# Modification of Mineral Content in Bread with the Addition of Buckwheat Husk
## 3 Results and Discussion
### Mineral Contents in the Tested Bread Samples
This observed increase is in agreement with our findings, which proved that buckwheat husk addition improved the contents of macrominerals like potassium and magnesium. In contrast to our study on buckwheat husk addition to breads, [PERSON] et al. [25] did not observe significant changes in the levelsof microminerals such as iron, zinc, and manganese. This may have resulted from the different mineral compositions of the additives used for enrichment. Buckwheat hull is rich in trace minerals, which explains the increase in manganese and copper in the enriched bread we analyzed, while green banana flour is richer in macrominerals. Although the mechanism of the observed changes in the profile of minerals in the tested breads samples was not analyzed in this study, our previous studies results [26; 27] and literature data allowed us to make certain conclusions. During food preparation processes including cooking, processing and storage, mineral components can undergo various changes that affect their bioavailability and the final composition of the product [26; 28; 29]. During food processing, mineral components can interact with other food components, making them unavailable for digestion. Fiber, particularly soluble fiber, can bind certain minerals, potentially affecting their absorption in the digestive tract [30]. The binding effect depends on the type of fiber and its concentrations [31]. The insoluble fraction of this component mainly consists of non-fermentable cellulose, hemicellulose and lignin, while the soluble fiber is composed of easily fermentable pectins, gums and mucilages. Cellulose and lignin have been shown to have a high metal binding capacity, but the NDF (neutral detergent) and ADF (acid detergent) fractions act at a physiological level to improve digestibility and mineral availability, as well as influencing a range of nutrient interactions [29; 32]. [PERSON] et al. [33] add that many in vitro studies have not shown a negative effect of fiber on mineral bioavailability and in some cases have even reported an increase in mineral absorption. This may be due to the fermentation of some fiber fractions occurring in the intestines, resulting in the release of previously bound minerals and their absorption in the large intestine. Both the wholemeal flour and buckwheat husk used in the present study for bread preparation were rich in fiber [34]. Fiber can form complexes with minerals such as calcium, iron, and zinc, which may reduce their bioavailability [31], which was also confirmed in our study. Moreover, plant products also contain elements other than fiber such as phytates and some fractions of polyphenols, which are often more potent inhibitors of mineral absorption. This makes the question of the bioavailability of minerals in plant products even more complex [35; 36]. In our previous study [24; 37], we showed that the interactions between these components significantly depend on the heat treatment parameters of buckwheat grains. A high temperature can inactivate endogenous phytase, which prevents the breakdown of phytates and the release of many minerals. On the other hand, phytates can be degraded during hydrothermal treatment, which releases minerals and increases their bioavailability [37; 38]. Phenolic compounds also undergo thermal degradation, resulting in additional mineral release. The intensity of these changes is greater at higher heating temperatures [35]. The influence of thermal processes is equally important in the context of buckwheat hull extraction, since the process of dehulling the seeds under industrial conditions takes place after heating (intensively in the production of roasted buckwheat and gently in the case of unroasted buckwheat). We indicated that a shorter hydrothermal process conducted at a lower temperature was significantly more beneficial for the availability of buckwheat minerals (especially Mn and Mg) than a longer roasting process conducted at a higher temperature (which had particularly adverse effects on Zn and Cu) [37].