Desenvolvimento de uma blenda biodegradável à base de celulose bacteriana (cb) e polihidroxibutirato (phb) para aplicação como embalagem ativa para alimentos.

Abstract

The increasing need for environmental preservation increases and intensifies the use of renewable resources in obtaining polymer films as packaging to maintain and / or improve food quality. In this context, blends based on cellulose polymers and polyhydroxyalkanoates (PHA) are potential candidates for this purpose due to the properties of biodegradability and biocompatibility. Cellulose is one of the most abundant natural polymers on earth and is mainly produced by plants, although many bacteria, especially those belonging to the genus Gluconacetobacter, produce a very peculiar form of cellulose with mechanical and structural properties that can be exploited in numerous industrial applications. Polyhydroxybutyrate (PHB), in turn, is a biodegradable bacterial polymer with thermoplastic properties that make it a potential candidate for the substitution of non-degradable polymers. In this sense, BC membranes were initially produced by the bacterium Gluconacetobacter hansenii UCP 1619 using standard Hestrin-Schramm (HS) modified medium containing 1.5% glucose and 2.5% corn steep liquor. After purification of the BC membrane, a BC and PHB-based blends was prepared from the combination of pure BC membranes with 30% PHB in acetic acid. Then the clove essential oil was added as an antimicrobial agent. The blends were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermal analysis and mechanical testing. Scanning electron microscopy revealed a homogeneous coating of the BC surface by deposition of PHB. The new blends can find important applications, since better mechanical properties were observed in front of the pure BC membrane. Studies of permeability, flexibility, retention and water absorption were also performed. The addition of the essential oil substantially reduced the microbial growth and better mechanical properties in the blend were observed against the pure BC membrane. The new material, composed of a BC and PHB blend, added with clove oil can find important applications as an active food packaging, considering the attractive properties of the blend and its biodegradable nature, as a biocompatible and efficient packaging for industrial use in the food industry.