## 1 Introduction  
Beef is an important part of European consumers' diets [1, 2], and it is the third most popular type of meat after pork and poultry [3, 4, 5]. Beef is characterised by a high nutritional value and exceptional organoleptic properties. It is a valuable source of protein, exogenous amino acids, and micronutrients that are important for human health, such as selenium, zinc, phosphorus, bioavailable iron, and vitamin B\({}_{12}\). Beef also contains multiple bioactive nutrients and antioxidants, including creatine, taurine, glutathione, and conjugated linoleic acid (CLA) [4, 6, 7, 8, 9, 10, 11, 12]. It is worth noting that red meat such as beer is also a source of beta-alanine, an amino acid that supports the production of canosine in the human body and plays an important role in muscle function [13]. Research has shown that proteins of animal origins play a vital role in the development and function of the human brain, especially in elderly people and children [13]. Moreover, beef consumption promotes well-being and physical fitness in healthy individuals older than 50 [8]. Despite the health benefits of beef, its consumption in developed countries is affected by numerous factors, including price, as well as environmental (the influence of beef production on climate change and greenhouse gas emissions) and ethical concerns (animal welfare) [4, 5, 12, 14, 15, 16]. used for the production of milk and meat. Milk production is prioritised, and surplus bulls are more often slaughtered and used in meat production than cows and heifers. Bulls that are slaughtered at 24 months of age or earlier generate the highest profits [9]. Meat from bulls is most commonly sold at retail, which is why its quality attributes, including colour, tenderness, and juiciness, should be optimised. These quality attributes are largely dependent on the muscle type. Muscle function and anatomical location are particularly important in achieving meat texture acceptable to consumers [7]. _Longissimus thoracis et lumborum_ (LTL) is the largest muscle of the bovine carcass, and it fetches high prices on the market [4; 9]. The muscle belongs to the group of deep back muscles which is engaged in maintaining posture and responsible for the extension and lateral flexion of the spine [4; 21]. The quality characteristics of LTL are usually similar, which is why LTL is commonly used as a reference muscle in research. However, visible marbling can be observed in LTL cross-sections. Marbling contributes to the tenderness, juiciness, and taste of meat [4; 7; 16; 18; 22], but it could be a limiting factor that affects consumer purchasing decisions. Modern consumers have a preference for meat with minimal visible intramuscular and extra-muscular fat, which is chosen as the \"healthier\" option. Many consumers are not aware that low-fat meat products have lower flavour profiles and lower acceptability [4; 16]. The _semimembranosus_ (SM) is a muscle that can meet consumer expectations in terms of appearance and fat content. The SM is a large and thick locomotive muscle that extends from the surface of the carcass to the femur, and it is the main locomotive muscle [23; 24]. Due to its function and high loading, the SM is characterised by a darker colour [21; 25] and lower fat content [26] than LTL. In light of the above, this study was undertaken to search for technological solutions that would improve the quality of products obtained from the meat of HF bulls, with special emphasis on standardising the quality of the LTL and SM muscles. Previous research has shown that the sous vide (SV) method increases the tenderness and juiciness of beef products made from both the _longissimus lumborum_ (LL) and SM muscles [27]. The SV technique is often used in the catering sector and the food industry to obtain products with high eating quality and nutritional value [6; 17; 28; 29]. In this processing method, vacuum-packaged raw meat is cooked at low temperatures, and the cooking time is strictly controlled [30; 31; 32].