## 1 Introduction  
Nowadays, large-scale red meat consumption by modern society has contributed to many diseases [1, 2]. However, meat supplies nutrients and plays a vital role in human life, with its high biological value protein, mineral and vitamin contents being a crucial component of a well-balanced diet [3]. Due to increased consumer awareness with respect to the eating quality and nutritional aspects of meat, qualitative research on meat is becoming more important [4]. Meat quality describes the attractiveness of meat to consumers, which includes color, tenderness, water holding capacity, marbling and flavor [5]. The most beneficial characteristic of wild boar meat, which can be used in promotion strategies, is its low intramuscular fat content. However, compared to pork, it is a darker and less tender meat [6, 7]. Pork meat and wild boar meat should become an integral part of our daily diet. However, the microbiological risk of eating game meat is higher than from eating domestic animals [8, 9]. To avoid this, two types of packaging are used nowadays, vacuum and modified atmosphere packaging (MAP) [10]. Both types aim to achieve microbiologically stable products by inhibiting and suppressing the growth of microorganisms [8]. The shelf life of products packaged using one of these methods can be a maximum 2-3 weeks under refrigerated conditions (0-2 \({}^{\circ}\)C) [9; 11; 12]. However, traders expect the products to retain an excellent quality and freshness for as long as possible, and consumer trends have moved towards a healthy lifestyle [13]. In addition, it is now necessary to take into account that the products meet the expectations of an environmentally conscious society [14]. Consumers' perceptions and evaluations of meat quality attributes such as color influence purchasing decisions, so these are very important factors too [15; 16; 17; 18]. Based on all these factors, it was necessary to develop a process that would not affect the sensory properties of the treated products, while ensuring microbiological stability. As a result, high hydrostatic pressure treatment (HHP) was developed. This technology can preserve the original, natural appearance of the products and ensure appropriate microbiological safety, therefore increasing the shelf life of processed foods [19; 20]. The effectiveness of HHP treatment depends primarily on the pressure applied. To treat meat and meat products, pressure levels of 400-600 MPa must be used. In most cases, these treatments have led to an inactivation of more than four log units for the most common vegetative pathogenic and spoilage microorganisms, resulting in improved safety and an increased shelf-life [21]. However, the application of higher pressure levels (400-600 MPa) can induce color changes in fresh red meat due to myoglobin denaturation and oxidation [22], which are more pronounced compared to white or cured meats. For instance, beef may fade to a brownish tint after HHP treatment. This brown discoloration is due to the formation of metmyoglobin, which is a consequence of the oxidation of Fe\({}^{2+}\) ions to Fe\({}^{3+}\) ions in the HEME component of myoglobin (Figure 1) [22; 23]. In addition to the oxidative modification of myoglobin, the oxidation of other proteins that can be found in meat can also take place due to the application of HHP treatment. The process can be induced directly by reactive oxygen and nitrogen species, or indirectly by many species including radicals or reactive aldehydes and ketones [22; 25]. Thus, a high complexity of pathways and a large variety of oxidation products have been described [26]. Protein oxidation involves both the carbonylation and oxidation of thiols with the formation of disulfide bridges and the formation of compounds involving irreversible bonds resulting from a protein rearrangement (polymerization, aggregation, and scission) and a modification of amino acid chains. The formation or dissociation of disulfide bridges and the formation of carbonyl groups can be described as indicators of protein oxidation.