## 4 Discussion
In the present study, bread storage lasted 3 days, which is the typical time, simulating the consumer's method of storing fresh bread at home. Moreover, bread samples were stored at room temperature (22 \({}^{\circ}\)C) and wrapped only in food paper, without any other specific conditions. An important and new issue revealed in the presented research is the phenomenon of the maintenance of most texture parameters in samples prepared with the addition of selected strains of \(L\)_plantarum_ to bakery sourdough. Interestingly, in the case of the control sample (SBY), these parameters changed unfavourably during the 3 days of storage. This can be explained by the fact that \(L\). _plantarum_ bacteria, which were added to the sourdough samples, can produce exopolysaccharides (EPS), which have rheological properties that improve the texture and consistency properties of some foods--including bread [37]. LAB properties for EPS production were tested by [PERSON] et al. [38] in their study aimed at sourdough bread development. They used sourdough produced with and without the addition of EPS-synthesizing bacteria. In the research, they noticed that products containing EPS synthesised by bacteria were characterised by better durability and prolonged freshness. Also, [PERSON] et al. [39] used LAB strains (_Lactobacillus delbrueckii_ subsp. _bulgariicus_ LB18; \(L\). _delbrueckii_ subsp. _bulgaricus_ CNRZ 737, and \(L\). _delbrueckii_ subsp. _bulgaricus_ 2483) with a high ability to synthesise EPS. The authors noted that a higher level of EPS obtained from LAB could result in greater water retention, leading to improved properties of the crumb structure of bread and a longer shelf life. Another factor that affects the extension of the shelf life of bread is the acidification of the environment by the LAB contained in sourdough [40]. Acidification of the environment leads to a decrease in the activity of proteases and amylases, which directly affects the reduction in the degradation of protein and starch fractions of bread, thus extending its shelf life. The sensory evaluation was carried out to characterise the sensory profiles of the bread samples and assess whether the introduction of new bacterial strains would significantly affect the taste and smell of the product. To answer this question, sensory evaluation was carried out on fresh bread samples, without continuing the research on stored samples, unlike in instrumental texture tests. It was found that the addition of selected \(L\). _plantarum_ strains affected the sensory properties of the bread samples. Although all samples represented the typical flavour of bread, they were different in terms of consistency. The decrease in the elasticity of the O20 sample was most likely due to the properties of \(L\). _plantarum_ enzymes. It has been proven that some strains of \(L\). _plantarum_ can synthesise proteolytic enzymes and that this is a strain-dependent feature [41]. The O20 and O19 strains were tested for enzymatic activity and several selective arylamidases were found to show activity on leucine, valine, and trypsin [17]. These enzymes can integrate into the structures of peptides and amino acids, reducing their properties [42]. In some studies, such propertieshave been used to reduce the allergenic effects of gluten through its bacterial enzymatic degradation. Unfortunately, the ongoing proteolysis harmed the texture properties of bread, causing its less stable structure, reducing its elasticity, and increasing its softness [43; 44]. On the other hand, the SBY sample had the lowest humidity. This result may have been directly influenced by the previously mentioned properties of _L. plantarum_ bacteria, which are able to EPS synthesis. These substances are characterised by high water absorption and very good rheological properties [45]. Due to the lack of addition of specific _L. plantarum_ bacteria to the SBY sample, EPS were probably not formed in the same amount as in samples with the addition of a huge amount of _L. plantarum_ strains.