Observations on the water distribution and extractable sugar content in carrot slices after pulsed electric field treatment

peer-reviewedThe impact of pulsed electric field (PEF) processing conditions on the distribution of water in carrot tissue and extractability of soluble sugars from carrot slices was studied. Time domain NMR relaxometry was used to investigate the water proton mobility in PEF-treated carrot samples. Three distinct transverse relaxation peaks were observed in untreated carrots. After PEF treatment only two slightly-overlapping peaks were found; these were attributed to water present in the cytoplasm and vacuole of carrot xylem and phloem tissues. This post-treatment observation indicated an increase in water permeability of tissues and/or a loss of integrity in the tonoplast. In general, the stronger the electric field applied, the lower the area representing transverse relaxation (T2) values irrespective of treatment duration. Moreover an increase in sucrose, β- and α-glucose and fructose concentrations of carrot slice extracts after PEF treatment suggested increases in both cell wall and vacuole permeability as a result of exposure to pulsed electric fields.The authors acknowledge financial support from the Irish Phytochemical Food Network (IPFN) project funded under the Food Institutional Research Measure (FIRM, 06/TNI/AFRC6) of the Irish Department of Agriculture, Food and Marine. Dr. Aguiló-Aguayo thanks Generalitat of Catalonia for the postdoctoral grant Beatriu de Pinós (BP-DGR2010). E. Balagueró thanks the Lifelong Learning Programme for the internship grant Leonardo da Vinci MOTIVA3 (201 1-1-ES1-LEO02-34225)

Hypoxia-induced treatment failure in advanced squamous cell carcinoma of the uterine cervix is primarily due to hypoxia-induced radiation resistance rather than hypoxia-induced metastasis

Poor outcome of treatment in advanced cervix carcinoma has been shown to be associated with poor oxygenation of the primary tumour. Hypoxia may cause radiation resistance and promote lymph-node metastasis. The purpose of the study reported here was to investigate whether hypoxia-induced treatment failure in advanced cervix carcinoma is primarily a result of hypoxia-induced radiation resistance or the presence of hypoxia-induced lymph-node metastases at the start of treatment. Thirty-two patients with squamous cell carcinoma of the uterine cervix were included in the study. Radiation therapy was given with curative intent as combined external irradiation and endocavitary brachytherapy. The oxygenation status of the primary tumour was measured prior to treatment using the Eppendorf p O 2 Histograph. Pelvic and para-aortal lymph-node metastases were detected by magnetic resonance imaging at the time of initial diagnosis. The primary tumours of the patients with metastases (n = 18) were significantly more poorly oxygenated than those of the patients without metastases (n = 14). Multivariate Cox regression analyses involving biological and clinical parameters identified the tumour subvolume having p O 2 values below 5mmHg (HSV (p O 2< 5mmHg) as the only significant, independent prognostic factor for locoregional control, disease-free survival and overall survival. The probabillities of locoregional control, disease-free survival and overall survival were significantly lower for the patients with HSV (p O 2< 5 mmHg) above the median value than for those with HSV (p O 2< 5 mmHg) below the median value. On the other hand, the outcome of treatment was not significantly different for the patients with metastases and the patients without metastases at the start of treatment, irrespective of clinical end-point. Consequently, treatment failure was primarily a result of hypoxia-induced radiation resistance rather than hypoxia-induced lymph-node metastasis, suggesting that novel treatment strategies aiming at improving tumour oxygenation or enhancing the radiation sensitivity of hypoxic tumour cells may prove beneficial in attempts to improve the radiation therapy of advanced cervix carcinoma. © 2000 Cancer Research Campaig

Adding Value to Ready-to-Crustacean Products: Process optimization for "entire" crustaceans using novel technologies

