Extratos vegetais encapsulados no controle da oxidação lipídica de hambúrguer ovino

Abstract

The application of natural antioxidants from encapsulated plant extracts in meat products, aiming to reduce oxidative reactions, has been more explored lately. Based on this trend, this study aimed to encapsulate extracts of olive leaves and red araçá using gelatin and/or tragacanth gum, by complex coacervation or lyophilization, and apply in sheep meat hamburger, in order to reduce oxidative degradation in these products. The work was divided into two studies. In the first study, the phenolic extract obtained from olive leaves was encapsulated by complex coacervation or lyophilization using gelatin and/or tragacanth gum. Initially, the ideal pH was determined for the occurrence of complex coacervation, and after encapsulation, the particles were characterized, and later applied to hamburgers with sheep meat, which were stored for four months under freezing. These products were evaluated for peroxide content, thiobarbituric acid reactive substances and the release of phenolic compounds in vitro. It was observed that at pH 4 the maximum interaction between the wall materials occurred. The particles produced with gelatin and gelatin/tragacanth showed superior values of encapsulation efficiency and antioxidant activity in relation to particles with only tragacanth. Regardless of the wall material used, the particles produced had an irregular shape. The particles with gelatin and gelatin/tragacanth showed greater protection potential in sheep meat burgers against oxidative degradation in relation to particles with only tragacanth. These particles were more efficient than the use of sodium erythorbate as antioxidants in hamburgers, but vitamin C was the treatment that showed the best results. Thus, the particles produced with gelatin or gelatin/tragacanth are presented as natural ingredients that can replace artificial antioxidants in the elaboration of sheep burger. The second study was carried out using the encapsulation of red araçá extract in different concentrations of tragacanth gum, by lyophilization. The particles were characterized and later added to sheep meat hamburgers, which were stored for twelve days under refrigeration. It was observed that the higher the concentration of wall material used, the higher the encapsulation efficiency and lower values of antioxidant activity. It was possible to encapsulate the extract rich in phenolic compounds of red araçá with all concentrations of gum tragacanth tested, with the particles having an irregular shape. Artificial antioxidants and red araçá extract were more efficient against lipid peroxidation in hamburgers, compared to those containing particles with phenolic extract. Thus, the encapsulation of red araçá extract with tragacanth gum by lyophilization was not very efficient for the protection of sheep meat hamburger from oxidative degradation. However, these particles showed higher antioxidant activity than the control sample, without additives during the first 6 days of storage. Considering that sheep meat has a high content of mono- and poly-unsaturated fatty acids, further investigation of the application of natural antioxidants is necessary.