Publicação
Active packaging based on PLA - Green Tea Extract
| Resumo: | Over the years, plastic industry has been growing, and plastics are present in our daily basis. Synthetic polymers, due to their excellent properties (low cost, versatility, weight, among others), have been extensively used in a wide range of applications, especially in packaging production. Although the use of synthetic polymers has proven to be benefic, their accumulation in the environment has been one of the main causes of environmental issues, since they are extremely resistant to degradation. One of the alternatives for this problem has been the incorporation of biodegradable polymers of natural origin to replace synthetic polymers, in particular in the production of packages with a short life-cycle. At the same time, population growth and constant demand for quality, safety and healthy food products contributed to the development of new food packaging systems. The amount of food waste generated along the supply chain also played an important role in the development of these new systems. Thus, new approaches were developed in the manufacture of packaging, being active packaging one of these newer systems. This type of package interacts with the surrounding environment contributing to the preservation of foods’ properties and increasing their shelf-life. This dissertation was focused on the development of a material with application as active food packaging, based on polylactic acid (PLA), a biodegradable polymer, to which was added green tea extract (GTE), in order to confer antioxidant properties. The compatibility between PLA and GTE was evaluated by producing mixtures of both materials in the melt. After this compatibility study, films of the mixture were produced by using blown film extrusion. Different amounts of GTE were added to PLA to evaluate its influence on the films’ antioxidant capacity. The produced materials were analyzed by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR). The films’ mechanical properties were evaluated, as well as their antioxidant capacity and water-vapor barrier properties. The results showed that the addition of green tea extract confers antioxidant capacity to the films, which is dependent on the quantity of GTE added. It was observed that films containing GTE have lower thermal stability and mechanical properties when compared with films without GTE. Nevertheless, they showed improved water-vapor barrier properties. These films proved to be efficient in the preservation of food, including apple, potatoes and smoked salmon, inhibiting oxidative phenomena that result in their spoilage. |
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| Autores principais: | Cunha, Américo Domingos Gonçalves da |
| Assunto: | Active packaging PLA Green tea extract Antioxidant Biodegradable Embalagem ativa Extrato de chá verde Antioxidante Biodegradável |
| Ano: | 2017 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | Over the years, plastic industry has been growing, and plastics are present in our daily basis. Synthetic polymers, due to their excellent properties (low cost, versatility, weight, among others), have been extensively used in a wide range of applications, especially in packaging production. Although the use of synthetic polymers has proven to be benefic, their accumulation in the environment has been one of the main causes of environmental issues, since they are extremely resistant to degradation. One of the alternatives for this problem has been the incorporation of biodegradable polymers of natural origin to replace synthetic polymers, in particular in the production of packages with a short life-cycle. At the same time, population growth and constant demand for quality, safety and healthy food products contributed to the development of new food packaging systems. The amount of food waste generated along the supply chain also played an important role in the development of these new systems. Thus, new approaches were developed in the manufacture of packaging, being active packaging one of these newer systems. This type of package interacts with the surrounding environment contributing to the preservation of foods’ properties and increasing their shelf-life. This dissertation was focused on the development of a material with application as active food packaging, based on polylactic acid (PLA), a biodegradable polymer, to which was added green tea extract (GTE), in order to confer antioxidant properties. The compatibility between PLA and GTE was evaluated by producing mixtures of both materials in the melt. After this compatibility study, films of the mixture were produced by using blown film extrusion. Different amounts of GTE were added to PLA to evaluate its influence on the films’ antioxidant capacity. The produced materials were analyzed by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR). The films’ mechanical properties were evaluated, as well as their antioxidant capacity and water-vapor barrier properties. The results showed that the addition of green tea extract confers antioxidant capacity to the films, which is dependent on the quantity of GTE added. It was observed that films containing GTE have lower thermal stability and mechanical properties when compared with films without GTE. Nevertheless, they showed improved water-vapor barrier properties. These films proved to be efficient in the preservation of food, including apple, potatoes and smoked salmon, inhibiting oxidative phenomena that result in their spoilage. |
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