to pouch-to-pouch variations.

Synergistic bactericidal effects of pairs of photosensitizer molecules activated by ultraviolet A light against bacteria in plasma.

BACKGROUND: The current approach to reducing bacterial contamination in blood transfusion products is through detection or pathogen reduction methods, some of which utilize ultraviolet (UV) light photosensitizers. A small number of photosensitizers are being used as single agents in combination with UV light, but their efficacy can be limited against some pathogens. Benzophenone (BP) and vitamins B1, B6, and K3 have been identified as effective UVA photosensitizers for inactivation of bacteria. We evaluated whether combining pairs of photosensitizers in this group would have synergistic bactericidal effects on Gram-negative and Gram-positive bacteria. STUDY DESIGN AND METHODS: Bacteria species of Escherichia coli, Bacillus cereus, Staphylococcus aureus, and Klebsiella pneumoniae were mixed with 0 to 100 mM concentrations of photosensitizers and exposed to UVA irradiation at 18 J/cm2 to assess their bactericidal effects. RESULTS: Single photosensitizers irradiated with UVA produced a range of bactericidal activity. When combined in pairs, all demonstrated some synergistic bactericidal effects with up to 4-log reduction above the sum of activities of individual molecules in the pair against bacteria in plasma. Photosensitizer pairs with BP had the highest synergism across all bacteria. With vitamin K3 in the pair, synergism was evident for Gram-positive but not for Gram-negative bacteria. Vitamin B1 and vitamin B6 had the least synergism. These results indicate that a combination approach with multiple photosensitizers may extend effectiveness of pathogen reduction in plasma. CONCLUSIONS: Combining photosensitizers in pathogen reduction methods could improve bactericidal efficacy and lead to use of lower concentrations of photosensitizers to reduce toxicities and unwanted side effects.

A new method for determining the absorbed dose in a radiation field by using a thiamine hydrochloride aqueous solution.

This research investigated the ionizing radiation effect on thiamine hydrochloride (TH) and its usability as an irradiation dosimeter. The fundamental principle is to determine the concentration variations of TH solutions with high-performance liquid chromatography (HPLC) after exposing to γ-rays. The decreasing peak area of TH in the HPLC chromatogram forms a linear relationship with the rising radiation dose. We investigated the characteristics and suitable application range of the TH as a new radiation dosimeter. The influence factors and mechanism of the reaction induced by radiation were also discussed. According to the correlation between the concentration and the radiation dose, 0.3 g/L of a TH solution is suitable for the 0.1-10 kGy dose range, and 2 g/L is appropriate for 0.1-20 kGy. The easy availability and the simple, but stable, chemical structure of thiamine makes it a potential candidate for radiation dose research. Also, the preparation proceeding for sampling is easy, and the result can be automatic monitored by liquid chromatography.

Avaliaçäo dos efeitos da radiaçäo ionizante de 'POT. 60 Co' em propriedades físicas, químicas e nutricionais dos feijöes Phaseolus vulgaris L. e Vigna unguiculata (L.) Walp / Evaluation of he effects of 'POT. 60 Co' in nutritional, chemical and physicas properties of beans Phaseolus vulgaris L and Vigna unguiculata (L.) Walp

Foram estudados os efeitos da radiaçäo ionizante de 'POT. 60 Co' nas doses de 0; 0,5; 1,0; 2,5; 5,0 e 10 kGy e do período de estocagem de 6 meses nos feijöes, Phaseolus vulgaris L., variedade carioca e Vigna unguiculata (L.) Walp, variedade macaçar. Determinou-se o tempo de cocçäo, seguido das análises: sensorial, vitaminas B1, B2 e B6, quantidade protéica, avaliaçäo biológica em ratos [Consumo Alimentar (CA) e Ganho de Peso (GP) em gramas, Digestibilidade aparente (NPUa) e Valor Biológico aparente (VBa)] e a aplicabilidade de métodos de detecçäo de alimentos irradiados com testes de germinaçäo, análise da migraçäo do DNA, termoluminescência e análise dos hidrocarbonetos formados pela radiaçäo. Mudanças no tempo de cocçäo foram observadas em todas as doses. Quando aplicadas doses até 1 kGy, näo houve modificaçäo das qualidades nutricionais dos feijöes processados por radiaçäo. A aplicaçäo dos métodos de detecçäo de alimentos irradiados propostos, possibilitaram a detecçäo dos feijöes irradiados com doses baixas de até 0,5 kGy

The effect of microwave heating on vitamins B1 and E, and linoleic and linolenic acids, and immunoglobulins in human milk.

Breast milk was treated with (1) conventional heating (in water bath) vs microwave heating; (2) microwave heating at two power levels (30% and 100%); (3) increasing final temperatures; and (4) microwave thawing vs refrigerator thawing and examined for changes in specific immunoglobulins to a pool of E. coli and poliovirus type 1 antigens, vitamins E and B1, and the polyunsaturated fatty acids linoleic and linolenic acid. Immunoglobulin activities were stable until final milk temperatures of around 60-65 degrees C were reached, and total inactivation occurred at 77 degrees C. Heating even to high final temperatures did not change contents of vitamins and polyunsaturated fatty acids. No differences in immunoglobulins and nutrients were demonstrated between microwave heating and conventional heating, and between power levels or thawing methods. The study shows that microwave heating of human milk can be performed without significant losses of examined immunoglobulins and nutrients, provided that final temperatures are below 60 degrees C.

[Reduction of radiation-induced vitamin E- and B1- losses by irradiation of foodstuffs at low temperature and by exclusion of atmospheric oxygen]. / Verminderung von strahleninduzierten Vitamin-E- und -B1-Verlusten durch Bestrahlung von Lebensmitteln bei tiefen Temperaturen und durch Ausschluss von Luftsauerstaff.

The protective effect of low temperatures during irradiation on vitamin B1 and E levels in foods is not abolished by subsequent storage or heating. Egg powder irradiated at 1 Mrad in the presence of air and stored for 4 months at ambient temperature lost 68% of its thiamin content when irradiated at 20 degrees C, 33% when irradiated at -30 degrees C. Sunflower oil irradiated at 3 Mrad in the presence of air and subsequently heated for 1 hour at 180 degrees C lost 98% of its alpha-tocopherol content when irradiated at 20 degrees C, 65% when irradiated at -30 degrees C. Exclusion of atmospheric oxygen by packaging under nitrogen reduced the loss of alpha-tocopherol in irradiated (0.1 Mrad) rolled oats after 8 months of storage from 56 to 5% and the loss of thiamin from 86 to 26%. Vacuum packaging was equally effective during the first 3 months and somewhat less effective during the following 5 months. Packaging under carbon dioxide showed no advantage over packaging in air. Sensory evaluation of rolled oats, raw or cooked, 1 and 3 months after irradiation with 0.1 Mrad indicated no significant quality difference between unirradiated and irradiated samples packaged under nitrogen.

[Thiamine in irradiated foodstuffs I. Influence of different radiation conditions and of time after irradiation]. / Thiamin in bestrahlten Lebensmitteln I. Einfluss verschiedener Bestrahlungsbedingungen und des Zeitablaufs nach der Bestrahlung

Effects of 10 MeV-electron radiation on thiamine dichloride in crystalline form and in solution, and on thiamine in dried whole egg are described. Both in the dry state and in aqueous solutions, radiation induced reactions continue to affect thiamine over a considerable period of time after irradiation. Thiamine losses decrease in the order: dry thiamine dichloride, aqueous solution, hydrochloric acid solution, dried whole egg.