## 3 Results
### The Effect of Herb Additives on the Quality of Homemade Tofu
#### 3.1.4 HPTLC Polyphenolic Profile of Plant-Enriched Tofu  
As the slight differences in total phenolic compounds in enriched tofu were determined colorimetrically, tofu extracts were analyzed by HPTLC to detect polyphenols derived from the used herb additives. In all samples, the main compounds were identified as most likely originating from soy, the main component of tofu. Most likely, these are isoflav, the dominant soy polyphenols, manifesting in the plate image as yellow (Rf = 0.17 and 0.58) and blue (Rf = 0.22 and 0.46) bands after derivatization. Among the main soy isoflav, daidzein and genistein are mentioned [38], which give a similar image in HPTLC separation [39]; they were the compounds determined as the major polyphenols present in soy milk by HPLC method [40]. In enriched products, compounds derived from additives were identified, mainly from phenolic acids and the group of plant pigments. Rosmarinic acid (Rf = 0.21) was identified in samples with the addition of basil and cranberry together with Herbes de Provence. This phenolic acid is a characteristic secondary metabolite of spice plants from the _Lantiaceae_ family [41]. In addition, caffeic acid (Rf = 0.40) and chlorogenic acid (Rf = 0.02) were identified in tofu with wild garlic, basil, and Herbes de Provence/cranberry. A (+)-catechin band (Rf = 0.10) is visible in all samples, which may be overlapped by a compound that is probably an isomer or derivative of chlorogenic acid. Dyes from the chlorophyll and/or carotenoid groups, visible in the form of red UV-luminescent bands at Rf = 0.53, 0.79, and 0.89, are present in tofu with the  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Sample** & **Hardness [N]** & **Cohesiveness** &
\begin{tabular}{c} **Springiness** \\ **[mm]** \\ \end{tabular} & **Gumminess [N]** & **Chewiness [N]** \\ \hline commercial & 21.29 \(\pm\) 2.66 \({}^{\text{a}}\) & 0.55 \(\pm\) 0.04 \({}^{\text{ab}}\) & 8.55 \(\pm\) 0.41 & 11.77 \(\pm\) 1.02 \({}^{\text{a}}\) & 10.11 \(\pm\) 1.35 \({}^{\text{a}}\) \\ natural & 42.46 \(\pm\) 5.85 \({}^{\text{c}}\) & 0.55 \(\pm\) 0.06 \({}^{\text{ab}}\) & 8.47 \(\pm\) 0.10 & 23.37 \(\pm\) 5.81 \({}^{\text{bc}}\) & 19.77 \(\pm\) 4.80 \({}^{\text{bc}}\) \\ with wild garlic & 24.43 \(\pm\) 2.90 \({}^{\text{ab}}\) & 0.50 \(\pm\) 0.03 \({}^{\text{ab}}\) & 8.26 \(\pm\) 0.30 & 12.05 \(\pm\) 0.58 \({}^{\text{a}}\) & 9.93 \(\pm\) 0.83 \({}^{\text{a}}\) \\ with black cumin & 47.77 \(\pm\) 1.60 \({}^{\text{c}}\) & 0.58 \(\pm\) 0.03 \({}^{\text{a}}\) & 8.54 \(\pm\) 0.17 & 27.84 \(\pm\) 2.40 \({}^{\text{c}}\) & 23.74 \(\pm\) 1.84 \({}^{\text{c}}\) \\ with basil & 31.02 \(\pm\) 1.81 \({}^{\text{b}}\) & 0.59 \(\pm\) 0.02 \({}^{\text{a}}\) & 8.40 \(\pm\) 0.08 & 18.14 \(\pm\) 0.94 \({}^{\text{ab}}\) & 15.30 \(\pm\) 0.77 \({}^{\text{ab}}\) \\ with Herbes de Provence & 24.45 \(\pm\) 0.76 \({}^{\text{ab}}\) & 0.46 \(\pm\) 0.03 \({}^{\text{b}}\) & 8.40 \(\pm\) 0.16 & 11.33 \(\pm\) 0.37 \({}^{\text{a}}\) & 9.50 \(\pm\) 0.17 \({}^{\text{a}}\) \\ and cranberries & & & & & \\ \hline \hline \end{tabular} a–c—means marked with different letters are statistically different (\(p<0.05\)) within the column.  
\end{table}
Table 3: Selected parameters determining the texture of fresh tofu samples.  
addition of green herbs. Based on the pattern of bands in the chromatograms, it can be concluded that the highest degree of enrichment in polyphenolic compounds occurs when adding basil (Figure 4, Track 5). To our knowledge, the HPTLC technique was used for the first time to confirm the enrichment of tofu with polyphenols from plant additives.