Percorrer por autor "Rocha, Ada M. C. N."
A mostrar 1 - 10 de 15
Resultados por página
Opções de ordenação
- a* values to follow lycopene concentration during ripening and storage of tomato (cv. Caruso)Publication . Schauwers, Axelle; Rocha, Ada M. C. N.; Morais, Alcina M. M. B.The ripening of tomato fruit is a highly regulated process during which colour, flavour, aroma and texture change in a coordinated manner. This research work aims to correlate the colour changes measured objectively with the lycopene concentration in tomatoes during ripening at room temperature (21 and 26°C). These results were compared with colour and lycopene content of pink and light red tomatoes stored at 14°C, temperature used to prevent ripening and therefore extend the shelf life of the fruits. The duration of heat treatment at 100ºC was previously optimized in order to release the maximum lycopene from chromoplasts during extraction. An a* value of 20 for the peel corresponds to an increase of lycopene content of Caruso tomato from 9 to 43 mg/100 g TSS, at room temperature. The shelf life of pink and light red tomatoes can be extended to two weeks at 14ºC without loss of lycopene content, presenting the same content as green tomatoes ripened at room temperature for one week.
- Characterisation of ‘Starking’ apple polyphenoloxidasePublication . Rocha, Ada M. C. N.; Cano, M. Pilar; Galeazzi, Maria A. M.Experiments were performed to optimise the extraction conditions of “StarkingÏ apple fruit polyphenoloxidase (PPO), to evaluate the affinity and speciÐcity towards several substrates and to study the stability of enzyme extracts from apple samples stored under di†erent conditions. Sodium phosphate bu†er (0É2 M, pH 6É5) plus 0É25% Triton X and 1% or 2% PVPP was found to be the most efficient extraction mediu10m0. Chlorogenic acid, dopamine and 4- methylcatechol showed similar speciÐcity towards PPO, and chlorogenic acid was found to be the best substrate for the enzyme. Enzyme extracts from frozen cut apple stored at [4¡C, and extracts from lyophilised apple samples stored at 4¡C were more stable than extracts obtained from fresh-cut or acetone powder samples
- Cientistas estudam batata embalada sob vácuoPublication . Rocha, Ada M. C. N.; Morais, Alcina M. M. B.
- Efeito do armazenamento sob vácuo na actividade da PPO e nos compostos fenólicos da cenoura descascada (cv. Nantes)Publication . Rocha, Ada M. C. N.; Mota, Catarina; Morais, Alcina M. M. B.Os produtos MP são apresentados ao consumidor convenientemente descascados, descaroçados ou cortados em embalagens adequadas, com características de produto fresco e prontos a utilizar sendo, no entanto, mais perecíveis do que o seu equivalente fresco. O armazenamento sob vácuo constitui uma alternativa promissora para uma grande variedade de produtos. Neste estudo, propomo-nos a avaliar o impacto do processamento mínimo nos atributos de qualidade da cenoura (var. Nantes). A cenoura foi descascada, lavada, embalada sob vácuo e ao ar e armazenada a 4°C sendo, posteriormente, avaliada em relação ao teor de compostos fenólicos e actividade da polifenoloxidase. Quando, comparado com o embalamento ao ar, o embalamento sob vácuo parece ter um ligeiro efeito benéfico no teor de compostos fenólicos que, embora não perceptível pelo consumidor, afecta a qualidade do produto.
- Efeito do armazenamento sob vácuo na actividade da PPO e nos compostos fenólicos da cenoura descascada (cv. Nantes)Publication . Rocha, Ada M. C. N.; Mota, Catarina; Morais, Alcina M. M. B.
- Effect of vacuum packaging in nutritional quality of minimally processed potatoPublication . Rocha, Ada M. C. N.; Morais, Alcina M. M. B.; Coulon, Emilie C.
- Effects of minimal processing and temperature on respiration rate of carrot (cv. Nantes)Publication . Rocha, Ada M. C. N.; Mota, Catarina; Morais, Alcina M. M. B.
- Effects of vacuum packaging on the physical quality of minimally processed potatoesPublication . Rocha, Ada M. C. N.; Coulon, Emilie C.; Morais, Alcina M. M. B.In recent years, consumers have become more health conscious in their food choices but they also have less time to prepare healthy meals. As a result, minimally processed (MP) products have become an important sector of the food industry because of their ‘fresh-like’ qualities, convenience and speed of meal preparation. In this study, the physical qualities of MP potatoes (‘Désirée’ variety) stored for 7 days in vacuum packaging were evaluated. The shelf life of MP potatoes was effectively extended to nearly 1 week under refrigerated storage by using vacuum packaging systems. The main quality parameters were constant during storage.
- Influence of chemical treatment on polyphenoloxidase activity while related to colour changes of minimally processed ‘Jonagored’ applePublication . Rocha, Ada M. C. N.; Morais, Alcina M. M. B.
- Influência das condições de armazenamento na qualidade de kiwi minimamente processadoPublication . Rocha, Ada M. C. N.; Drieghe, Koen; Morais, Alcina M. M. B.