## 4 Discussion
The molecular structure of hesperidin indicates that it is a polyphenol with potent inhibitory activity, although not as strong as those previously mentioned, as is kaempfer. The most effective impact of SDS, RS, and SDI values of wheat starch was observed with the addition of kaempfer at a dose of 10 mg when administered prior to starch pasting (\(p<0.05\)). Similarly, the addition of kaempfer exhibited the greatest inhibitory activity at the same dose when added after starch pasting in the case of the SDS value of potato starch (\(p<0.05\)). The weaker inhibitory activity abilities were inferred in the cases of naringenin and \(p\)-couamaric acid [37; 64]. The most efficacious concentration of naringenin (20 mg) was observed for the RS content of maize starch when added prior to its pasting and for the SDS and SDI of potato starch when added subsequent to its pasting at a dose of 10 mg (\(p<0.05\)). With regard to \(p\)-couamaric acid, it did not demonstrate the most effective results in any case. The polyphenol with the weakest inhibitory activity, based on its molecular structure, was _trans_-ferulic acid [37]. Nevertheless, the present study yielded the highest SDS value of rice (addition before starch pasting) and maize starch (addition after starch pasting) for _trans_-ferulic acid (10 mg) (\(p<0.05\)). In our study, we have proved that epigallocatechin gallate at a dose of 20 mg was the most effective polyphenol in reducing the value of the estimated glycemic index across all starch types. This finding constitutes useful and crucial implications for dietary recommendations, especially for people suffering from impaired carbohydrate metabolism, including type 2 diabetes. The effect of polyphenol-rich foods (e.g., green tea, coffee, and berries) on glycemic control and insulin sensitivity has already been researched, particularly in relation to diabetes. Concerning green tea, the results are mixed, with some studies showing no effect on glycemic markers, while others suggested modest reductions in fasting glucose. Studies indicatedthat coffee, especially due to chlorogenic acid, may influence glucose absorption and gastrointestinal hormone secretion, but overall evidence of its effect on glucose homeostasis is limited. Berries may delay glucose absorption and reduce postprandial insulin responses, but their overall effect on long-term glycemic control is not well-established [67]. Therefore, it would be interesting to conduct clinical research on the impact of the starches with added polyphenols (that gave the best results in the present study) on postprandial glycemia. The possible limitations of the conducted study may include the fact that the food consumed is usually a mixture of many nutrients (i.e., protein, fats, dietary fiber), not just starch, and those substances may affect the rate of starch digestion. Moreover, the tested polyphenols differ in their solubility and hence may have different bioavailability in the living organisms. Most of those tested were hardly soluble in water. For this reason, DMSO was used, but it is impossible to apply such a solvent in the food production process. And finally, there is a huge range of polyphenols found in food products, and it is impossible to test all of them at the same time. It is even probable that the most popular foods may not necessarily be the most effective ones in terms of their ability to inhibit starch digestion.