El objetivo general de esta Tesis Doctoral fue optimizar y evaluar el potencial de diferentes tecnologías de procesado en la producción de buey de mar (Cancer pagurus) irlandés listo para el consumo. El primer capítulo de introducción general proporciona una visión global de las diferentes estrategias para la conservación de alimentos y de las tecnologías de procesado disponibles actualmente. Además, se lleva a cabo una revisión de la optimización del procesado de alimentos haciendo énfasis en los tratamientos térmicos. Finalmente, este capítulo resume una visión general del buey de mar, su importancia en la Industria Irlandesa y las prácticas actuales para su procesado. Tras el capítulo de introducción, en primer lugar, se caracterizó la principal flora bacteriana responsable de la alteración del buey de mar listo para consumo y su resistencia frente a los tratamientos térmicos. De los resultados obtenidos, se deduce la importancia de Bacillus spp. y Staphyloccocus spp. como los principales microorganismos presentes en el buey de mar listo para el consumo. El estudio de caracterización termobacteriológica demostró que el tratamiento para inactivar Listeria monocytogenes (F70°C7.5°C = 2 minutos), en este tipo de productos, es efectivo para inactivar todas las células vegetativas presentes de manera natural en el buey de mar. Sin embargo, el mismo estudio también reveló que el tratamiento más severo recomendado para inactivar Clostridium botulinum no proteolítico tipo E, en cangrejo, (F90°C8.6°C = 57 minutos) no resultaba suficiente para alcanzar un nivel similar de inactivación (6 ciclos logarítmicos) de la bacteria esporulada más termorresistente aislada del buey de mar, Bacillus weihenstephanensis. Tras la caracterización de la microbiota del buey de mar, se evaluó el potencial de incorporar la tecnología de ultrasonidos para mejorar el cocinado del buey de mar. Los resultados mostraron que la incorporación de ultrasonidos al cocinado del buey de mar mejoraba los fenómenos de transferencia de calor, lo cual permitió reducir el tiempo total del proceso hasta un 15%. Además, los ultrasonidos también probaron ser efectivos para mejorar los procesos de transferencia de masa producidos durante el cocinado mejorando así la limpieza de los cangrejos en el cocinado. Esto permitiría evitar la etapa de limpieza de los cangrejos antes del envasado que se realiza actualmente en el proceso industrial. Dado el potencial de los ultrasonidos para mejorar los procesos de transferencia de masa durante el cocinado del cangrejo, se evaluó su uso para reducir la concentración de cadmio del buey de mar. Los resultados obtenidos probaron que la combinación de los ultrasonidos con temperaturas moderadas de tratamiento es capaz de reducir el contenido total de cadmio del buey de mar hasta un 22.8%, abriendo la posibilidad de utilizar esta tecnología para afrontar este importante reto en la producción de estos productos.Tras la caracterización de las primeras etapas de la producción de buey de mar (cocción y lavado), se realizó un estudio de optimización del segundo tratamiento térmico, la pasteurización, basado en la cinética de cambio de calidad del producto. De los resultados obtenidos, se deduce que el color de la carne blanca es el parámetro de calidad que se ve más afectado debido al tratamiento térmico, por lo que se caracterizó su cinética de cambio de color, utilizándose como indicador para la optimización del proceso. En base a las ecuaciones desarrolladas en este estudio, el tratamiento térmico requerido para inactivar B. weihenstephanensis sería demasiado severo para retener una buena calidad en el producto final pasteurizado. Por este motivo, se evaluó el uso de tecnologías alternativas (Mano-Sonicacion, Mano-Termo-Sonicacion y radiaciones ionizantes aplicando electrones acelerados) para la inactivación de los esporos aislados del buey de mar. La combinación de ultrasonidos con presión y temperatura mostró un efecto sinérgico para la inactivación de las bacterias esporuladas, lo cual permitiría reducir hasta un 80% el tiempo total de procesado manteniendo unos niveles de inactivación adecuados. La irradiación también probó ser una tecnología efectiva para inactivar las bacterias esporuladas a dosis de tratamiento por debajo del límite establecido por la WHO de 10kGy. Además, la irradiación fue la tecnología para la inactivación de bacterias esporuladas menos afectada por cambios en la especie microbiana contaminante o en las condiciones del medio de tratamiento, lo cual reduciría