applied sciences  
Article  
Preliminary Study on the Influence of the Polyphenols of  
Different Groups on the Digestibility of Wheat Starch,  
Measured by the Content of Resistant Starch  
[PERSON], [PERSON],*D, [PERSON] and [PERSON]  
Department of Human Nutrition and Dietetics, Faculty of Food Technology, University of Agriculture in  
Krakow, Aleja Mickiewicza 21, 31-120 Krakow, Poland Department of Carbohydrates Technology and Cereals Processing, Faculty of Food Technology,  
University of Agriculture in Krakow, Aleja Mickiewicza 21, 31-120 Krakow, Poland Correspondence: [EMAIL_ADDRESS]; Tel: +48-12-662-48-15  
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far, polyphenols have been found to affect starch digestion. Polyphenols interact with \(\alpha\)-amylase mainly through hydrogen bonds between hydroxyl groups and the enzyme's active site and through hydrophobic interactions between polyphenols' aromatic groups and the enzyme [10]. Binding of flavonoids to amylase follows a static mechanism; flavonoids bind near the enzyme's active site [11]. Polyphenols can also interact with amylose through hydrogen bonding and hydrophobic interactions to form indigestible complexes [12]. Starch also appears to promote interactions with high-molecular-weight polyphenols, such as tannins [13]. There are a number of studies on the effects of polyphenic compounds found in raw materials of plant origin and added to foods to increase their functional value [5]. Various products enriched with polyphenols were characterized by their effect on reducing starch digestibility in vitro (bread--black rice extract; cookies--pomegranate peel, apple peel; wheat bread--green tea extract, grape seed extract, resveratrol, freeze-dried fruits of various wild shrubs, baobab fruit extract; multifins--mango waste products) [5, 14, 15, 16]. In the literature, the data on which groups of polyphenic compounds (phenolic acids, flavones, flavanones, flavanols, anthocyanins) reduce the digestibility of starch, as well as their functional properties, are insufficient. There are other bioactive compounds such as dietary fiber, fat, proteins in plant waste products or plant raw materials containing different groups of polyphenic compounds that can also affect the above-mentioned parameters (starch digestibility). Hence, first of all, it is difficult to clearly determine what the actual effect of polyphenols is, and especially which groups of these compounds show the best effect. The proposed research and approach to the problem of starch digestibility are innovative and have not been presented in the scientific literature so far. The objectives of the proposed research were (_i_) to see if there are differences between different groups of polyphenols in reducing wheat starch digestibility, as measured by resistant starch (RS) content; (_ii_) to find the most effective group of polyphenols in this regard; and (_iii_) to find the most effective compound.