# Glycaemic Index of Bakery Products and Possibilities of Its Optimization
## 5 Conclusions  
The problem of diabetes, especially type 2 diabetes, is an extremely serious global problem and affects most of the parts of the world described as developed. It is, of course, also fully applicable to the Czech Republic and the whole of Central Europe, whose population in many respects shares similar dietary habits. Bread and bakery products, or pasta, are the most important source of starch in the diet of the population, with the vast majority of the total starch content of these products occurring in digestible form, mainly as RDS and partly as SDS. The contribution of starch to the disease itself and its complications is undisputed. The GI of standard breads and pastries is most often in the range 60-75, with 70 being the threshold for labelling a product as a high GI food. Conversely, the threshold below which foods are labelled as low GI is 55. Traditional Central European bread is a mixed rye-wheat or wheat-wheat bread leavened with rye sourdough spontaneously developed from the natural microflora of rye bread flour. In modern industrial production, spontaneous vital sourdoughs are being replaced by more stable, acidic vital yeasts initiated by BMK starter cultures, and the dough is leavened by the addition of yeast [137]. The emphasis on the use of yeasts is increasing with the growing awareness of their nutritional benefits. The use of rye, but also wheat sourdoughs, sourdoughs from gluten-free cereals and pseudocereals (rice, sorghum or buckwheat flours) and legume flours is expanding into the production of non-traditional bakery products [138]. Similar to the use of leavening, the use of many types of hydrothermal treatment of raw materials in aqueous suspensions is expanding, both for whole grains for the production of multi-grain types of bread and for bakery products, cereal meal and flours. As with leavening, these processes are rightly considered important not only as a means of improving the sensory properties of bread and pastry but also, and in particular, for their positive nutritional effects. To summarize the nutritional effects demonstrated for the leavening and hydrothermal treatment of raw materials, these are mainly the production of certain nutritionally important substances (e.g., organic acids and exopolysaccharides in leavening) or the effect of both technological processes on increasing the bioavailability of fibre components and accompanying substances (phenolic compounds, minerals, vitamins, etc. [139]. The effect of the use of sourdoughs and hydrothermally treated suspensions not only occurs via their addition to the dough itself, but also by their action at other stages of the technological process of bread and pastry production, i.e., during the maturation of the dough and during heat treatment (baking), cooling and storage. What remains unanswered, however, is the influence of these desirable technological processes on the final GI values of bread and pastry. The pathways leading to a reduction in the GI of a bakery product are firstly to reduce the relative starch content, and secondly to increase the proportion of some type of resistant RS starch in the total starch content. The hydrothermal treatment of cereal suspensions, fermentation at the leavening or pre-fermentation stage, and the subsequent processes of dough maturation, mode of heat treatment, chilling or freezing, storage, finishing, and pre-consumption treatment also have an impact on the fate of starch and changes in its digestibility, and on the transitions between RDS, SDS and RS, and thus have a significant impact on the final GI of the bakery product. The impact of many of these is ambiguous and varies substantially depending on many specific conditions. Conceptualization, P.S., M.S., A.S., R.B., I.S., E.S. and V.P. ; writing--original draft, P.S., M.S., A.S., R.B., I.S., E.S. and V.P. ; writing--review and editing, P.S., M.S., I.S., E.S. and V.P. All authors have read and agreed to the published version of the manuscript. This research received no external funding.