Advanced assessments on innovative methods to improve the bioaccessibility of polyphenols in wheat

Polyphenolic compounds (PCs) are a group of natural antioxidants found in plants. Because most of the PCs exist in bound form in wheat, the efficiency of the solvent extraction method is very low. In general, there are three types of methods used to extract the bound PCs or convert them to free ones and as a result, increase the bioaccessibility of these non-extractable compounds. Although chemical extraction is the most common method used in this way, the enzymatic treatment also accomplishes with less efficiency to break down the linkages between cell wall components and PCs. In recent years, the use of solid state fermentation have been growing up and several microorganisms have been used to produce hydrolyzing enzymes and convert bound PCs to extractable ones. By using this method, the biological effects of the sample originated from the antioxidant property of PCs can be increased in fermented wheat cultivars. This paper provides an overview of different modifications and treatments emphasizing the effect of solid state fermentation as an alternative method for increasing the content of free PCs in wheat.