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Percorrer por autor "Alves, Vitor D."

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  • Effect of olive pomace extract application and packaging material on the preservation of fresh-cut royal gala apples
    Publication . Madureira, Joana; Melgar Castañeda, Bruno; Alves, Vitor D.; Moldão-Martins, Margarida; Margaça, Fernanda M.A.; Santos-Buelga, Celestino; Barros, Lillian; Verde, Sandra Cabo
    The efficiency of natural olive pomace extracts for enhancing the quality of fresh-cut apples was compared with commercial ascorbic acid and two different packaging films (biodegradable polylactic acid (PLA) and oriented polypropylene (OPP)) were tested. The composition of atmosphere inside the packages, the physicochemical parameters (firmness, weight loss and color), the microbial load, total phenolic content and antioxidant activity of fresh-cut apples were evaluated throughout 12 days of storage at 4 degrees C. After 12 days of refrigerated storage, a significant decrease in O-2 was promoted in PLA films, and the weight loss of the whole packaging was higher in PLA films (5.4%) than in OPP films (0.2%). Natural olive pomace extracts reduced the load of mesophilic bacteria (3.4 +/- 0.1 log CFU/g and 2.4 +/- 0.1 log CFU/g for OPP and PLA films, respectively) and filamentous fungi (3.3 +/- 0.1 log CFU/g and 2.44 +/- 0.05 log CFU/g for OPP and PLA films, respectively) growth in fresh-cut apples after five days of storage at 4 degrees C, and no detection of coliforms was verified throughout the 12 days of storage. In general, the olive pomace extract preserved or improved the total phenolic index and antioxidant potential of the fruit, without significant changes in their firmness. Moreover, this extract seemed to be more effective when combined with the biodegradable PLA film packaging. This work can contribute to the availability of effective natural food additives, the sustainability of the olive oil industries and the reduction of environmental impact. It can also be useful in meeting the food industries requirements to develop new functional food products.
    2023Artigo científico Acesso aberto Ver mais
  • In vitro shoot cultures of pterospartum tridentatum as an alternative to wild plants as a source of bioactive compounds
    Publication . Gonçalves, José Carlos; Coelho, Maria Teresa; Diogo, Maria da Graça; Alves, Vitor D.; Bronze, Maria Rosário; Coimbra, Manuel A.; Martins, Vitor Manuel Ramalheira; Moldão-Martins, Margarida
    The aim of this study was to evaluate the composition of aqueous extracts of in vitro shoot cultures and wild plants of Pterospartum tridentatum in order to promote the use of this plant material as a possible source of bioactive compounds. The extraction yield from wild plants compared with in vitro shoot cultures was lower. The total phenolic contents of in vitro shoots were significantly lower compared with those of wild plants. The phenolic profiles of in vitro shoots were very similar to those of wild plants, regardless of the source. However, taxifolin-6-C-glucoside, as well as rutin and isoquercitrin, were not present in extracts of in vitro shoots. An interesting result was the higher molar percentages of rhamnose and uronic acids detected in in vitro shoots compared with the wild plants, which can make the in vitro plant material very useful for obtaining these compounds.
    2018Artigo científico Acesso aberto Ver mais