## 4 Discussion  
The breakdown of proteins by proteolytic enzymes is a complex process still being explored by scientists. Protein compounds found in wheat grain influence the mashing and fermentation process. They are responsible for the content of higher alcohols, the stability of the beer head and other substances that are responsible for the flavour bouquet of the beer produced. High-molecular-weight proteins contribute to the haze of the beer and affect the quality of the beer head, while lower-molecular-weight proteins and amino acids affect the flavour of the resulting beer and the efficiency of the fermentation process. In the malting process, endopeptidases degrade proteins into lower-molecular-weight polypeptides, while exopeptidases degrade products into amino acids such as lysine, \(\gamma\)-aminobutyric acid, or asparagine [10; 13; 19; 20]. During malting, protein compounds (mainly gliadin and glutenin) are modified into low-molecular-weight proteins and amino acids [21]. According to [PERSON] et al. [22] and [PERSON] [23], the optimal range for total protein content in wheat malt is 11.0-12.5% d. m., while [PERSON] and [PERSON] [24] limit the optimal value to a maximum of 12.0% d. m. The total protein content of malts obtained from winter wheat grain was between 14.1 and 15.9% d. m. [25] and 10.2-12.6% d. m. [26]. In a study by [PERSON] et al. [27], wheat malts obtained from Croatian wheat cultivars had a total protein content of 11.2-12.5% d. m., while barley malt had a total protein content of 11.5% d. m., oat malt between 9.3 and 14% d. m., and buckwheat malt 11.1% d. m. [28]. The soluble protein content of wheat malt significantly depends on the total protein value of the wheat grain to be malted and is also negatively correlated to the pH of the wheat word [26]. Malt granulation (both 1.0 mm and 0.2 mm particle size) significantly influences the soluble protein content of the word, and finer malt granulation promotes an increase in the rate at which amino acids from the malt enter the word with the help of more efficiently working proteolytic enzymes. This leads to a high content of macromolecular protein fractions, peptides, amino acids, and FAN in the word, which affect the haze and palatability of wheat beer and the stability of beer foam [24; 29; 30]. Analyzing the literature data, the soluble protein content of malts obtained from winter wheat grain was 5.06-7.46% d. m. [26] and 4.17-4.71% [31]. In a study by [PERSON] et al. [32], five-day wheat malls obtained from wheat grains of the Elixer, Rockefeller, and Gimantis cultivars had average soluble protein contents of 4.71, 5.17, and 5.85% d. m., respectively, whereas barley malt had a soluble protein content of 8.96% d. m., oat malt between 4.99 and 9.32% d. m., and buckwheat malt 4.0% d. m. [28]. The Kolbach number (Kolbach index, KI) is a parameter that provides information on the activity of proteolytic enzymes, i.e., the extent to which nitrogenous substances contained in malt during mashing enter the word. The optimal range of the Kolbach number for wheat malt is wide, ranging from 35.0 to 45.0% [26], while [PERSON] et al. [22] narrowed the optimal value to a range of 37.0 to 40.0%. The value of the Kolbach number is significantly affected by the course of the wheat growing season, as is the case with the protein content of malting wheat grain [26]. Malts with a Kolbach number of 38.0-42.0% are used for infusion mashing, and a reduced KI value (33.0-37.0%) is used for pilsner and lager beers. Wheat malls with a KI of more than 45.0% are used for \"light\" beers [33]. The Kolbach number varied according to the hardness of the endosperm (from an average of 24.24% for malt obtained from hard wheat grain to 29.80% for malt obtained from soft wheat grain) and the degree of malt granulation (malls with a granulation of 0.2 mm were characterized by a slightly lower Kolbach number, an average of 27.45% compared to the value obtained for malls with a granulation of 1.0 mm, which was 28.05%) [27].