Embalagem ativa com fibra de colágeno e óleos essenciais para acondicionamento de produtos cárneos

Abstract

The excessive use of non-biodegradable fossil-based polymers and food waste affect the environment. Biopolymers that can be extracted from industry by-products such as collagen fiber can be exploited for the production of biodegradable films. New technologies can be applied in packaging in order to increase the safety, quality and shelf life of food, where active packaging is the answer to this demand. This study aimed at the development of biodegradable films of collagen fiber and polyvinyl alcohol, adding the essential oils of oregano and rosemary in the matrix of the films, and later applying them as active packaging in a sliced meat product. Through the analysis of minimum inhibitory concentration, minimum bactericidal concentration and micro-atmosphere of the essential oils, the bacteria Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Listeria monocytogenes (forming biofilm) and Listeria monocytogenes (Scott A), were more susceptible to oregano essential oil. Films based on collagen fiber and polyvinyl alcohol were developed with the addition of 0, 2, 4 and 6% oregano or rosemary essential oil. The films showed antimicrobial activity by disk-diffusion and micro-atmosphere methods against six strains of pathogenic bacteria. Comparing the two essential oils, different behaviors were observed, higher levels of essential oil of oregano to initiate the inhibition of the bacteria Staphylococcus aureus, Escherichia coli and Listeria monocytogenes (Scott A) was necessary, but with the increase in the oil level, they presented the highest inhibitions. For the micro-atmosphere analysis, the bacteria showed a similar behavior, however greater activities were observed for the essential oil of oregano. The incorporation of essential oils promoted physical, structural, optical and mechanical changes in the films. For color, there was a tendency towards greenish-yellow, opacity increased, but brightness (L*) was unaffected. The surface of the films showed differences comparing the oils, these differences can be explained due to the composition of the oils. Greater flexibility of the films was verified with the increase of the essential oil level, due to the greater elongation of the films rupture. Greater inhibition of the DPPH radical was verified for the films with the essential oil of oregano and through the analysis of main compounds it was observed that the films with the addition of the essential oil of oregano presented greater antioxidant activity not only due to the presence of the compounds carvacrol and thymol, but mainly to γ-terpinene and p-cymene. The application of the films as active packaging was performed on sliced meat product, where there were no differences (p>0.05) by the type of essential oil, but by the level (p<0.05) for the parameters of moisture, activity of water, pH and E. coli count. Greater loss of water activity in mortadella was observed on the 9th day of storage for packages with 0 and 6% essential oil. Lower lipid oxidation was observed for packaging with oregano essential oil. Regarding the results, the essential oil of oregano (levels 2 and 4%) proved to be a good alternative for application as a packaging for sliced meat products.