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- Innovating Portuguese Traditional Pastry – on the use of pasteurized egg yolk in “ovos moles”Publication . Fundo, Joana F.; Quintas, Mafalda A.; Brandão, Teresa R. S.; Silva, Cristina L. M.
- Effect of non-thermal methods on the safety of strawberries (Fragaria anannassa) and watercress (Nasturtium officinale)Publication . Alexandre, Elisabete M. C.; Santos, Dora M.; Fundo, Joana; Brandão, Teresa R. S.; Silva, Cristina L. M.
- Effect of ozone on the quality of fresh-cut green beans (Phaseolus vulgaris L.) and bell peppers (Capsicum annuum L.)Publication . Alexandre, Elisabete M. C.; Fundo, Joana; Santos, Dora M.; Brandão, Teresa R. S.; Silva, Cristina L. M.Ozone is a potent oxidant and disinfectant agent with multiple industrial applications. The efficacy of ozone treatments has been recognised in the sanitation of equipments and water disinfections. Recently, ozone started to be used as an innovative food processing technology that guarantees product safety. The objective of this work was to study the effect of ozone on the quality of fresh-cut green beans (Phaseolus vulgaris, L.) and green and red bell peppers (Capsicum annuum, L.). The quality factors analysed were enzyme (peroxidase) activity, colour and texture for green beans, and colour, texture and pH for bell peppers. Experiments were carried out in pilot equipment. An ozone generator was interconnected to a container filled with tap water. Ozone was continuously incorporated in water and its content was indirectly measured by potential difference. Green beans and bell peppers were cut in small portions. Samples were immersed in ozonated and non-ozonated water baths and removed after different times till a maximum of 180 minutes. Data from both treatments were compared by analysis of variance. For green beans, results showed that ozone treatment did not affect the colour, but significantly influenced texture (firmness) and peroxidase inactivation (at 7% significance level). After 40 minutes enzyme activity was reduced approximately 20%. This inactivation was verified for the rest of the sampling times. Ozone treatment affected pH and texture (fracturability) of red bell peppers (at 1% significance level). The other quality factors were not significantly influenced by ozone.
- Effect of ultrasonication, thermosonication and UV-C irradiation on the quality of strawberries (fragaria anannassa) and red bell peppers (capsicum annuum L.)Publication . Santos Pedro, Dora M.; Alexandre, Elisabete M. C.; Fundo, Joana F.; Brandão, Teresa R. S.; Silva, Cristina L. M.
- Effect of ozone on Listeria innocua in bell peppers (Capsicum annuum L.) and in contaminated waterPublication . Alexandre, Elisabete M. C.; Fundo, Joana; Santos, Dora M.; Brandão, Teresa R. S.; Silva, Cristina L. M.
- Influence of ozone pre-treatment on the quality of frozen strawberries (Fragaria ananassa D.)Publication . Alexandre, Elisabete M. C.; Fundo, Joana F.; Santos Pedro, Dora M.; Brandão, Teresa R. S.; Silva, Cristina L. M.
- Estudo do efeito de tratamentos não térmicos na segurança de alguns frutos e vegetaisPublication . Silva, Cristina L. M.; Brandão, Teresa R. S.; Santos, Dora M.; Fundo, Joana F.
- Influence of disinfectant technologies on red bell peppers safetyPublication . Silva, Cristina L. M.; Alexandre, Elisabete M. C.; Fundo, Joana F.; Santos, Dora M.; Brandão, Teresa R. S.
- Study of the effect of freezing on the visco-elastic properties of strawberriesPublication . Fundo, J.; Brandão, Teresa R. S.; Quintas, M.; Silva, C. L. M.The objective of this work was to study the influence of freezing on the visco-elastic properties of strawberries. Food structure plays an important role in food quality and functionality. It is important for the consumers to find an identical sensation when they eat a fresh strawberry and when the strawberry is defrosted. The visco-elastic properties of a food product are an indirect measure of its structure. Experimental measurements of these properties may correlate to changes on the physical attributes of the product. In this work, a dynamic mechanical analyser was used to assess changes on loss (E’’) and storage (E’) modulus, applying a compressive test with a Ø1.5 cm parallel plate geometry. Strawberries were acquired in a local market and frozen in a blast and fluidized bed freezer at –30 ºC for 1 hour. Samples were stored at –30 ºC in freezing chambers. Analyses were performed on fresh strawberries, after freezing and during storage. The samples were cut in small cylinders (1.5cm x 1.5cm) and left to relax during 1 hour at room temperature. Preliminary tests were performed in order to evaluate the linear visco-elastic region and the loss and storage modulus were determined. A dynamic frequency sweep test was also performed. Results showed that the behaviour of fresh strawberry sample varies significantly when compared with a defrosted sample. The influence of the storage still cannot be evaluated and is currently under study. Overall, it can be concluded that the freezing process greatly influenced the visco-elastic properties of the strawberries.
- Influence of disinfectant technologies on red bell peppers safetyPublication . Alexandre, Elisabete M. C.; Fundo, Joana F.; Santos Pedro, Dora M.; Brandão, Teresa R. S.; Silva, Cristina L. M.The development of innovative technologies, promoting fruits and vegetables safety to reduce the risk of related food-borne diseases, is an actual concern. Several sanitizing agents for washing fruits and vegetables may be used to reduce the risk of microbial contamination. Traditional washing technologies utilize chlorine and hydrogen peroxide as sanitizing agents for fresh produce. More recently, ozone is being used as an innovative food processing technology that guarantees product safety, also increasing shelf life of fruits and vegetables. Its main advantage, when compared to traditional disinfectant technologies, relies on its potent antimicrobial action and non-toxic products decomposition. The objective of this work was to study the effectiveness of three sanitizing agents (sodium hypochlorite - used in a commercial available solution AMUKINA, hydrogen peroxide and ozone in aqueous solutions), on the reduction of Listeria innocua inoculated on red bell peppers. Results showed that ozone treatment allowed bacteria reductions identical to the ones attained with the traditional disinfectant solutions. On average, aqueous ozone allowed a decimal reduction of 2 cycles in Listeria innocua counts.
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