el riesgo sanitario de los productos pasteurizados si se produjese un error al definir el microorganismo diana o en la composición del producto. Los resultados de esta Tesis Doctoral muestran por tanto el potencial del uso de tecnologías de procesado alternativas a los procesos tradicionales, principalmente el calor, para mejorar la producción de buey de mar irlandés listo para su consumo y afrontar sus retos presentes y futuros. The aim of the present study was to optimize and evaluate the potential of novel technological interventions in the production of ready-to-eat Irish edible crab (Cancer pagurus). The Thesis begins with a general overview of food preservation and main characteristics of edible crab including its significance for the Irish seafood industry. An initial study characterized the main microbiota present in raw and ready-to-eat brown crab and their thermal resistance. Results obtained showed the importance of Bacillus spp. and Staphylococcus spp. in these products. Characterisation of bacterial thermal resistance proved the effectiveness of recommended heat treatments to inactivate Listeria monocytogenes (F70°C7.5°C = 2 minutes). However, the study also revealed that the most severe heat treatment currently recommended, which has Clostridium botulinum non-proteolytic type E as a target microorganism (F90°C8.6°C = 57 minutes), is not sufficient to achieve a comparable inactivation (i.e. 6 Log10 cycles) of the most heat resistant bacterial spore isolated from crab samples namely, Bacillus weihenstephanensis. Following the microbial characterization studies, the potential for incorporating ultrasound to improve early stages in ready-to-eat crab production (i.e. the initial cooking step) was evaluated. The application of ultrasound during cooking enhanced the rate of heat transfer, allowing up to a 15% reduction in total cooking time. In addition, ultrasound also proved its efficacy for enhancing mass transfer from the crab to the cooking water. This improved crab cleaning during cooking would in turn allow the omission of the normal post cook cleaning process prior to packaging. Ultrasounds potential to enhance mass transfer from crab to the cooking water also prompted an investigation into its possible use to remove cadmium from crab. Results showed that ultrasound combined with mild temperatures has the capability to reduce the total cadmium content in edible crab by up to 22.8%. The results open the possibility for using ultrasound as alternative to resolve this issue for the crab industry. Following these studies the second heat treatment step (i.e. in-pack pasteurization) of ready-to-eat crab was optimized to minimize the impact of the treatment on the quality of the final product. Results showed that the colour of crab white meat was the parameter most affected by the heat treatment and therefore, a colour change kinetic for these heat induced changes was developed and used as a quality indicator for process optimization. Based on this study an optimal set of treatment conditions were proposed for the inactivation of C. botulinum non-proteolytic type E. However, based on the models developed the required heat treatment for a process which is solely thermal, would be too severe to retain a good quality. This situation would be further aggravated by the requirement for even more severe heat treatments if B. weihenstephanensis is considered as the target microorganism. Therefore, the use of alternative technologies (i.e. mano-sonication, mano-thermo-sonication and electron beam ionizing radiation) for the inactivation of the main bacterial spores isolated from brown crab was also evaluated. The use of ultrasound in combination with pressure and mild temperatures (i.e. Mano-Thermos-Sonication) showed a synergistic effect in terms of bacterial spore inactivation, which in turn would allow a reduction in the total processing time by over a 80% while still maintaining a similar level of inactivation to heat only. The use of irradiation also proved to be an effective technology to inactivate bacterial spores while still remaining below the limit of 10kGy established by WHO. In addition radiation was the technology least affected by changes in bacterial species or treatment media composition. Overall, the results of this thesis shows the potential for a number of alternative technologies and technical interventions to improve the processing of Irish edible crab and address present and future challenges in the production of these ready-to-eat products. <br /

