Browsing by Author "Marmelo, Isa"
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- In vitro bioaccessibility of macro and trace elements in biofortified and conventional farmed gilthead seabream (Sparus aurata) and common carp (Cyprinus carpio)Publication . Barbosa, Vera; Anacleto, Patrícia; Maulvault, Ana Luísa; Oliveira, Helena; Marmelo, Isa; Ferraris, Francesca; Raggi, Andrea; Ventura, Marta; Sobczak, Małgorzata; Eljasik, Piotr; Panicz, Remigiusz; Tsampa, Kalliopi; Karydas, Andreas G.; Carvalho, Maria Luisa; Martins, Marta; Cubadda, Francesco; Marques, AntónioBiofortification is a promising strategy to improve the nutrient profile of farmed fish but requires consideration of the nutrient bioaccessible fraction. In this study, the in vitro bioaccessibility of macro and trace elements was investigated in biofortified and conventional farmed gilthead seabream and common carp, also taking into account the effect of cooking (by steaming). Biofortification enhanced iodine and selenium levels in seabream and carp fillets. Steaming increased iodine and selenium contents in biofortified seabream, and increased selenium and decreased copper levels in biofortified carp. Higher iodine bioaccessibilty (> 80%) was observed in biofortified seabream compared to biofortified carp (45%). In both species, selenium, iron, and zinc bioaccessibility was ≥ 70%. Upon steaming iodine and iron bioaccessibility decreased in seabream, while selenium bioaccessibility decreased in carp. The consumption of steamed biofortified seabream and carp contributes to significantly higher daily intakes of iodine (up to 12% and 10%, respectively) and selenium (up to 54% and above 100%, respectively) compared to conventional counterparts. The present study demonstrates the potential of developing innovative biofortified farmed fish using natural sustainable feed ingredients to improve the intake of important nutrients for human health.
- Production and characterization of protein-rich extracts from the red macroalga Gelidium corneum and its industrial agar extraction residuesPublication . Mateus, Marília; Mão de Ferro, Rita; Pinheiro, Helena M.; Machado, Remígio; R. da Fonseca, M. Manuela; Sapatinha, Maria; Pires, Carla; Marmelo, Isa; Marques, António; Nunes, Maria Leonor; Motta, Carla; Cesário, M. TeresaThe red macroalga Gelidium corneum is a species commercially exploited for agar extraction, though with enormous potential for other industrial applications. This work aimed to produce protein-rich extracts from the crude alga and from residues of the industrial agar extraction process by applying different extraction and recovery procedures, and to characterize the obtained protein extracts. The sequential implementation of two water extractions followed by two alkaline extractions resulted in the recovery of 12.0 ± 1.2 % and 15.4 ± 0.9 % of the total protein contents of the crude alga and industrial residues, respectively. Two sequential water extractions assisted by Celluclast® and Alcalase® enzymes followed by two alkaline extractions recovered 52.1 ± 1.7 % and 36.5 ± 1.3 % of the protein contents of the crude alga and industrial residues, respectively. Extracts produced by these processes were characterized focusing on proximal composition, protein accessibility, nutrition and antioxidant potential, showing value as aquaculture feed ingredients. As all protein products revealed high carbohydrate contents and, aiming at enriching protein content, different protein precipitation methods were assessed, namely through ammonium sulfate precipitation and pH-shift protocols. The pH-shift method in sequential mode proved to be simple and fast with low reagent consumption. The purification of extracts by this precipitation mode allowed precipitating up to 72 % of the extracted protein. The results obtained suggest that protein concentrates extracted from Gelidium corneum appear to be promising sustainable sources for fish feed production, owing to their essential amino acid content, protein bioaccessibility and antioxidant properties.