## 3 Results and Discussion
Cooking loss in hamburger patties was not influenced by the incorporation of lemon balm powder at 1% [37]. The color attributes of meat and meat products play an important role in the purchasing decisions of consumers [47]. Bright red is generally considered as a color strongly related with high quality and freshness, while discolored, pale or darker meat is characterized as low quality due to poor preservation [48]. A bright red color in meat is observed as a result of the conversion of deoxymyoglobin into oxymyoglobin. However, the constant exposure of the meat surface to oxygen causes enhanced oxidation rates and the generation of free radicals that contribute to the transformation of myoglobin into metmyoglobin, perceivable due to its characteristic brown pigment [49]. Instrumental meat color assessment is essential, since objective measurements are achieved [50]. Figure 2: Effect of polyphenols and/or herbal mix on the (**A**) pH, (**B**) cooking loss (%) and (**C**) shear force (N) values of pork sausages on month 0, 1, 2 and 3 after refrigerated storage. The treatment groups were as follows: control (CON), with the addition of sodium nitrite (SN), polyphenols (POL), herbal mix (NM) and polyphenols and herbal mix (POL + NM). \({}^{\text{a,b}}\) Values with different letters within a parameter in a specific storage period are significantly different (\(p<0.05\)). \({}^{\text{A-C}}\) Values with different letters within the same group among different storage periods are significantly different (\(p<0.05\)). The L value was not different among the experimental groups during the entire experimental period (Table 1). In contrast, [PERSON] et al. [46] reported a decrease in the L value as a result of adding green tea and olive leaves' extract (500 mg/kg) to frankfurter-type sausages. No effect on the lightness of pork sausages after the addition of roscenary and green tea extracts at the levels of 1500-2500 and 100-300 pm, respectively, was observed in another study [51]. On the other hand, redness (a*) was steadily higher in the SN group compared to the other groups during the sampling days (\(p<0.05\); Table 1). The chroma (C*) value was also greatest in the SN group compared to the other groups; intermediate values were recorded in the NM and NM + POL groups and the lowest values in the CON and POL groups (\(p<0.01\); Table 1). A different trend was observed for hue angle (H*); the highest in the NM and NM + POL groups, intermediate in the CON and POL groups and the lowest in the SN group (\(p<0.01\), Table 1). Nitrites and nitrates provide the intense red color of meat products particularly appreciated by consumers [52]. As already shown, the addition of olive leaf extract (40% oleuropein) as a replacement for nitrite/nitrate decreased the intensity of the red color in ripened pork sausages [53], possibly due to a lack of nitroso-myoglobin formation or a browning reaction during storage [54]. Moreover, bologna sausage [55] and cold-smoked sausages [56] enriched with natural antioxidants also showed a lower a* index compared to samples containing sodium nitrite. Furthermore, the values for yellowness (b*) were significantly greater in the NM and POL + NM groups compared to those observed in the other groups (\(p<0.05\); Table 1). It is well-known that turmeric is an important natural source of yellow pigment [57]. The intensity of the yellow color was also increased in lamb sausages enriched with turmeric extract at 250-750 mg/kg [24]. Ameliorated oxidative stability in pork sausages was shown due to the addition of natural polyphenols and/or an herbal mix, since the levels of MDA were decreased in the treated groups compared to controls at month 1, 2 and 3 (\(p<0.05\); Table 2). This fact could be ascribed to the antioxidant activities of the added olive polyphenols and/or herbs that protect sausages against the deteriorating effects of peroxidation. In food systems, polyphenols bind to proteins and alter their functionality and structure.