# Assessment of the Baking Properties of Rye Flour Based on the Polysaccharide Content and Properties
## 3 Results
### The Parameters Related to the Pentosan-Pentosanolytic Complex
#### 3.2.2 Swelling Curve Parameters
Suspensions from the tested rye flour samples produced in 2019 and 2020 were characterized by similar levels of V\({}_{30}\) and V\({}_{42}\) (average V\({}_{30}\): 391 and 372 AU as well as V\({}_{42}\): 309 and 317 AU, respectively). The final viscosity after holding the suspension at 42 \({}^{\circ}\)C for 30 min (FV\({}_{42}\)), depending on the content and properties of the pentosans, as well as the degree of enzymatic degradation [57], ranged from 95 to 385 AU (Figure 4). The low-extract rye flour samples were characterized by a significantly lower FV\({}_{42}\) compared to the high-extract rye flour samples (on average, 142 and 280 AU, respectively). The flours produced in 2019 also had a significantly higher FV\({}_{42}\) value compared to the rye flour samples produced in 2020 (on average, 187 and 235 AU). Similar to the previous study by [PERSON] et al. [48], a significant positive correlation was found between all the viscosity indicators read from the swelling curve and the TPC, WSPC, and WIPC. Also, a study conducted by [PERSON] et al. [58] revealed significant correlations between the V\({}_{30}\), V\({}_{42}\), and TPC. It should be noted that the viscosity of the rye flour suspension is significantly influenced not only by the content of pentosans but also by their molecular weight and degree of branching. With the same pentosan content, suspensions made from flour containing pentosans with a higher molecular weight and a greater degree of branching are characterized by higher viscosities when examining the swelling curve [59; 60]. The changes in viscosity during 30 min of holding the suspension at 42 \({}^{\circ}\)C, determined as the differences in the logarithms of the viscosity decrease at 42 \({}^{\circ}\)C, allowed for an  
Figure 4: Viscosity obtained from the swelling curve test: initial (V\({}_{30}\)), when the sample reached 42 \({}^{\circ}\)C (V\({}_{42}\)) and final after holding the suspension at 42 \({}^{\circ}\)C for 30 min (FV\({}_{42}\)) obtained from the swelling curve test for the studied rye flour samples (sample codes as in Figure 1). indirect assessment of the activity of the enzymes that degrade pentosans [25; 61]. The rate of decrease of the suspension viscosity is interpreted as an indicator of the decomposition of soluble pentosans, both those present in flour and those formed in the bread baking process as a result of the transformation of insoluble pentosans into a soluble form [56]. It is unfavorable for rye flour to be characterized by a high value of the logarithmic decrease in viscosity at a temperature of 42 \({}^{\circ}\)C and also a high initial viscosity at 30 \({}^{\circ}\)C. Such parameters are usually characteristic of flour with a high content of pentosans, which undergo numerous transformations during kneading, fermentation, and in the first phase of baking. Insoluble pentosans are mainly transformed into a soluble form. Soluble pentosans, both present in flour and those formed as a result of transformations, undergo acid hydrolysis [59; 62]. If the hydrolysis of soluble pentosans is too intense, the dough becomes too intensively loosened during fermentation due to a decrease in dough efficiency related to a reduction in the ability of pentosans to bind water [63]. Although rye flour has high pentosanolytic activity, the conversion of insoluble pentosans into a soluble form during dough kneading and fermentation occurs to a greater extent; however, this process does not have a positive impact on the quality of bread. This is mainly caused by too high a degradation of soluble pentosans, which adversely affects the volume of bread and the crumb structure. In flour characterized by the optimal activity of enzymes, there is an appropriate ability to bind water, because the content of soluble pentosans increases, as well as a decrease occurring in the amount of soluble pentosans with a high molecular weight and an increase in the amount of soluble pentosans with a low molecular weight [64].