## 3 Results and Discussion
### Lipid Oxidation in Chicken Meathalls  
In all types of tested chicken meatballs, the TBARS values determined during the entire storage period were low and remained below 0.659 mg MDA/kg (Figure 1). Even at the end of the refrigerated storage period, the value of TBARS remained within 3 mg MDA/kg in each product, which--according to [PERSON] et al. [47]--indicates that the product did not undergo excessive lipid oxidative changes. The mean values of the TBARS index in chicken products with various sage preparations, i.e., SD, SEE40, SEE70, and SEO, were lower than that in the control product, regardless of storage time. Compared to the control treatment, on day one, the lipid oxidation processes were significantly slowed down (\(p<0.05\)) only in the SEE70 product, for which the value of inhibition against lipid oxidation was 72.9%. On the other hand, in SD, SEE40, and SEO products, the value of inhibition against lipid oxidation was 23.8%, 57.2%, and 57.7%, respectively. On day seven, the only significant (\(p<0.05\)) difference in the progress of lipid oxidation processes was found between the SEE70 product and the control. Larger differences in TBARS values between individual meat products assessed in this study were found on day 14. On this day, the SD product had a significantly (\(p<0.05\)) lower TBARS value (0.473 mg MDA/kg) in comparison to the control (0.659 mg MDA/kg), but a significantly (\(p<0.05\)) higher TBARS value than the SEE40, SEE70, and SEO products. On day 14, the values of inhibition against lipid oxidation in SEE40, SEE70, and SEO meatballs were 68.1%, 64.6%, and 52.8%,  
Figure 1: Changes in the TBARS value of chicken meatballs containing MSM from chickens during refrigerated storage (mean values; \(n=3\)). Control, SD, SEE40, SEE70, and SEO: The symbols identifying the chicken meatball treatments are explained in the footnotes of Table 1. \({}^{\text{a,b}}\) Mean values marked with different letters differ significantly at \(p<0.05\)—the differences refer to chicken meatball treatments on a given day of storage. \({}^{\text{A,B}}\) Mean values marked with different letters differ significantly at \(p<0.05\)—the differences refer to days of storage of a given chicken meatball treatment. respectively. The storage time had a negative influence on the oxidative stability of all chicken meatball products, as evidenced by the increase in the TBARS values (Figure 1). However, the lipid oxidation processes significantly progressed with the extension of the storage time only in the SEO product, and there were significant (\(p<0.05\)) differences between days 1 and 7 of storage. The results of this work showed that undesirable lipid oxidation processes in chicken meatballs containing MSM from chickens were retarded by all the tested sage preparations during storage (+4 \({}^{\circ}\)C, 14 days). The best antioxidant properties were shown by the 70% (\(v/v\)) sage ethanol extract; however, comparable effects were also observed for the 40% (\(v/v\)) sage ethanol extract and essential oil. The findings of this study are consistent with the observations of [PERSON] and [PERSON] [27], who assessed the effectiveness of various sage preparations (dried leaves, ethanol, and water extracts) in improving the oxidation resistance of a model product of mineced pork. In addition, data prove that sage preparations can maintain the oxidative stability of basic raw materials used in the production of RTE chicken products, including MSM from chickens. It has been shown that compared to dried shredded sage the addition of sage essential oil or extract--water or ethanol--allows better protection of MSM from chickens obtained using high-pressure techniques against oxidative lipid changes [23]. Similarly, in the case of MSM from chickens obtained using low-pressure techniques and stored in a frozen state, the progress of lipid oxidation processes was very slow after 9 months of storage in samples with the addition of sage essential oil and sage ethanol (40%, \(v/v\)) extract [31].