Crab-meat-isolated psychrophilic spore forming bacteria inactivation by electron beam ionizing radiation

The present work was performed to evaluate the potential of electron beam ionizing radiation for the inactivation of three psychrophilic spore forming bacteria (Bacillus mycoides, Bacillus weihenstephanensis and Psychrobacillus psychrodurans) isolated from ready-to-eat brown crab (Cancer pagurus). Inactivation curves for the three spores were performed in both types of crab meat, brown and white. Also the effect of pH and water activity (aw) on the lethal efficacy of ionizing radiation, for the three different psychrophilic spore forming bacteria, was evaluated. The effects of pH, aw and their possible interactions were assessed in citrate-phosphate buffers of different pH, ranging between 7 and 4, and aw, ranging from 0.99 and 0.90, while an aw reduction from 0.90 to 0.80 had a minor impact on their resistance. In contrast to aw, the effect of pH showed a greater variability depending on the spore species. While pH did not affect the resistance of B. weihenstephanensis at any aw, B. mycoides showed slightly higher resistance at pH 5.5¿at aw of 0.90 and 0.80. pH showed a significant effect on the resistance of P. psychrodurans. For the two types of crab meat, slightly differences were observed in 6D values. B. weihenstephanensis was the most resistant, requiring 7.3–7.6¿kGy to inactivate 6 Log10-cycles of this spore forming bacterium, while for B. mycoides and P. psychrodurans 6.1–6.3 and 5.4–5.3¿kGy respectively were necessary to reach the same inactivation level in crab meat. An agreement between spore resistance in crab meats and lab media, with similar characteristics in pH and aw, was also observed. The results obtained in this research demonstrated the potential for ionizing radiation to achieve an appropriate inactivation level of spores naturally present in brown crab with the application of doses lower than 10¿kGy

Silicon microcantilever sensors to detect the reversible conformational change of a molecular switch, Spiropyan

The high sensitivity of silicon microcantilever sensors has expanded their use in areas ranging from gas sensing to bio-medical applications. Photochromic molecules also represent promising candidates for a large variety of sensing applications. In this work, the operating principles of these two sensing methods are combined in order to detect the reversible conformational change of a molecular switch, spiropyran. Thus, arrays of silicon microcantilever sensors were functionalized with spiropyran on the gold covered side and used as test microcantilevers. The microcantilever deflection response was observed, in five sequential cycles, as the transition from the spiropyran (SP) (CLOSED) to the merocyanine (MC) (OPEN) state and vice-versa when induced by UV and white light LED sources, respectively, proving the reversibility capabilities of this type of sensor. The microcantilever deflection direction was observed to be in one direction when changing to the MC state and in the opposite direction when changing back to the SP state. A tensile stress was induced in the microcantilever when the SP to MC transition took place, while a compressive stress was observed for the reverse transition. These different type of stresses are believed to be related to the spatial conformational changes induced in the photochromic molecule upon photo-isomerisation

Vascular responses to radiotherapy and androgen-deprivation therapy in experimental prostate cancer

Background: Radiotherapy (RT) and androgen-deprivation therapy (ADT) are standard treatments for advanced prostate cancer (PC). Tumor vascularization is recognized as an important physiological feature likely to impact on both RT and ADT response, and this study therefore aimed to characterize the vascular responses to RT and ADT in experimental PC. Methods: Using mice implanted with CWR22 PC xenografts, vascular responses to RT and ADT by castration were visualized in vivo by DCE MRI, before contrast-enhancement curves were analyzed both semi-quantitatively and by pharmacokinetic modeling. Extracted image parameters were correlated to the results from ex vivo quantitative fluorescent immunohistochemical analysis (qIHC) of tumor vascularization (9 F1), perfusion (Hoechst 33342), and hypoxia (pimonidazole), performed on tissue sections made from tumors excised directly after DCE MRI. Results: Compared to untreated (Ctrl) tumors, an improved and highly functional vascularization was detected in androgen-deprived (AD) tumors, reflected by increases in DCE MRI parameters and by increased number of vessels (VN), vessel density ( VD), and vessel area fraction ( VF) from qIHC. Although total hypoxic fractions ( HF) did not change, estimated acute hypoxia scores ( AHS) – the proportion of hypoxia staining within 50 μm from perfusion staining – were increased in AD tumors compared to in Ctrl tumors. Five to six months after ADT renewed castration-resistant (CR) tumor growth appeared with an even further enhanced tumor vascularization. Compared to the large vascular changes induced by ADT, RT induced minor vascular changes. Correlating DCE MRI and qIHC parameters unveiled the semi-quantitative parameters area under curve ( AUC) from initial time-points to strongly correlate with VD and VF, whereas estimation of vessel size ( VS) by DCE MRI required pharmacokinetic modeling. HF was not correlated to any DCE MRI parameter, however, AHS may be estimated after pharmacokinetic modeling. Interestingly, such modeling also detected tumor necrosis very strongly. Conclusions: DCE MRI reliably allows non-invasive assessment of tumors’ vascular function. The findings of increased tumor vascularization after ADT encourage further studies into whether these changes are beneficial for combined RT, or if treatment with anti-angiogenic therapy may be a strategy to improve the therapeutic efficacy of ADT in advanced PC.publishedVersio

