## 3 Results and Discussion
### Amino Acids  
The literature on the subject includes very few studies that focus on the specific amino acid content of cabbage [30,31], and, to date, no studies have focused on the form of sulfur used for fertilization and the impact of storage on parameters related to amino acids. According to [32], increasing the S content of soil reduced the cysteine and methionine content in kohlrabi by 16-28%, while the valine, tyrosine, aspartic acid, and serine values remained constant. With increasing soil S content, the levels of threonine, isoleucine, leucine, arginine, alanine, and the sum of essential amino acids decreased from 37% to 9%. The histidine concentration increased with increasing S fertilization. Table 3 summarizes the results of content analysis for 16 of the amino acids commonly found in proteins. The protein content (i.e., the sum of individual amino acids) was 10.463-21.755 mg\(\cdot\)g\({}^{-1}\) FM. Glutamine was the major amino acid detected in the leaves of white-head cabbage Stonehead cv., followed by tyrosine, alanine, proline, serine, lysine, leucine, valine, and threonine. The results indicate that, with increasing soil S content, the sulfur amino acid methionine content decreased. These results correspond with the findings of [PERSON] et al. [33] and [PERSON] et al. [32]. In our study, the second sulfur amino acid, cysteine, was not detected. Regardless of treatment, fresh cabbage had similar amino acid content, ranging from 10.463 to 10.92 mg\(\cdot\)g\({}^{-1}\) FM, which suggests that fertilization had very little impact on amino acid levels in the research material. Following storage, the amino acid content  
\begin{table}
\begin{tabular}{l c c c c c c c c c} \hline \hline  & **1** & **2** & **3** & **4** & **S1** & **S2** & **S3** & **S4** \\ \hline \multicolumn{10}{c}{mg\(\cdot\)g\({}^{-1}\) FM} \\ \hline Asp & 1.068 \(\pm\) 0.114  & 1.065 \(\pm\) 0.009  & 1.169 \(\pm\) 0.019  & 1.148 \(\pm\) 0.098  & 1.201 \(\pm\) 0.017  & 1.359 \(\pm\) 0.008  & 1.544 \(\pm\) 0.011  & 2.526 \(\pm\) 0.013  \\ Thr & 0.359 \(\pm\) 0.001  & 0.348 \(\pm\) 0.001  & 0.364 \(\pm\) 0.001  & 0.342 \(\pm\) 0.001  & 0.354 \(\pm\) 0.001  & 0.426 \(\pm\) 0.002  & 0.403 \(\pm\) 0.001  & 0.696 \(\pm\) 0.002  \\ Ser & 0.470 \(\pm\) 0.002  & 0.479 \(\pm\) 0.002  & 0.451 \(\pm\) 0.002  & 0.454 \(\pm\) 0.002  & 0.585 \(\pm\) 0.003  & 0.469 \(\pm\) 0.002  & 0.455 \(\pm\) 0.002  & 0.986 \(\pm\) 0.043  \\ Glu & 2.975 \(\pm\) 0.112  & 3.388 \(\pm\) 0.214  & 0.279 \(\pm\) 0.124  & 0.3052 \(\pm\) 0.196  & 4.412 \(\pm\) 0.254  & 3.873 \(\pm\) 0.157  & 4.713 \(\pm\) 0.321  & 7.490 \(\pm\) 0.528  \\ Pro & 0.516 \(\pm\) 0.004  & 0.669 \(\pm\) 0.002  & 0.515 \(\pm\) 0.013  & 0.561 \(\pm\) 0.003  & 0.617 \(\pm\) 0.003  & 0.606 \(\pm\) 0.017  & 0.590 \(\pm\) 0.002  & 0.848 \(\pm\) 0.006  \\ Gly & 0.322 \(\pm\) 0.002  & 0.290 \(\pm\) 0.001  & 0.290 \(\pm\) 0.001  & 0.336 \(\pm\) 0.011  & 0.310 \(\pm\) 0.002  & 0.301 \(\pm\) 0.001  & 0.320 \(\pm\) 0.002  & 0.350 \(\pm\) 0.003  & 0.611 \(\pm\) 0.005  & 0.611 \(\pm\) 0.005  \\ Ala & 0.639 \(\pm\) 0.005  & 0.497 \(\pm\) 0.003  & 0.585 \(\pm\) 0.014  & 0.605 \(\pm\) 0.014  & 0.523 \(\pm\) 0.002  & 0.608 \(\pm\) 0.004  & 0.691 \(\pm\) 0.005  & 0.801 \(\pm\) 0.007  \\ Cys & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 \\ Val & 0.395 \(\pm\) 0.001  & 0.37 increased noticeably for each of the experimental scenarios, from 12.338 to as much as 21.755 mg\(\cdot\)g\({}^{-1}\) FM. In cabbage grown using potassium sulfate, this increase was twofold. The 'Stonehead' cultivar of white cabbage was characterized by the highest amino acid content being that of glutamine, and a very low methionine content. Such a relation was also noted by [PERSON] et al. [20], who determined the levels of 12 amino acids in green cabbage and 8 in red cabbage. The study by [PERSON] et al. [31] demonstrated that sulfur fertilization resulted in an increase in free amino acid content following storage, which was confirmed by the results of this study.