## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sample Produced** & **Barley Malt** & **Barley Malt** & **Barley Malt** & **Wheat Malt** \\
**after** & **Zlatko** & **Oswit** & **Tristan** & **Lorena** \\
**(CU/g)** & **(CU/g)** & **(CU/g)** & **(CU/g)** & **(CU/g)** \\ \hline Steeping & 2.5 \(\pm\) 0.26 & 1.8 \(\pm\) 0.20 & 2.7 \(\pm\) 0.23 & 0.6 \(\pm\) 0.26 \\
1 st day of germination & 73.8 \(\pm\) 0.38 & 38.7 \(\pm\) 3.77 & 61.5 \(\pm\) 3.33 & 28.4 \(\pm\) 1.61 \\
2 nd day of germination & 99.2 \(\pm\) 1.32 & 69.6 \(\pm\) 1.80 & 110.0 \(\pm\) 0.28 & 45.5 \(\pm\) 0.93 \\
3 rd day of germination & 127.9 \(\pm\) 1.48 & 83.7 \(\pm\) 0.42 & 131.2 \(\pm\) 5.69 & 59.0 \(\pm\) 2.10 \\
4 th day of germination & 131.4 \(\pm\) 0.81 & 92.5 \(\pm\) 2.19 & 147.9 \(\pm\) 3.29 & 65.8 \(\pm\) 1.43 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The \(\alpha\)-amylase activity of malt flour samples determined by the Ceralpha method. Figure 1: Influence of the addition of different amounts of malt flour on the Falling Number and Liquefaction Number (lines indicate a linear trend). range. The intercept was set at 20 s\({}^{-1}\), which corresponds to the FN value of 350 s obtained for standard wheat starch without \(\alpha\)-amylase activity. Similar to the results obtained by using malt flour, the use of the different amounts of malt extract (5% \(w/v\)) also resulted in a nonlinear relationship between FN and \(\alpha\)-amylase activity (Figure 2). FN decreased below 200 s when more than 3 mL of malt flour was used for samples with \(\alpha\)-amylase activity higher than 40 CU/g. As with the use of large amounts of malt flour, this also means that the detection range is significantly reduced when using large aliquots of malt extract (>3 mL). To determine the agreement between the standard Ceralpha method and the modified FN methods, a Bland-Altman analysis was performed. The results are shown in Tables 3 and 4. The results presented in Table 3 refer to the use of LN to estimate \(\alpha\)-amylase activity in the malt samples. The standard method and the modified methods were highly correlated for all quantities of malt flour and extracts analyzed, as the correlation coefficients were greater than 0.900. However, it should be noted that the correlation coefficient decreased as the amounts of malt flour and malt extract increased. The highest correlation was found between the standard method and the modified method when 0.1 g of malt flour was used (\(r\) = 0.984), and between the standard method and the modified method when 2 mL of malt extract was used (\(r\) = 0.977). However, the presence of a high correlation between two methods does not necessarily indicate a good agreement between the results obtained by these methods. In other words, a high correlation does not necessarily mean that the results are in close agreement. It is important to consider this fact because it indicates that a strong relationship between two methods does not necessarily imply accurate results. This may be the case when the differences between the results are consistent, implying that the error is systematic rather than random. In such cases, the correlation remains high even if the results do not agree with each other [27; 28]. In view of this, the Bland-Altman analysis was also used to investigate the agreement between the methods. Figure 2: Influence of the addition of different amounts of malt extract on the Falling Number and Liquefaction Number (lines indicate a linear trend). The bias moved from positive to negative values with increasing amounts of added malt flour and malt extract. A tendency to underestimate \(\alpha\)-amylase activity was observed at higher \(\alpha\)-amylase levels. This phenomenon can be attributed to the reverse flow effect that occurs when the stirrer approaches the bottom of the test tube. This effect is more pronounced in low viscosity paste due to a higher upward flow velocity.