Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- Production and Characterization of k-Carrageenan Films Incorporating Cymbopogon winterianus Essential Oil as New Food Packaging MaterialsPublication . Santos, Catarina; Ramos, Ana; Luís, Ângelo; Amaral, Maria EmíliaThe global production of synthetic plastics from petroleum-based raw ingredients exceeds 150 million metric tons. The environment is threatened by tons of plastic waste, thus endangering wildlife and the public’s health. These consequences increased the interest in biodegradable polymers as potential substitutes for traditional packaging materials. This study aimed to produce and characterize k-carrageenan films incorporating Cymbopogon winterianus essential oil, in which citronellal was determined to be the major compound (41.12%). This essential oil presented remarkable antioxidant activity, as measured through DPPH (IC50 = 0.06 ± 0.01%, v/v; AAI = 85.60 ± 13.42) and β-carotene bleaching (IC50 = 3.16 ± 0.48%, v/v) methods. The essential oil also showed antibacterial properties against Listeria monocytogenes LMG 16779 (diameter of inhibition zone = 31.67 ± 5.16 mm and MIC = 8 µL/mL), which were also observed when incorporated in the k-carrageenan films. Moreover, scanning electron microscopy showed the reduction of the biofilms of this bacterium, and even its inactivation, due to visible destruction and loss of integrity when the biofilms were created directly on the developed k-carrageenan films. This study also revealed the quorum sensing inhibition potential of Cymbopogon winterianus essential oil (diameter of violacein production inhibition = 10.93 ± 0.81 mm), where it could impede intercellular communication and, hence, lower violacein synthesis. The produced k-carrageenan films were transparent (>90%) and slightly hydrophobic (water contact angle > 90°). This work demonstrated the viability of using Cymbopogon winterianus essential oil to produce k-carrageenan bioactive films as new food packaging materials. Future work should focus on the scale-up production of these films.
- Development of k-carrageenan films incorporating Cymbopogon winterianus and Lavandula viridis essential oils for food packaging applicationsPublication . Santos, Catarina Filipa Cunha; Amaral, Maria Emilia da Costa Cabral; Luís, Ângelo Filipe SantosFrom the XX century onwards, the innovation of plastics brought a global revolution, playing a fundamental role in improving comfort and practicality and minimizing food waste. However, this breakthrough had substantial drawbacks, most notably widespread pollution. The growing recognition of the damage caused by plastics to the ecosystem has driven scientific research and the exploration of sustainable alternatives, with a particular focus on food packaging. In the context of this complicated and diverse challenge, the purpose of this investigation was to create and characterize k-carrageenan films containing essential oils of Cymbopogon winterianus and Lavandula viridis. The aim is to use these films to produce a biodegradable material that can extend the shelf life of packaged foods. The essential oils were chemically characterized to identify and quantify the total and predominant chemical compounds. The antioxidant and antimicrobial properties of the essential oils have also been studied. The major compound in C. winterianus essential oil is citronellal, which has significant antioxidant activity, as demonstrated by the DPPH• assay and the ß-carotene bleaching test. This essential oil performed well against Listeria monocytogenes LMG 16779, which suggests it has antibacterial properties. The main composition of L. viridis essential oil is 1,8- cineole, which performed well in the DPPH• evaluation and had lower values than the previous essential oil in the ß-carotene bleaching test. This essential oil showed a similar result to the previous one against the same strain for the antibacterial test. The antioxidant, antibacterial, barrier and physical properties were studied for the films produced. Changes in the composition of the films were evaluated using FTIR. Carrying out tensile tests on the samples allowed us to infer that the films incorporated with essential oils lost, in general, part of their resistance when compared to the control film. In terms of antioxidant tests, the results for DPPH• were satisfactory, but the results for C. winterianus were more promising in terms of ß-carotene, as less of it is needed to exert an antioxidant effect. In antibacterial tests, the layer of action by L. monocytogenes LMG 16779 is evident for both films. This result was validated with the anti-biofilm test, through the formation of biofilms on the surface of the films, subsequently visualized in the SEM, showing a clear reduction in the number of bacteria. Finally, a test was carried out in a food model, in which sliced cheese samples were packaged with the films produced, kept at 4ºC for 15 days, and then observed. The results showed that no visible signs of rot or mold were found in the cheese.