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The impact of cold chain temperature abuses on the quality of frozen strawberri...

The quality of frozen foods can be negatively a ected if improper storage and distribution temperatures are allowed. The objective of this study was to investigate the e ect of freeze-thaw cycles, which may occur in the cold chain, on colour (Lab, Total Colour Di erences (TCD), chroma and hue angle) and vitamin C (ascorbic and dehydroascorbic acids) content of frozen strawberries (Fragaria ananassa, Duschesne,...

Impact of thermal blanching and thermosonication treatments on watercress (Nast...

The objectives of the present work were to optimise watercress heat and thermosonication blanching conditions, in order to obtain a product with better quality for further freezing, and to evaluate the effects of thermosonication on the microstructure of watercress leaves. In a chart of optimal time–temperature conditions for a 90% peroxidase inactivation (imposed constraint), vitamin C (objective function) and...

Enterococcus faecalis and pseudomonas aeruginosa behaviour in frozen watercress...

Watercress is an herb traditionally consumed fresh. If frozen, would be readily available to consumers. However, pathogenics resistant to frozen storage are a safety concern in this new product. In this study watercress was artificially contaminated with Pseudomonas aeruginosa ATCC 27853 and Enterococcus faecalis ATCC 29212. Their survival was evaluated after blanching, frozen storage and temperature fluctuatio...

The response of watercress (nasturtium officinale) to vacuum impregnation: Effe...

The setting up of methodologies that reduce the size of ice crystals and reduce or inhibit the recrystallisation phenomena could have an extraordinary significance in the final quality of frozen products and consequently bring out new market opportunities. In this work, the effect of an antifreeze protein type I (AFP-I), by vacuum impregnation (VI), on frozen watercress was studied. The VI pressure, samples’ we...

Effect of cold chain temperature abuses on the quality of frozen watercress (Na...

The objective of this work was to study the effect of temperature abuses on the colour and vitamin C content of a new frozen vegetable, watercress (Nasturtium officinale R. Br.). The vitamin C content, expressed as ascorbic (AA) and dehydroascorbic (DHAA) acids, and colour, expressed in the Hunter Lab parameters, were evaluated along a plan of temperature abuses, based on a real situation for a four month froze...

Effect of heat and thermosonication treatments on watercress (Nasturtium offici...

The use of ultrasound in food processing creates novel and interesting methodologies, which are often complementary to classical techniques. In this work, the effect of heat and the combined treatment heat/ultrasound (thermosonication) on the thermal degradation kinetics of vitamin C in watercress (Nasturtium officinale) was studied in the temperature range of 82.5 to 92.5 °C. First order reaction kinetics adeq...

Efeito dos abusos de temperatura no teor de ácido ascórbico em agrião congelado...

Este trabalho consistiu no estudo do efeito dos abusos de temperatura no teor de ácido ascórbico (AA) em agrião congelado ao longo da cadeia de distribuição. Para tal, simulou-se um conjunto de condições a que os produtos congelados são sujeitos desde a saída da fábrica até ao consumidor. O agrião, antes do processo de congelação, foi branqueado a uma temperatura de 95 ºC durante 20 s, para uma redução de 90% n...

Modelling kinetics of watercress (Nasturtium officinale) colour changes due to ...

Watercress (Nasturtium officinale) colour changes due to blanching by heat and a combined treatment of heat/ultrasound (thermosonication) were studied in the temperature range of 82.5 to 92.5 °C. The application of thermosonication was intended to enable less severe blanching treatments and, therefore, improve the quality of the blanched product. The thermosonication blanching processes promoted changes of the ...

Effect of heat and thermosonication treatments on peroxidise inactivation kinet...

The effect of heat and the combined heat/ultrasound (thermosonication) treatment on the inactivation kinetics of peroxidase in watercress (Nasturtium officinale) was studied in the temperature range of 40–92.5 C. In the heat blanching processes, the enzyme kinetics showed a first-order biphasic inactivation model. The activation energies and the rates of the reaction at a reference temperature for both the hea...

Processing zucchini (Cucurbita pepo L.) with low UV-C radiation