Scholarly record

NEW APPROACHES IN THE DEVELOPMENT OF BIOPOLYMERS BASED -MATERIALS USED FOR FOOD PACKAGING

Roxana Gheorghiță, Liliana Anchidin Norocel

Abstract

Lately, the food industry, along with other industries, is making efforts to prevent environmental pollution, by improving both processing-development and packaging technologies. Packaging used in the food industry usually uses synthetic, petroleum-based materials, such as polyethylene, polypropylene, polystyrene, etc. These materials are extremely polluting, and the raw materials are non-renewable. A beneficial solution in this regard is the development and use of biodegradable foil packaging that can successfully replace conventional materials. The present study verified the possibility of development an edible material used for the packaging of retail products. In this sense, 15 films, obtained entirely from natural substances, such as agar (0.5-3 g), alginate (0.5-3 g), glycerol (0.5-1 g) and water (150 ml) were developed, tested and characterized. These films are completely edible and biodegradable, eco-friendly and generates zero-waste. Obtained from different compositions, these materials were tested in order to identify the physical, optical, and mechanical properties as well as solubility capacity. In this regard, the visual appearance, microstructure, thickness, retraction ratio, color, transmittance, opacity, tensile strength, and elongation were evaluated. As the material used for the individual packaging of food products is consumed in their entirety, it must meet the criteria of microbiological safety. In this regard, the samples were tested using plates with dehydrated culture medium, specific for the total number of germs, enterobacteria, coliform bacteria, Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, and yeasts and molds. None of the tested microorganisms developed on the materials. In addition, the water activity index was determined. This is a parameter that has a role in the inhibition or proliferation of microorganisms. With extremely low values (0.3128 - 0.3968), this is a helpful factor in inhibiting the development of altering and pathogenic microorganisms. The thickness of the films varied between 36.40 ?m (sample with high content of alginate in the composition) and 72.20 ?m (sample with high content of agar in the composition). The retraction ratio is inversely proportional to the thickness, respectively 4.58% for the sample with maximum thickness and 51.89% for the sample with the lowest values of thickness. The maximum tensile strength (47.38 MPa) and elongation (92.10 %) were found in the samples with the lowest thickness. The results indicated the best characteristics in the films obtained from higher amounts of agar and lower amounts of alginate (agar: alginate ratio= 75:25). Also, good characteristics were identified for the sample with equal content of biopolymers. According to the results of the experiment, these materials are an alternative that can successfully replace the packaging currently used, especially since their characteristics are similar to those of conventional packaging. Furthermore, in order to improve the nutritional and sensory characteristics, the films can be incorporated with various other natural substances such as natural powders, fruits or vegetable purees, and edible essential oils.

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DOI resolver: doi.org/10.5593/sgem2021/6.1/s25.26

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