Título da Tese: Desenvolvimento de embalagens para melhoria de qualidade da carne

Orientador: Prof. Dr. Ivanor Nunes do Prado

 Data da Defesa: 20/02/2019



INTRODUCTION. The exhaustion of natural resources has attracted interest in the development of new products, such as biodegradable packaging. Coupled with this new trend, smart packaging contributes to food preservation and reduction of chemical preservatives. In order to meet industrial needs and reduce the problems arising from the use of non-biodegradable products, new alternatives for renewable materials have been studied. In this context, the present work was divided into two stages. The first was a new food packaging technology from the evaluation of a cover with addition of oatmeal aiming at maintaining the quality of tilapia fillets. The second step addressed the characterization of a paper (cellulose) coated with sodium alginate containing cinnamon essential oil (CEO). Physical, optical and mechanical properties were evaluated in addition to the effect on antioxidant activity, lipid oxidation and color of hamburgers prepared from ground beef. AIMS. Considering the interest in the new packaging materials, especially sodium alginate, due to its filmogenic properties, this work aimed to evaluate new ways of using this material in the protection and conservation of meat. It was also the objective of this research to characterize the packaging as to its physical, physical and optical properties. MATERIAL AND METHODS. For the first stage, fillets of tilapia were obtained from the fish farming unit of the State University of Maringá - Codapar, located in Maringá, Paraná. To obtain the samples, the fish (mean weight ± 600g) were slaughtered, emptied, pickled, cleaned and filleted in two pieces of approximately 100 g weight / part. Then, the fillet samples were packed in polyethylene bags and conditioned in a refrigerator (2 ± 1 °C) for 24 hours for subsequent treatments. The alginate solution was prepared by dissolving glycerol (1%) and alginate (2%) in distilled water at 70 °C under stirring for 15 min using an Ultra-Turrax homogenizer (IKA®-T10, USA). Subsequently, the oatmeal was added and the emulsion homogenized for 15 min and then cooled to 25 °C and used as a coating on the fillets. The steaks were left at room temperature for 15 minutes before application of the treatments, where they were immersed in alginate solution for 1 minute, allowed to drain from the excess coating for 1 minute, submerged in calcium chloride solution (2% w / v) for 30 sec for complexation the coating by and, finally, drained for another 1 minute. The treatments were defined as: CON - fillets without cover, AC - fillets with alginate coating, ACO1 - fillets coated with 1% oatmeal, ACO2 - fillets coated with 2% oatmeal and ACO3 - fillets coated with 3 % of oatmeal. Samples individually packed in plastic trays wrapped with retractable film and stored refrigerated (2 ± 1 ° C) in illuminated display case (12 h / day with 1200 lux fluorescent lamp), simulating market conditions. The treatments were performed in triplicate and the experiments were performed in duplicate. Samples were randomly withdrawn at 1, 5, 10 and 15 days storage for analysis. For the development of the second stage of the study, the filmogenic solutions were prepared by dissolving glycerol (1.5%) in water under magnetic stirring at 45 °C for 45 min, then the alginate (1%) was added and homogenized with (IKA®-T10, USA) at 8000 rpm for 10 min, after complete dissolution the mixture was cooled to 25 Â °C. Based on results obtained previously by the (0.1 percent) of cinnamon essential oil (0.1%) was added to obtain active solutions. In addition, for better dispersion of the oil in the solution, tween 80 (0.25% by weight of oil) was added. After the film-forming solutions reached room 10 temperature, they were then applied to sheets of food paper (GioPak butter paper, roll 30cm x 7.5m) by scattering, at an estimated rate of about 1mL of solution / 100cm2 of paper. The coated sheets were oven dried with forced circulation at 35 °C for 24 hours and then used as packaging for the burgers. Four treatments were evaluated: CON - uncoated paper; PAC - paper with alginate coating; PAC1 - paper with alginate coating and 0.1% CEO; PAC0.5 - paper with alginate coating and 0.05% CEO. The new packaging was characterized (mechanical, physical and optical properties) and its effect on antioxidant activity, lipid oxidation and color of hamburgers were evaluated on days 1, 3 and 7 of refrigerated storage at 4 ºC. The experimental design was entirely with four treatments and three replicates per treatment. The effectiveness of the coated papers was evaluated by analysis of variance using the general linear model (GLM) with SPSS (v.22.0) (IBM SPSS Statistics, SPSS Inc., Chicago, USA) for Windows. When the differences were significant, the Tukey test was performed, with statistical significance of P = 0.05. RESULTS AND DISCUSSION. For the initial study, we have that lipid oxidation increased (P <0.001) during the storage time for all treatments. However, the coated fillets AC, ACO1, ACO2 and ACO3 presented a smaller reduction when compared to the control (P <0.004), and the coating with 3% addition of oat flour was the most efficient. However, on the last day of evaluation (day 15) all values were similar (P> 0.05). On the other hand, the storage time did not change (P> 0.05) the L * values of the tilapia fillets. The a * values were negative. However, the ACO2 and ACO3 samples showed no difference (P> 0.05) during the storage period. The values of b * were higher (P <0.001) with alginate coatings and addition of oatmeal. The weight loss of the steaks (Table 3) increased (P <0.001) during the storage period, but in the alginate coating and oat flour addition steaks were less pronounced (P <0.01). On the first day of storage, the alginate coating and the addition of oats reduced (P <0.03) the loss of mass in comparison to the treatments CON and AC. The coated fillets maintained their firmness during storage, while the uncovered fillets were softer (P <0.01). The pH did not change during the storage period (P> 0.05). Already in the second study, when analyzing the proposed new packages, we obtained that analysis of thickness demonstrated an efficacy of the formation of film around the paper. The packaging did not show improvement in the mechanical properties, as well as the permeability to water vapor; however, the color of the paper changed (P <0.002). All the hamburgers had an increase in malonaldehyde (P <0.003) and a decrease in antioxidant activity (P <0.001) during the exposure, being less intense in the samples with CEO samples and a decrease in antioxidant activity (P <0.001) during the exposure. less intense on samples with CEO samples. The samples with paper containing cinnamon essential oil presented lower shear force (P <0.001). CONCLUSION. The edible alginate coatings with oatmeal reduced lipid oxidation, maintained texture and decreased weight loss in tilapia fillets during storage. Thus, the use of fibers as reinforcement has proved to be an effective and promising technique for packaging improvement, since the results indicated that the alginate coating plus oat flour can act positively on the quality of the fillets, guaranteeing their desirable characteristics. The coating of both alginate and alginate with cinnamon essential oil did not contribute to improving the mechanical properties and permeability to water vapor of the papers. However, papers coated with alginate and alginate with cinnamon essential oil had an effect on the properties of the meat, contributing to oxidation inhibition / deceleration (due to antioxidant activity), improving and maintaining the 11 quality of the burgers during storage. Coated papers were effective in controlling lipid oxidation, in addition to helping to maintain the color and texture of bovine burgers during their life. The results of this work can contribute to improvements in the chain of meat and its products, since this new packaging system can act to prevent and reduce the oxidation processes contributing to maintenance in preservation and prolonging the useful life of the product. In addition, the development of a new packaging technology contributes not only to technological development as well, for the environment since they are more sustainable and biodegradable, making it an alternative to petroleumbased plastics. Keywords: Packaging, Sustainability, Beef quality, Fibers, Cinnamon essential oil.


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