Browsing by Author "Cerqueira, Miguel"
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- Lipid oxidation inhibition through active polylactic acid films with rosemary and green tea extractsPublication . Andrade, Mariana; Barbosa, Cássia; Cerqueira, Miguel; Machado, Ana; Azevedo, Gabriela; Vilarinho, Fernanda; Sanches-Silva, Ana; Ramos, FernandoMore and more, consumers are demanding natural products with longer shelf-life. Extracts from rosemary (Rosmarinus officinalis L.) and green tea (Camellia sinensis L.) have high antimicrobial and antioxidant activities. These extracts can be incorporated into polymers produced from renewable sources, to produce active biopackaging. This concept intends to positively interact with packaged food, to inhibit the natural degradation of food, maintaining the quality of the packaged food and increasing its shelf-life. The antioxidant activity of food grade extracts from rosemary and green tea was evaluated and the total content in phenolic compounds and flavonoids was determined.
- Pla Films Loaded with Green Tea and Rosemary Polyphenolic Extracts as an Active Packaging for Almond and BeefPublication . Andrade, Mariana; Barbosa, Cássia; Cerqueira, Miguel; Azevedo, Ana Gabriela; Barros, Carolina; Machado, Ana Vera; Coelho, Anabela; Furtado, Rosália; Belo Correia, Cristina; Saraiva, Margarida; Vilarinho, Fernanda; Sanches Silva, Ana; Ramos, FernandoAbstract: The antioxidant capacity and the phenolic compounds of extracts from Green Tea and Rosemary was determined. RE presented a higher antioxidant capacity and higher content of TPC and flavonoids than GTE. While the main phenolic compounds identified in RE were carnosic acid, carnosol and rosmarinic acid, in GTE were catechin, epigallocatechin gallate, epicatechin, rutin and gallic acid. Active PLA films were prepared by the incorporation of GTE and RE at different percentages, followed by the evaluation of their properties. Afterwards, almonds and beef were selected as model foodstuff and packaged with active PLA films.PLA with 4 % of GTE presented a higher WVP and opacity, while PLA with 4% (w/w) of RE presented the highest O2 permeability. PLA with 2 and 4 % (w/w) of GTE presented the highest DPPH inhibition percentage and the highest total content in phenolic compounds and flavonoids at the end of 10 days (at 40 °C), in contact with a fatty food simulant. Regarding the almond packaged with the active films, PLA films with 2 and 4 % of RE were the most effective in the reduction of oxidation, allowing to obtain the lowest malonaldehyde (MDA) content and the lowest peroxides, at the end of 60 days of storage at room temperature. In addition, PLA with GTE and RE inhibited the formation of MDA content in beef stored for 11 days at 4 °C. This study shows that these PLA active packages can contribute for delaying lipid oxidation in foodstuffs with high fat content.
- Probiotic-loaded microcapsule system for human in situ folate production: Encapsulation and system validationPublication . Ramos, Philippe E.; Abrunhosa, Luis; Pinheiro, Ana; Cerqueira, Miguel; Motta, Carla; Castanheira, Isabel; Chandra-Hioe, Maria V.; Arcot, Jayashree; Teixeira, José A.; Vicente, António A.This study focused on the use of a new system, an alginate|Ɛ-poly-L-lysine| alginate|chitosan microcapsule (APACM), able to immobilize a folate-producing probiotic, Lactococcus lactis ssp. cremoris (LLC), which provides a new approach to the utilization of capsules and probiotics for in situ production of vitamins. LLC is able to produce 95.25±26 μg·L−1 of folate, during 10 h, andwas encapsulated in the APACM. APACMproved its capacity to protect LLC against the harsh conditions of a simulated digestion maintaining a viable concentration of 6 log CFU·mL−1of LLC. A nutrients exchange capacity test, was performed using Lactobacillus plantarum UM7, a high lactic acid producer was used here to avoid false negative results. The production and release of 2 g·L−1 of lactic acidwas achieved through encapsulation of L. plantarum, after 20 h. The adhesion of APACM to epithelial cells was also quantified, yielding 38% and 33% of capsules adhered to HT-29 cells and Caco-2 cells, respectively.