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Browsing by Author "Bertrand, Charlotte"

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  • Effects of different edible coatings on polyphenol oxidase activity and colour of fresh-cut apple during cold storage
    Publication . Bertrand, Charlotte; Raposo, Maria Filomena de Jesus; Morais, Rui Manuel Santos Costa de; Morais, Alcina Maria Miranda Bernado de
    Fresh-cut fruits are highly susceptible to enzymatic browning. The aim of this study was to evaluate the effects of different coatings on polyphenol oxidase (PPO) activity and colour of ‘Royal Gala’ apple cubes during storage at 4°C. The main constituents (polysaccharides) of the coatings used were carrageenan, alginate, the exopolysaccharide (EPS) from the marine microalga Porphyridium cruentum, pectin, and carboxymethyl cellulose (CMC). When PPO activity increased, the apple cubes became browner (L* values decreased, and/or a* and/or b* values increased) for pectin, carrageenan, EPS 5 g.L–1 and CMC coatings. EPS coated apple cubes, in particular, did not present the best results in order to prevent the colour changes and to lower down PPO activity, but the results obtained were very similar to those of alginate. The coating based on pectin was the most recommended to preserve fresh-cut ‘Royal Gala’ apple closely followed by CMC.
    2015Journal article Restricted access Show more
  • Effects of the exopolysaccharide from Porphyridium cruentum coating on polyphenol oxidase activity and colour of fresh-cut banana during cold storage
    Publication . Bertrand, Charlotte; Raposo, Maria Filomena de Jesus; Morais, Rui Manuel Santos Costa de; Morais, Alcina Miranda Bernardo de
    Fresh-cut fruits are highly susceptible to enzymatic browning. The aim of this study was to evaluate the effects of the exopolysaccharide (EPS) from the marine microalga Porphyridium cruentum on polyphenol oxidase (PPO) activity and colour of ‘Cavendish’ banana slices during storage at 4°C. The banana slices became browner (L* values and/or chroma values decreased, and/or a* increased), while PPO activity of coated samples remained approximately constant throughout storage. EPS 5 g.L–1 solution could be used as a coating to prevent the browning of ‘Cavendish’ banana slices, although after six days of storage the results obtained on colour and PPO activity were very similar to those of carrageenan.
    2015Journal article Restricted access Show more