# Physicochemical and Molecular Properties of Spelt and Wheat Starches Illuminated with UV Light
## 3 Results and Discussion
### Determining the Size of the Structural Units of Amyloidectin  
Samples of native and UV-irradiated starches were subjected to isoamylolysis. The enzyme isoamylase hydrolyzes \(\alpha\)-1,6-glycosidic bonds, breaking down the amylopectin macromolecule into straight chains. The molar mass (M\({}_{\mathrm{w}}\)) distribution of the amylopectin polysaccharide chains in the debranched starches was determined using the HPSEC-MALLS-RI method. The obtained chromatograms were divided into fractions depending on the molecular weights. According to [24], polysaccharide chains with molecular weight values of M\({}_{\mathrm{w}}\) < 2000 are classified as A-type amylopectin side chains, while polysaccharide chains with higher molecular weights are classified as B\({}_{1}\), B\({}_{2}\), and B\({}_{>3}\). The chromatograms were divided arbitrarily into fractions belonging to the type of A-chains, B-chains as well as amylose-type chains. For the polysaccharide chains of the individual fractions, the weight-average molecular weight and the percentage mass of a given fraction in the total weight of the sample were determined. The M\({}_{\mathrm{w}}\) numbers of the amylopectin structural units of the spelt and wheat starches are summarized in Tables 2 and 3, respectively. Figures 13 and 13 also represent the percentage of each amylopectin fraction (m%) in the total sample weight. Amylose chains were assigned in accordance with the obtained chromatograms for the separated fraction (III) of spelt starch. The B\({}_{2}\) and B\({}_{\geq 3}\) chains were included in fraction (II). However, short type A and B\({}_{1}\) chains were assigned to fraction (I). The percentage of each type of chain in the total amylopectin weight is shown in Figure A1. The spelt sample starch contained a high proportion of type A chains (88%) [16]. As the exposure time increased (5-50 h), the percentage of this type of chain decreased. The lowest short chain content was observed in spelt starch irradiated for 50 h. At the same time, this exposure resulted in the highest number of longer chains, both type B and amylose chains. The conducted experiments for wheat starches allowed for the isolation of a greater number of fractions containing chains characteristic of the amylopectin molecule. Fraction (V) was formed by long polysaccharide chains close to amylose units. Long type B\({}_{\geq 3}\) chains were distinguished in fraction (IV), while type B\({}_{1}\) and B\({}_{2}\) chains were assigned to fractions (III) and (II). Type A chains constituted Fraction (I) (Table 3). The percentage share of each fraction in the total mass of the native and UV irradiated wheat starch sample is summarized in Figure A2. The fraction of amylose chains accounted for a small percentage of all chains; however, the largest number of such chains was observed in starch modified for 5 h. Meanwhile, for the same modified starch sample (wheat-5), the highest percentage of type A chains (Fraction I) was identified. Exposing wheat starch for 5 h resulted in polysaccharide chains with the lowest weight-average molecular weight (2.9 \(\times\) 10\({}^{6}\) g/mol), hence the high percentage of the shortest chains. It is worth mentioning that the proportion of B\({}_{\geq 3}\) chains was the highest for natural starch and for starch irradiated for 15 h, for which the M\({}_{\rm w}\) of polysaccharides exhibited the highest values. The fact that the share of A-type chains for amylopectin fraction (native spelt) was two times higher than that of wheat starch amylopectin may affect the distribution of amylopectin side chains of the irradiated starch.