## 1 Introduction
Therefore, studies aimed at changing the type of fat and meat that are used in traditional meat products and include in-depth research on the physicochemical, mechanical and organoleptic parameters of these products represent an efficient approach that also has a health effect. It is very important, when differentiations are made in the production of traditional meat products, to evaluate the impact on many factors such as physicochemical, textural or sensory attributes. Also, the formulated products should not deviate much from the original ones to maximize consumer acceptability [20]. As mentioned above, the most famous strategies when attempting to modify traditional meat products like sausages to improve their characteristics are, among others, the reduction or total substitution of fat content or alteration of the lipid profile, which is very important for the specific meat products because of their high fat content, which exceeds 30% in most cases [21; 22; 23]. Another very promising methodology is the formulating of the classic recipes of traditional meat products like sausages, with the use of alternative raw materials from other origins in different ratios, to improve their textural, physicochemical, sensory and maybe nutritional characteristics. Considerable research has been conducted in this field, and for example, [PERSON] et al. (2007) [24] and [PERSON] et al. (2011) [25] investigated the use of duck meat in sausages, which presented high nutritional value, on their textural and sensory characteristics. Another example is the modification of fat origin, which traditionally originates from pork backfat, and more specifically [PERSON] et al. (2020) [26] investigated the use of chicken skin as a fat source in sausages and evaluated its impact on various quality properties, including sensory attributes. A challenge which many researchers faced when they tried to modify the traditional meat products by altering the meat or fat origin was the correlation of physicochemical, objective textural and sensory attributes and measurements. The difficulty grew significantly considering that in order to establish a robust and clear opinion about the efficiency of a new product, one should include many levels or points of analysis [27; 28]. Thus, a suitable experimental design is crucial for this target, and the use of mixture design (extreme vertices design) enables the development of mathematical modeling, which gives the response prediction and the best desirable performance at the same time [29]. Also, presenting data for combining sensory with physicochemical and textural properties can be challenging; thus, the use of sophisticated statistical experimentation becomes necessary [30]. The aim of the present study is to evaluate for the first time the use of buffalo meat and fat as alternative raw materials for the production of traditional Greek sausages and their impact on physicochemical, textural and sensory characteristics and investigate the efficiency of a mixture design combined with a balanced incomplete block design (BIBD) and multivariate techniques (cluster and principal component analysis) to combine the different origin of variables and evaluate the best combinations of the raw materials.