## 1 Introduction  
Population growth over the last century has led to a significant increase in food demand. The United Nations projects the world population to reach 9.7 billion by 2050, 10.8 billion by 2080 and 11.2 billion by 2100 [1]. Some estimates suggest that food production efficiency will need to increase by 50-70% by 2050 to feed an additional two billion people [2]. Accordingly, sustainable development has become a key consideration for the food industry and encourages the exploration of processing techniques that can improve the nutritional and functional properties of food while minimizing environmental impact [3]. Thus, processing by-products such as blood not only solves the issue of waste management but also provides significant benefits in terms of environmental sustainability and nutritional value, which can contribute to the circular economy [4]. Blood is considered one of the main by-products of the meat industry due to the large amount produced daily [5]. Blood has an outstanding nutritional value due to its high protein content and amino acid profile. For this reason, it is also called \"liquid protein\" or \"liquid meat\" [6]. Blood constitutes approximately 2.4-8% of the animal's live weight or 6-7% of the lean meat content of a slaughtered animal [7]. This red-colored liquid connective tissue can be considered a complex fluid composed of water, cells, enzymes, proteins and other organic and inorganic substances, which can be divided into two fractions, the cellular fraction and the plasma [8]. Animal blood plasma (serum) is considered the most complex colloidal system of all known natural fluids. Since plasma contains complexes of many different biologically active compounds, it is reasonable to consider blood a \"super complex colloidal system\". Plasma is the liquid part of blood that does not contain blood cells [9]. Mammalian plasma usually contains 6-8% \(w/v\) protein, mainly albumin (56-60%); globulins -\(\alpha_{1}\)-, \(\alpha_{2}\)-, \(\beta\)- and \(\gamma\)-globulins (36-40%) and fibrinogen (0.6-4%) [10]. Blood is currently underutilized, and its main applications are focused on animal feed, composting or biogas production, which represent low added value [11]. In food applications, blood plasma plays an important role in the meat industry, as it forms a gel when heated and has better binding properties than many other binders (e.g., gelatin, meat powders and wheat gluten), although it is weaker than egg white. It also has excellent emulsifying properties, which help to bind meat proteins, fats and water in products such as sausages and pates. The food industry also uses it as a protein supplement and fat substitute, as well as an egg substitute in bakery products, thereby reducing production costs. Blood plasma can also be used to increase the protein content of pasta products, which could be a cost-effective solution for manufacturers [8; 12]. The processing of blood for human consumption or higher added value uses (e.g., biomaterials, bioactive compounds) still represents a small part of total blood consumption. A total of 30-40% of total food production is lost as waste and/or by-products before reaching the market [5]. Rapid advances in science and technology may transform blood collected from slaughterhouses into a useful alternative source for human consumption, as blood has unique nutritional and functional properties. This practice is an excellent effort to minimize environmental impacts and encourage innovation to improve resource sustainability [13; 14]. The meat industry is faced with the challenge of making better use of all slaughter products, including blood. Finding new applications for blood components is an important challenge for scientists and there is a need to develop processes and applications that allow for the larger-scale utilization of animal blood, both to eliminate the significant risk of contamination and to prevent the loss of this potentially valuable material [14; 15].