Efficacy of ultraviolet light (UV-C) and pulsed light (PL) for the microbiological decontamination of raw salmon (Salmo salar) and food contact surface materials

peer-reviewedThe decontamination effect of two light-based technologies on salmon, polyethylene (PE) and stainless steel (SS) was evaluated. Optimization of treatment conditions for ultraviolet light (UV-C) and pulsed light (PL) was carried out on raw salmon, obtaining inactivation levels of 0.9 and 1.3 log CFU/g respectively. The effects of treatments on several microbial groups present in salmon were then evaluated. For both technologies, Pseudomonas spp. were found to be the most resistant group of microorganisms tested. Three different strains from within this group were isolated and speciated, including a P. fluorescens strain which was selected for subsequent studies. PE and SS surfaces were inoculated with a suspension of the P. fluorescens suspended in a ‘salmon juice’ solution, and treated with UV-C and PL at different doses (mJ/cm2). PE surfaces were effectively decontaminated a low doses for both technologies, with a reduction of >4 log cycles observed. Decontamination of SS was also effective when treated with PL, although at higher doses than for PE. When SS was treated with UV-C, the maximum reduction of P. fluorescens achieved was 2 log cycles, even at the highest dose

Impact of pulsed electric field pre-treatment on nutritional and polyphenolic contents and bioactivities of light and dark brewer's spent grains

peer-reviewedPulsed electric field (PEF) pre-treatment, at 2.8 kV/cm with 3000 pulses of 20 μs pulse-width, was applied on brewer's spent grains (BSG) followed by aqueous extraction at 55 °C, 220 rpm for 16 h. PEF pre-treatment showed significantly increased yields (p 50 mg/mL) with lowest MIC value of 1.56 mg/mL against Staphylococcus aureus. All the BSG extracts induced the release of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) and chemokines (IL-8, MCP-1 and MIP-1α) confirming immunomodulatory activity.The authors acknowledge financial support from the ‘NovTechIng’ project funded under the Food Institutional Research Measure (Project No. FIRM/11/F/050) by the Irish Department of Agriculture, Food and Marine. The immunomodulatory study was performed using funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 634086 (NEPHSTROM). TPG is funded by a Hardiman Research Scholarship from the College of Medicine, Nursing and Health Sciences, National University of Ireland, Galway.The authors acknowledge financial support from the ‘NovTechIng’ project funded under the Food Institutional Research Measure (Project No. FIRM/11/F/050) by the Irish Department of Agriculture, Food and Marine. The immunomodulatory study was performed using funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 634086 (NEPHSTROM). TPG is funded by a Hardiman Research Scholarship from the College of Medicine, Nursing and Health Sciences, National University of Ireland, Galway

Edging your bets: advantage play, gambling, crime and victimisation

Consumerism, industrial development and regulatory liberalisation have underpinned the ascendance of gambling to a mainstream consumption practice. In particular, the online gambling environment has been marketed as a site of ‘safe risks’ where citizens can engage in a multitude of different forms of aleatory consumption. This paper offers a virtual ethnography of an online ‘advantage play’ subculture. It demonstrates how advantage players have reinterpreted the online gambling landscape as an environment saturated with crime and victimisation. In this virtual world, advantage play is no longer simply an instrumental act concerned with profit accumulation to finance consumer desires. Rather, it acts as an opportunity for individuals to engage in a unique form of edgework, whereby the threat to one’s well-being is tested through an ability to avoid crime and victimisation. This paper demonstrates how mediated environments may act as sites for edgeworking and how the potential for victimisation can be something that is actively engaged with

Mitochondrial dysfunction resulting from loss of cytochrome c impairs radiation-induced bystander effect

Cytochrome c is a pivotal protein that resides in mitochondria as component of mitochondria respiration and apoptosis initiator. Using murine cells lacking cytochrome c, we showed here that cytochrome c-deficient cells had attenuated reactive oxygen species/nitric oxide and micronuclei induction to radiation-induced bystander signals, indicating cytochrome c is essential for the bystander effect