# Some Plant Food Products Present on the Polish Market Are a Source of Vitamin B12
## 3 Results and Discussion  
The range of linearity of the calibration curve with a correlation coefficient R\({}^{2}\) = 0.999 for vitamin B12 is shown in Figure 1.  
Table 1 presents the content of cyanocobalamin (vitamin B12) in the studied solid samples. In the sea-buckthorn jam sample, a significant amount of cyanocobalamin was detected, up to 224.5 \(\upmu\)g\(\cdot\)kg\({}^{-1}\) (Figure 2). Figure 1: Calibration curve of cyanocobalamin. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Product** & **Manufacturer** &
\begin{tabular}{c} **Content of Vitamin B12** \\ **(\(\mathbf{\mu g}\)-\(\mathbf{kg^{-1}}\)) (\(\mathbf{\hat{x}}\) \(\pm\) SD)** \\ \end{tabular} \\ \hline Sea-buckthorn jam 100\% & Lowicz & 224.5 \(\pm\) 0.5 \\ Sauerkraut & Matyjaszczyk & Traces \\ Sauerkraut & Brassica & Traces \\ Sauerkraut & Dominik & Traces \\ Sauerkraut & Stefanek & Traces \\ Sauerkraut & Farma Swietokrzyska & Traces \\ Pickled cucumber & Matyjaszczyk & Traces \\ Pickled cucumber & Kuchnia Polska & Traces \\ Pickled cucumber & Stefanek & Traces \\ Pickled cucumber & Farma Swietokrzyska & Traces \\ Pickled cucumber & Raj & Traces \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Content of cyanocobalamin in solid samples of fermented vegetable products. Figure 2: HPLC chromatogram obtained after the analysis of the sea-buckthorn jam sample. In solid samples of sauerkraut of all manufacturers, only trace amounts of vitamin B12 were detected. The same results were obtained by the analysis of cucumber solid samples. In the next stage of the study, liquid samples of pickled cucumber and beetroot brines, as well as sauerkraut and parsley juices, were analyzed. Only the latter samples were found to contain significant amounts of vitamin B12, up to 50.5 \(\upmu\)g.L\({}^{-1}\), while other samples were found to contain only trace amounts of vitamin B12 (Table 2, Figure 3). In other sauerkraut juices and fermented cucumber juices, only trace amounts of vitamin B12 were detected. Additionally, in samples of white borscht from three different manufacturers, only traces of vitamin B12 were detected. This study used HPLC analysis to determine the content of cyanocobalamin in selected fermented plant products and sea-buckthorn jam available on the Polish market. The main intention of this study was to find a healthy, natural and easily available source of vitamin B12 for people at risk of deficiency, in particular vegetarians and vegans. The scientific community is still looking for new and better vegetable sources of cobalamin. [PERSON] [8] demonstrated that spinach grown with organic fertilizers (addition of cow dung at the rate of 10 g\(\cdot\)kg\({}^{-1}\)) increased the B12 content in spinach leaves by close to two-fold (from 6.9 to 17.8 ng\(\cdot\)g\({}^{-1}\) dry weight). Some studies report that some mushrooms and nori seaweed contain trace amounts of vitamin B12 [9; 10]. Vitamin B12 was also found in dried shitake mushrooms (Lentinual edodes) with a content of approximately 56.1 ug\(\cdot\)kg\({}^{-1}\) of dry matter. Unfortunately, by a typical portion of spinach, mushrooms or nori, a consumer is not able to cover the daily requirement for cobalamin, and daily consumption of shitake mushrooms at 50 g per day would even not be possible [1]. For many years, edible bamboo shoots were thought to contain significant amounts of vitamin B12, which ultimately proved to be a misconception [12]. Only trace amounts were found in broccoli, asparagus, Japanese butterbur and Mung Bean sprouts [10]. Still, other studies have found that edible species of black trumpet and golden chanterelle contain vitamin B12 at a 10.9-26.5 ug\(\cdot\)kg\({}^{-1}\) level of dry weight [13]. A good source of vitamin B12 may be the Mankai, Aphanizomenon and Nostocidible species of cyanobacteria, which are usually available as supplements [11; 26].