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- Enhancing oxidative stability of sunflower oil by supplementation with prickled broom (Pterospartum tridentatum) ethanolic extractPublication . Neves, Marta; Miranda, Andreia; Lemos, Marco F.L.; Silva, Susana; Tecelão, CarlaThis study aimed to evaluate the effect of ethanolic extract of Pterospartum tridentatum flowers in the stability of sunflower oil. The extract was characterized regarding to its antioxidant activity by the 2,2,1-diphenyl-1-picrylhydrazyl (DPPH) scavenging method (EC50 = 76.3 ± 2.6 μg/mL) and total phenolic content (200 ± 8 mg GAE/g). Extracts were added at 500 mg/L (E1) and 1,000 mg/L (E2), and after 30 days of storage at room temperature, E2 oil showed improved quality parameters,with a reduction of 22.4%,17.2%,and 45.6% in the values of acidity,peroxide,and p-anisidine, respectively.The extract also increased oil stability at 180 °C.After 27 hr, the acidity (0.216 ± 0.016 mg KOH/g) and the total oxidation value (TOTOX) (69.30 ± 0.26) values of E2 oil were significantly lower than the control. These results showed that P. tridentatum effectively improved the shelf-life and thermal stability of sunflower oil,being a promising source of antioxidants for edible oils processing.
- Preservation of fresh-cut Rocha Pear using Codium tomentosum extractPublication . Augusto, Ana; Miranda, Andreia; Crespo, Daniel; Campos, Maria J.; Raimundo, Délio; Pedrosa, Rui; Mitchell, Geoffrey; Niranjan, Keshavan; Silva, Susana F.J.Rocha is a Portuguese pear cultivar with high economic importance in the Portuguese Western Region. Degradative processes following its manipulation can quickly lead to product rejection, especially when sold as a freshcut product. The efficacy of a marine-based edible coating to inhibit superficial browning development in freshcut Rocha pear slices was investigated over a storage period of 15 days. The aqueous extract of Codium tomentosum, an edible green seaweed, was incorporated in an edible coating (0.5 g 100 mL -1) for fresh-cut Rocha pear. This novel treatment effect on the quality parameters of the pears was compared with a commercial coating currently used by industry and a control (dipping in deionised water). After 15 days storage at 4 ◦C, samples treated with the seaweed extract exhibited fewer colour changes and lower rates of superficial browning than control and commercial samples. Seaweed extract treatment was also observed to inhibit yeast and mould development, which may further contribute to shelf-life extension.
- Preservation of fresh-cut Rocha Pear using Codium tomentosum extractPublication . Augusto, Ana; Miranda, Andreia; Crespo, Daniel; Campos, Maria J.; Raimundo, Délio; Pedrosa, Rui; Mitchell, Geoffrey; Niranjan, Keshavan; Silva, Susana F.J.Rocha is a Portuguese pear cultivar with high economic importance in the Portuguese Western Region. Degradative processes following its manipulation can quickly lead to product rejection, especially when sold as a freshcut product. The efficacy of a marine-based edible coating to inhibit superficial browning development in freshcut Rocha pear slices was investigated over a storage period of 15 days. The aqueous extract of Codium tomentosum, an edible green seaweed, was incorporated in an edible coating (0.5 g 100 mL -1) for fresh-cut Rocha pear. This novel treatment effect on the quality parameters of the pears was compared with a commercial coating currently used by industry and a control (dipping in deionised water). After 15 days storage at 4 ◦C, samples treated with the seaweed extract exhibited fewer colour changes and lower rates of superficial browning than control and commercial samples. Seaweed extract treatment was also observed to inhibit yeast and mould development, which may further contribute to shelf-life extension.
- A pilot plant scale testing of the application of seaweed-based natural coating and modified atmosphere packaging for shelf-life extension of fresh-cut applePublication . Augusto, Ana; Miranda, Andreia; Costa, Leonor; Pinheiro, Joaquina; Campos, Maria J.; Raimundo, Délio; Pedrosa, Rui; Mitchell, Geoffrey; Niranjan, Keshavan; Silva, Susana F. J.Codium tomentosum hydroethanolic extract was obtained using a pilot solid–liquid extractor to validate the anti-browning functionality of the extract under industrial conditions. Fresh-cut apple slices were coated by immersion in: (1) a seaweed extract solution (0.5% w/v) and (2) a commercial coating, and the two sets of samples were compared with a control (immersion in water). Packaged samples were stored, under ambient and modified atmosphere conditions at 4°C. After 30 days of storage, the samples that were coated with the seaweed extract and packaged under modified atmosphere, demonstrated lower peroxidase activity and polyphenol oxidation when compared with the samples treated with the commercial additive. These results confirm, at pilot scale and under industrial production conditions, the efficacy of the seaweed extract as a bio-based substitute for the synthetic coatings, which are currently used to prevent browning in fresh-cut apples. Novelty impact statement Fresh-cut fruits are subjected to processing operations leading to a decrease in nutritional and organoleptic properties. It is therefore necessary to adopt strategies to delay the degradative processes. In this study, the efficacy of a pilot-scale production and industrial application of a coating formulated with Codium tomentosum seaweed extract has been established for the first time. This seaweed extract possesses the potential to prevent browning development in fresh-cut apples under industrial operating conditions.
