Dados do Trabalho

Título

CAN MECHANICAL PROPERTIES OF ALGINATE FILMS BE IMPROVED BY ADDING PURPLE POTATO FLOUR?

Introdução

Bioplastics are materials made from natural polymers (i.e., polysaccharides or proteins) as a sustainable alternative to conventional petroleum-derived plastics, which can take years to degrade. Alginate is a polysaccharide that can form films with a good barrier to oil and oxygen due to its gelling properties. However, alginate-based films have poor mechanical properties, requiring the addition of compounds for improvement, such as bioactives, additives, and/or polymers. Purple potato flour is rich in starch, fiber, and anthocyanins, being able to functionalize bioplastics. Therefore, this work aims to improve the mechanical properties of the alginate film by adding purple potato flour.

Material e Métodos

After cleaning, the purple potato was freeze-dried and ground in mesh 52 to obtain the flour. The film was prepared using a solution of 2% (m/v) sodium alginate, 30% (m/m) glycerol, and distilled water. Concentrations of 0%, 3.5%, and 7% (m/v) of flour were added to the film-forming solutions, and the films were obtained by the casting technique after drying in an oven at 40 ºC/24 h, being named as FC, F1, and F2, respectively. After drying, the tensile strength and elongation at break properties of the films were characterized using a texturometer.

Resultados e Discussão

It was observed that the addition of flour to alginate films led to the development of materials with a reddish color due to the increased anthocyanin content in the matrix and that the FC tension of 6.67 MPa increased to 15.42 and 21.03 MPa in films F1 and F2, respectively. On the other hand, elongation was reduced from 8.83% of FC to 2.66% and 1.79% in films F1 and F2, respectively.

Conclusão

This behavior may be related to the fact that purple potato flour consists of starch and insoluble fibers, generating greater resistance to the material and less flexibility. Therefore, alginate films can have their mechanical properties modulated by the addition of purple potato flour, enabling the development of a biodegradable material with better packaging performances.