# Physicochemical and Molecular Properties of Spelt and Wheat Starches Illuminated with UV Light
## 3 Results and Discussion  
### Molecular Weight Distribution  
The HPSEC-MALLS-RI method allowed us to determine the molecular weights of the polysaccharides included in the amylopectin fraction. Based on the shape of the chromatograms, they were divided into two regions corresponding to the amylopectin and amylose eluted fractions. Values of M\({}_{\mathrm{w}}\) and R\({}_{\mathrm{g}}\) taken from the analyzed chromatograms for cereal starches irradiated with UV radiation are presented in Table 1.  
Native spelt and wheat starches contain the polysaccharide chains with M\({}_{\mathrm{w}}\) of the order of 8.2 \(\times\) 10\({}^{6}\) g/mol and 23 \(\times\) 10\({}^{6}\) g/mol, respectively, as presented in our earlier publication [16]. For spelt starch, five hours of exposure to UV radiation caused a decrease in the molecular weight values, which indicates the degradation of the polysaccharide chains in the granule. On the other hand, prolonged irradiation leads to an increase in the molecular weight of the polysaccharide chains. The observed increase indicates the possibility of interactions between macroradicals and radicals from the polysaccharide chains formed during the breakdown of glycosidic bonds between glucose molecules. For the polysaccharide chains, longer UV exposure leads to further transformations that significantly reduce the weight-average molecular weight of the polysaccharides. Irradiation for 50 h resulted in the chains with the highest molecular weights. This may result from the recombination of the intermediates produced or the oxidation of the resulting products. When performed as such, the irradiation resulted in a twofold increase in the weight-average molecular weights of the starch polysaccharides compared to the non-irradiated starch. The obtained results, reflecting the effects of 5 h of UV radiation exposure on wheat starch, suggest that this radiation has a significant effect on the starch granule. Taking into account the rapid decrease in M\({}_{\mathrm{w}}\) of the polysaccharide chains, it suggests that wheat starch \begin{table}
\begin{tabular}{l c c} \hline \hline \multirow{2}{*}{**Starch \({}^{**}\)**} & **M\({}_{\mathrm{w}}\times\) 10\({}^{7}\)** & **R\({}_{\mathrm{g}}\) [nm]** \\  & **Whole Peak** & **Whole Peak** \\ \hline
**Spelt** & 0.82 \(\pm\) 0.24 \({}^{\mathrm{a}\mathrm{b}}\) & 66.8 \(\pm\) 3.0 \({}^{\mathrm{a}}\) \\
**Spelt-5** & 0.57 \(\pm\) 0.03 \({}^{\mathrm{a}\mathrm{b}}\) & 86.2 \(\pm\) 5.7 \({}^{\mathrm{b}}\) \\
**Spelt-15** & 1.27 \(\pm\) 0.45 \({}^{\mathrm{b}\mathrm{c}}\) & 78.1 \(\pm\) 5.0 \({}^{\mathrm{a}\mathrm{b}}\) \\
**Spelt-25** & 0.59 \(\pm\) 0.07 \({}^{\mathrm{a}\mathrm{b}}\) & 65.1 \(\pm\) 4.8 \({}^{\mathrm{a}}\) \\
**Spelt-50** & 1.68 \(\pm\) 0.20 \({}^{\mathrm{c}}\) & 87.8 \(\pm\) 3.6 \({}^{\mathrm{b}}\) \\ \hline
**Wheat** & 2.31 \(\pm\) 0.35 \({}^{\mathrm{D}}\) & 77.4 \(\pm\) 3.2 \({}^{\mathrm{C}}\) \\
**Wheat-5** & 0.29 \(\pm\) 0.04 \({}^{\mathrm{A}}\) & 71.6 \(\pm\) 2.8 \({}^{\mathrm{B}\mathrm{C}}\) \\
**Wheat-15** & 1.58 \(\pm\) 0.13 \({}^{\mathrm{C}}\) & 96.1 \(\pm\) 3.7 \({}^{\mathrm{D}}\) \\
**Wheat-25** & 0.82 \(\pm\) 0.04 \({}^{\mathrm{B}}\) & 67.6 \(\pm\) 3.0 \({}^{\mathrm{A,B}}\) \\
**Wheat-50** & 0.70 \(\pm\) 0.05 \({}^{\mathrm{A,B}}\) & 68.4 \(\pm\) 2.5 \({}^{\mathrm{A,B}}\) \\ \hline \hline \end{tabular} \({}^{\star}\)Calculated from three repetitions of measurement \(\pm\) standard deviation; ** Values indicate the time of exposure [hours]. The parameters in columns marked with the same letters (\({}^{\mathrm{a},\,\mathrm{b},\,\mathrm{A},\,\mathrm{B}}\), etc.) did not differ statistically at the confidence level of \(p<0.05\).  
\end{table} 
Table 1: The M\({}_{\mathrm{w}}\) (g/mol) and Rg values of UV irradiated native spelt and wheat starches \({}^{\star}\). grains are more sensitive to this radiation. This fact may be due to the lower lipid content of the native wheat starch compared to spelt starch. According to the authors, lipids have a protective effect on the starch granule and are the first to absorb UV radiation [21].