- A pilot plant scale testing of the application of seaweed-based natural coating and modified atmosphere packaging for shelf-life extension of fresh-cut applePublication . Augusto, Ana; Miranda, Andreia; Costa, Leonor; Pinheiro, Joaquina; Campos, Maria J.; Raimundo, Délio; Pedrosa, Rui; Mitchell, Geoffrey; Niranjan, Keshavan; Silva, Susana F.J.Codium tomentosum hydroethanolic extract was obtained using a pilot solid–liquid extractor to validate the anti-browning functionality of the extract under industrial conditions. Fresh-cut apple slices were coated by immersion in: (1) a seaweed extract solution (0.5% w/v) and (2) a commercial coating, and the two sets of samples were compared with a control (immersion in water). Packaged samples were stored, under ambient and modified atmosphere conditions at 4°C. After 30 days of storage, the samples that were coated with the seaweed extract and packaged under modified atmosphere, demonstrated lower peroxidase activity and polyphenol oxidation when compared with the samples treated with the commercial additive. These results confirm, at pilot scale and under industrial production conditions, the efficacy of the seaweed extract as a bio-based substitute for the synthetic coatings, which are currently used to prevent browning in fresh-cut apples.
- Avaliação da estabilidade físico-química de óleo alimentar suplementado com extrato de carquejaPublication . Miranda, Andreia Raquel Feliciano; Tecelão, Carla Sofia Ramos; Silva, Susana Filipa JesusA prevenção da oxidação lipídica, uma das principais causas de degradação de óleos alimentares, pode ser efetuada pela adição de antioxidantes. A preocupação pelo consumo de alimentos mais saudáveis e isentos de aditivos sintéticos tem contribuído para a crescente procura de antioxidantes naturais provenientes de plantas, que possam substituir os antioxidantes sintéticos em óleos e gorduras alimentares. O presente estudo teve como objetivo avaliar o efeito da adição de extrato de carqueja (Pterospartum tridentatum), em concentrações diferentes (500 mg/kg e 1000 mg/kg), na estabilidade físico-química de óleo alimentar submetido a três ciclos de aquecimento (9 horas cada) a 180ºC e de óleo armazenado à temperatura ambiente durante 30 dias. O extrato de carqueja foi obtido por extração em etanol, tendo-se alcançado um rendimento de 60,2%±0,225. Determinou-se a capacidade antioxidante do extrato de carqueja por avaliação da capacidade de redução do radical 1,1-difenil-2-picrilhidrazil (DPPH) e pelo método de Folin-Ciocalteu. Os resultados demonstraram que o extrato tem uma atividade antioxidante de 61,7%±0,38 e um teor de compostos fenólicos de 22,4 mg de equivalentes de ácido gálico /g de extrato. A estabilidade físico-química do óleo alimentar foi estudada através da análise de diversos parâmetros, nomeadamente acidez, índice de peróxidos, índice de p-anisidina, absorvância no UV, índice de refração, cor e densidade. Os resultados evidenciaram um aumento de todos os parâmetros, com exceção da cor, ao longo do aquecimento do óleo bem como no seu armazenamento à temperatura ambiente. Este aumento foi mais relevante no óleo em processo de aquecimento uma vez que a 180ºC as reações de oxidação ocorrem mais rapidamente do que à temperatura ambiente. Observaram-se alterações mais acentuadas dos parâmetros físico-químicos no óleo sem extrato de carqueja comparativamente ao óleo suplementado com 500mg/kg e 1000mg/kg de extrato, comprovando-se o efeito do extrato de carqueja na redução da oxidação e, consequentemente, no aumento da estabilidade físico-química do óleo alimentar. O óleo suplementado com 1000mg/kg de extrato de carqueja revelou-se o mais estável à oxidação.