Browsing by Author "Botelho, M. L."
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- Evaluation of potential of gamma radiation as a conservation treatment for blackberry fruitsPublication . Oliveira, M. M.; Pereira, J.; Cabo Verde, S.; Basto de Lima, Maria Gabriela; Pinto, Paula; Oliveira, P.B.; Junqueira, C.; Marcos, H.; Silva, T.; Melo, R.; Santos, C.N.; Botelho, M. L.BACKGROUND: Blackberries consumption has been associated with health benefits. However, these fruits present a short shelf-life. Thus, food irradiation is a potential alternative technology for conservation of these fruits without use of chemicals. OBJECTIVE: Analyse the potentiality of gamma radiation as a decontamination method for blackberry fruits. METHODS: Fresh packed blackberries were irradiated in a Co-60 source at two doses (1.0 and 1.5 kGy). Bioburden, physical and rheological, sensorial and total soluble content parameters were assessed before irradiation, immediately after and at two days storage time at 4°C. RESULTS: The characterization of blackberries microbiota point out to an average bioburden value of 104 CFU/g and to a microbial population predominantly composed by filamentous fungi. The inactivation studies on the blackberries mesophilic population indicated a limited microbial inactivation (<1 log decimal reduction) for the applied radiation doses, being the surviving population mainly constituted by filamentous fungi and yeast. No effect of irradiation on colour of blackberries was observed. Concerning texture parameters, no significant differences were observed in both fracturability and firmness between non-irradiated and irradiated blackberries immediately after irradiation. In blackberries stored for two days, both parameters were slightly lower in irradiated blackberries, compared to non-irradiated blackberries. The performed sensorial analysis indicated a similar acceptability among irradiated and non-irradiated fruits. CONCLUSION: This work reveals gamma irradiation treatment potential since no major impact was detected on blackberries physical, rheological and sensory attributes. Further studies with longer periods of storage are needed to elucidate the advantages of irradiation as a conservation treatment.© 2013 - IOS Press and the authors. All rights reserved.
- Impacto da radiação ionizante na viscosidade dos ovosPublication . Ribeiro, R.; Basto de Lima, Maria Gabriela; Nunes, P.; Cabo Verde, S.; Botelho, M. L.
- Impacto de agentes letais (calor húmido e radiação ionizante) no valor nutricional de ovos e ovoprodutosPublication . Sousa, L.; Cabo Verde, S.; Pinto, Paula; Santana, Antonieta; Dinis, Manuela; Botelho, M. L.A conservação de alimentos requer não só a manutenção de índices microbianos dentro de limites de segurança, como também a conservação das qualidades nutricionais e organolépticas. O tratamento de alimentos com radiação ionizante (raios gama) surge como um meio de conservação alternativo e seguro que pode aumentar as condições higieno-sanitários dos alimentos, nomeadamente os ovos, os quais parecem ter um papel importante na transmissão de salmoneloses ao ser humano. Neste estudo pretendeu-se avaliar o efeito de diferentes doses de irradiação (0,5, 2 e 5 kGy) no valor nutricional de ovos e ovo-produtos e comparar com o efeito do tratamento por calor (pasteurização). Foi também estudada a inactivação microbiana dos contaminantes naturais do ovo. Os resultados sugerem 1,5 kGy como a dose suficiente para assegurar a descontaminação dos ovos inteiros. Com esta dose de irradiação não parece haver degradação de proteínas nem alteração de fosfolípidos e ácidos gordos dos ovos e ovo-produtos.
- Sanitation of chicken eggs by ionizing radiation: functional and nutritional assessmentPublication . Pinto, Paula; Ribeiro, R.; Sousa, L.; Cabo Verde, S.; Basto de Lima, Maria Gabriela; Dinis, Manuela; Santana, Antonieta; Botelho, M. L.Alternative technologies must be developed and implemented considering sanitation and preservation of eggs mainly for risk population. Food irradiation is an alternative to free Salmonella spp. and Campylobacter spp. eggs, as a low dose point to a safety assurance. This study presents the correlation between irradiation doses (0.5 kGy up to 5 kGy at dose rate of 1.0 kGy/h) and some of functional and nutritional egg properties. Viscosimetry of non-irradiated and irradiated eggs was evaluated by means of VT550 Haake with an NV sensor and co-axes cylinders. After irradiation at 5 kGy, the yolk colour die (pale yellow) and the white egg was modified to a turbid yellow. The Cross equation was utilized to viscosimetry curves. Based on the assymptotics viscosimetry data indicated that increase of doses corresponds to an increase of the yolk and a decrease of white egg viscosimetry as such a Newton behaviour. Irradiation effects on nutritional properties were evaluated by means of egg protein patterns that were assessed by polyacrylamide gel electrophoresis. Lipids were identified by TLC. Based on results the sanitation dose is lower than the limit dose for the decrease of the main eggs properties.