New Active Packaging Based on Biopolymeric Mixture Added with Bacteriocin as Active Compound

Abstract

The objective of this work was to develop a chitosan/agar-agar bioplastic film incorporated with bacteriocin that presents active potential when used as food packaging. The formulation of the film solution was determined from an experimental design, through the optimization using the desirability function. After establishing the concentrations of the biopolymers and the plasticizer, the purified bacteriocin extract of Lactobacillus sakei was added, which acts as an antibacterial agent. The films were characterized through physical, chemical, mechanical, barrier, and microbiological analyses. The mechanical properties and water vapor permeability were not altered by the addition of the extract. The swelling property decreased with the addition of the extract and the solubility increased, however, the film remained intact when in contact with the food, thus allowing an efficient barrier. Visible light protection was improved by increased opacity and antibacterial capacity was effective. When used as Minas Frescal cream cheese packaging, it contributed to the increase of microbiological stability, showing a reduction of 2.62 log UFC/g, contributing a gradual release of the active compound into the food during the storage time. The film had an active capacity that could be used as a barrier to the food, allowing it to be safely packaged.

Agar-Agar and Chitosan as Precursors in the Synthesis of Functional Film for Foods: A Review

“…The Agar-agar films allow easy interaction with mainly aqueous bioactive extracts. In film synthesis, when the solvent is replaced by an aqueous extract, it allows a homogeneous interaction with the agar-agar matrix [63]. Due to the high compaction of pure agar film, it becomes very brittle.…”

“…The electrostatic interaction is caused by the -NH 3+ groups of chitosan and -COO − of the ester group of agar-agar [64] in addition to intermolecular interactions through hydrogen bonds between functional groups, such as -OH [65] (Figure 2). The bond between the polymers allows synthesis of a homogeneous film that combines the benefits of both, depending on the concentrations used and the presence or absence of extracts, resulting in materials with particular properties [63]. Cao et al [66] used different concentrations of agar-agar and chitosan, and found th when the proportions of the polymers were equal the permeability to water vapor w reduced.…”

“…This effect is caused by the total interaction between the hydroxyls (-OH) of agar and chitosan, leaving no free hydroxyls to interact with water. In agar-agar and chitosan blends, the lower the concentration of agar in the mixture, the greater the elongation of the material; the agar absorbs moisture from the environment, reducing the bond with chitosan; the resulting polymer allows greater mobility of the film, increasing its elongation to break [63].…”

“…The current literature presents few reports of chitosan and agar-agar blends in their ground state, other than in the form of nanocomposites or other complexes, and even these are limited [63,[66][67][68]. The combination of these polymers without any treatment with solvents allows the synthesis of a totally green film without any impact on the environment.…”

Bio-Based Materials for Packaging

“…The application of these materials in the production of antimicrobial food packaging containing clay and silicate-, biopolymer-, metal-, nanocellulose-, and layered double hydroxide-based bio-nanocomposites was also described. An additional research article by Contessa et al [ 21 ], entitled “New Active Packaging Based on Biopolymeric Mixture Added with Bacteriocin as Active Compound”, described a chitosan/agar-agar bioplastic film incorporating bacteriocin extracted from Lactobacillus sakei as an antibacterial agent. When used for Minas Frescal cream cheese packaging, this material was shown to contribute to a significant increase in cheese microbiological stability, releasing the active compound into the food during its storage.…”