## Results and Discussion
### Proximate Composition and Physicochemical Parameters
The cooking loss (CL) did not show significant differences between control and treatments with chemical and natural antioxidant (\(p\geq 0.05\)). Although this, the reformulated sausages presented higher CL (4.94% and 4.81% for T1 and T2, respectively), than control (2.35%). The CL of the frankfurters depends on the cooking temperature, cooking time, the ingredients, and fat amount in the products [6]. In the present study, the formulations were very similar (only 0.53% of murta or chemical antioxidant was added), and the processing parameters (temperatures, times, etc.) were the same for all treatments, which could explain the lack of significant differences between control and reformulated samples. Other authors reported differences in cooking loss frankfurters with reduced-fat [6; 41] and with fiber incorporation [47], but in these cases, the proportion and/or the type of ingredients reformulation were changed between treatments. Color plays an important role in the consumer perception and preferences in modified meat products [10; 11], like frankfurters. In this research, the instrumental analysis showed that the color properties (a*, b* and L*) of the frankfurters were affected by the reformulation (Table 4). Similar findings were observed previously by other authors, who reported a significant influence of the plant extract addition on frankfurters color [1]. The highest a* value was observed in frankfurters formulated with chemical antioxidant (Plus Color), while samples from control and murta treatments presented lower values (\(p\leq 0.05\)). The highest b* value was found in control samples and frankfurters with the addition of chemical antioxidant Plus Color, being these frankfurters more yellowness (\(p\leq 0.05\)), compared to frankfurters with murta added. Finally, in contrast to redness, the lowest lightness (L)* value was observed in the samples from T1 treatment (51.33), while the control frankfurters had the highest values (53.65) and murta samples presented intermediate values (52.27 \(\pm\) 1.44). It was expected that frankfurter formulated with murta presented the highest value in redness, due to the characteristic red color of this fruit. However, the frankfurters formulated with murta exhibited the lowest redness (a*) values, without significant differences between control and murta treatments (\(p\geq 0.05\)). These findings could also be related to the low content of murta powder added in the sausage formulation. Similarly, sausages from murta treatment show the lowest b* value, in comparison with control and synthetic antioxidant treatment. The decrease in b* values attests to greater clarity in terms of cleanness or clearness [48]. Another possible explanation for the differences in frankfurter color can be the changes in murta pigments, which can suffer degradation due to high temperatures during frankfurters manufacturing. The levels of anthocyanins can explain the different intensity in the fruit color, especially for murta, which is red-rose, in comparison with other Chilean berries [49]. Regarding L* values, [PERSON] et al. [2] reported that this parameter in meat products are related to fat and moisture content (mainly due to the water and fat in the surface of these products affects light reflection) because fat and moisture make the product lighter colored. In our case, the lightness was related to the moisture content. The control (T0) treatment, with the lowest fat and highest moisture contents, showed the highest L* values than the samples from treatments T1 and T2. In the frankfurter formulation, when reducing the fat content (by using fat replacers), the values of L* and b* decreased and a* value increased, but when changed the fat level and meat content (myoglobin), several variations can be found in color [50; 51]. However, [PERSON] et al. [52] indicated that the incorporation of non-meat ingredients often mitigates differences in color of meat products.