Browsing by Author "Machado, Ana"
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- Antioxidant and antimicrobial properties of PLA based active packaging with pomegranate peels and extractPublication . Andrade, Mariana; Rodrigues, Pedro; Barros, Carolina; Cruz, Vasco; Machado, Ana; Barbosa, Cássia; Coelho, Anabela; Furtado, Rosália; Correia, Cristina; Saraiva, Margarida; Vilarinho, Fernanda; Ramos, Fernando; Sanches Silva, AnaActive food packaging’ primary goal is to extend foodstuffs’ shelf life, through a dynamic and continuous interaction between the package and the packaged food. In an emission active packaging, the objective is the gradual release of antioxidant and/or antimicrobial compounds into the food surface, to delay the natural foods’ degradation. The active compounds can be extracted from several sources, such as aromatic plants, seaweeds, fruits by-products, among others. Since 50% of pomegranate is composed by peels, and since it is mainly consumed in juice and jam form, pomegranate peels may represent a considerable asset for the extraction of such compounds. The principal objective of this work was to evaluate the antioxidant and antimicrobial properties of polylactic-based active packaging incorporated with 3% (w/w) of pomegranate peels (PLA/3PP) and 3% (w/w) of pomegranate peels extract (PLA/3PPE). For the in vitro antioxidant activity evaluation, 9.08 cm2 of films were immersed in the food simulator, ethanol 95% (v/v), at 40 °C for 10 days. Then, the DPPH radical scavenging assay was performed, as well as the total content of phenolic compounds, total content in flavonoids, content in punicalagin (A+B) and ellagic acid were determined. Also, to fully determine the total content in punicalagin (A+B) and ellagic acid, the films were kept in methanol at 25 and 40 °C for 24 h. The antimicrobial activity of the films was evaluated with Listeria monocytogenes, Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli, in accordance with ISO 22196:2011. Results showed that PLA/3PPE presented a higher antioxidant potential and higher content in phenolic compounds and flavonoids. Only ellagic acid was detected in the active PLA-based films. Regarding the antimicrobial activity, both films presented antimicrobial activity against S. aureus.
- Extending beef meat shelf life: an approach using active food packaging with pomegranate extract and peelsPublication . Andrade, Mariana; Rodrigues, Pedro; Barros, Carolina; Cruz, Vasco; Machado, Ana; Barbosa, Cássia; Coelho, Anabela; Furtado, Rosália; Correia, Cristina; Saraiva, Margarida; Vilarinho, Fernanda; Ramos, Fernando; Sanches Silva, AnaMore than 50% of the pomegranate fruit (Punica granatum L.) is not considered edible, being composed by peels (50%) and seeds (10%). Pomegranate peels represent an excellent source of bioactive compounds with excellent antioxidant and antimicrobial activities due to the peels’ high content in phenolic compounds, specially punicalagin (A+B) and ellagic acid. The aim of the present study was to evaluate the potential effects of a polylactic acid (PLA) based active packaging incorporated with pomegranate peels and an ethanolic extract from pomegranate peels in the shelf-life extension of fresh meat. Two PLA-based active packaging incorporating 3% (w/w) of pomegranate peels (PLA/3PP) and 3% (w/w) of pomegranate peels extract (PLA/3PPE) were used to pack beef meat. The samples were stored at 4 °C, for a maximum of 11 days. The meats’ lipid oxidation and microbial contamination was evaluated at the end of 1, 4, 6, 8 and 11 storage days. Lipid oxidation was measured by the Thiobarbituric Acid Reactive Substances assay (TBARS)[1]. Meat’s total microorganisms count at 30 °C was performed using the automated method TEMPO® Aerobic Count- AFNOR BIO 12/35–05/13. Both PLA active packaging significantly delayed meat’s lipid oxidation and microbial growth. The meat with PLA/3PP and PLA/3PPE presented a difference up to 3 log CFU/g on the 11th storage day. Even though both active packaging were able to inhibit meat’s lipid oxidation, these results showed that PLA/3PP was more efficient, providing insights for the use of this bio-waste towards environmental sustainability.
- 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.