In recent years, there has been a rapid development of a new branch of food engineering, referred to as the food matrix engineering (spatial architecture) of materials [4; 5]. In comparison to vacuum impregnation, it was demonstrated that freezing/thawing and compression caused more changes in the internal microstructure of apple tissue, resulting in the formation of cell cavities [6]. Regardless of the changes in the microstructure caused by vacuum impregnation, the integrity of the plant tissue cells is unaffected [7; 8]. Vacuum impregnation can be carried out in many ways:  
* Dry vacuum impregnation (DVI), in which the contact of the liquid and the impregnated material takes place in the reduced pressure phase;
* Wet vacuum impregnation (WVI), in which the contact of the liquid and the impregnated material takes place before the reduced pressure phase, under atmospheric pressure [9]. In the course of vacuum impregnation, two groups of related phenomena can be distinguished:  
* Deformation relaxation phenomena, DRPs;
* Hydrodynamic mechanism, HDM [10; 11; 12]. Many different factors influence the impregnation process. Most often, they are divided into two groups: the external and internal factors [13]. In the group of external factors, the most important is the impregnation pressure (p\({}_{1}\)). It is the driving force behind the entire process. Most often, in the impregnation of biological materials, pressures ranging from 50 to 600 hPa are used [12; 13; 14; 15; 16; 17; 18; 19]. The t\({}_{1}\) and t\({}_{2}\) times are identified in the literature as important factors. The longer the time, the lower the pressure is maintained and the lesser the weight loss, which results in a greater degree of impregnation [20]. In the scientific literature on impregnation, the ranges of the t\({}_{1}\) and t\({}_{2}\) time variations, assumed by the researchers, are quite extensive. Some apply pressure in the range from 0 to 10 min, others conduct research in the range from 10 to 120 min [17; 18; 21; 22]. The viscosity index, temperature and concentration of the impregnating liquid also affect the effectiveness of the impregnation [2; 13; 17; 22]. Among the internal factors, the properties of the impregnated material and its structure should be mentioned. Porous materials with numerous voids in their tissues, such as fruit and vegetables, are particularly susceptible to impregnation. They show a higher degree of porosity compared to meat, fish and cheese [10; 14; 15; 23]. There are many studies on the use of vacuum impregnation in food production [12; 13; 14; 15; 17; 18; 19] and there are many reports on the beneficial effect of vacuum impregnation on the structure of tissues. The use of this treatment reduces the probability of thermal damage to the organic tissue and also prevents the loss of the aroma and color of fruit and vegetables [24]. This is only possible by removing oxygen from the pores, without the need for antioxidants. Other researchers present the possibility of introducing antioxidants or antimicrobial agents into the structure of the material, which can extend shelf life [3]. The results of studies on the application of impregnation as a pretreatment before freezing are available [25]. Impregnation is often used as a pretreatment that precedes heat treatment [26; 27]. There is a scarcity of scientific data on the vacuum impregnation of cereal grains in the scientific literature [28]. Barley is subjected to steeping. In this phase, the barley reaches a moisture content of 42 to 44% [29]. Steeped barley is then directed to the malting department called the sprouting room. In modern malting houses, sprouting boxes or drums are used for sprouting barley, in which the process is completely mechanical. The barley sprouting cycle lasts 5-8 days at a temperature of 12-20 \({}^{\circ}\)C. The duration of the process depends on the variety of barley, the method of malting and the sort of malt [29; 30].