# Influence of Tomato Pomace on the Quality of Canned Pork Meat with Reduced Nitrogen Compounds
## 4 Discussion
In the current study, samples containing the highest concentration of tomato pomace showed the highest antioxidant properties. These observations were also confirmed by other authors [44], who studied the effect of grape pomace addition in the production of meat products with reduced nitrite content. Similar results were obtained by other researchers [34] on the antioxidant properties of fermented sausages with the addition of tomato by-products. A similar trend was also observed by [PERSON] et al. [45] in the experiments on the effect of powdered passion fruit extract on the antioxidant activity of preserved meat products. Based on the current study, it can be concluded that tomato peels and seeds powder can be used as a valuable natural preservative in processed meat. Despite these promising findings, it is important to consider the role of traditional antioxidants widely used in the meat industry, such as ascorbic acid and rosemary extract. Although tomato peels and seeds exhibit promising antioxidant properties, their effectiveness as standalone antioxidants may be somewhat lower compared to traditionally used additives. Nevertheless, due to their natural origin, potential health benefits, and the possibility of being used as secondary raw materials, they represent an attractive alternative or complement to conventional preservatives. Therefore, it appears justified to conduct further comparative studies aimed at a comprehensive evaluation of the effectiveness of tomato-derived components in relation to conventional antioxidants used in the meat industry [18]. Lipid oxidation can be considered one of the main causes of meat product quality degradation. This phenomenon can lead to the formation of many products that contribute to the deterioration of the smell and taste of meat products [40]. Tomato peels and seeds provide many valuable bioactive compounds with antioxidant properties. The most representative antioxidant compounds found in both tomato peel and seeds include carotenoids, polyphenols and phytosterols [33]. The dominant flavonoids are rutin, naringenin and their derivatives, and quercetin [46]. Additionally, tomato pomace, especially tomato seeds, contains large amounts of vitamin C. Recently, polyphenols and secondary plant metabolites, such as flavonoids, have attracted much attention due to their use in the food industry [47]. Bioactive compounds present in plant raw materials used as natural additives in meat products caused an antioxidant effect and inhibited oxidation, thus reducing the TBARS values of meat products [38; 48; 49; 50]. However, the results obtained in the current study were not consistent with the observations of other authors. In the presented studies, the addition of tomato peels and seeds powder accelerated the oxidation reaction of fats in meat products. Compared to other samples, the control sample had a significantly (P < 0.05) lower MDA content. The reason for this is likely that the flavonoids and vitamin C present in TPSP are sensitive to environmental conditions (temperature, light, oxygen and pH) [47]. Therefore, the heating processes and high temperatures applied to the experimental cannot meat may have altered the structure of flavonoids. As a result, this change could have shifted their role from acting as antioxidants to exhibiting pro-oxidant activity. Pro-oxidant activity is usually catalyzed by metals, especially transition metals such as Fe and Cu [51]. Moreover, during thermal processing, polyphenols degrade according to the first-order kinetics, leading to the formation of degradation products such as quinones and phenoxy radicals, which can increase the generation of reactive oxygen species (ROS) and enhance prooxidant activity [52; 53]. Studies on fruit extracts subjected to sterilization (110-130 \({}^{\circ}\)C) showed a decrease in the total content of polyphenols by 30-60% with the course of the first-order kinetics, which indicates a significant loss of their original antioxidant properties [54].