Exploring the interactions between blackcurrant polyphenols, pectin and wheat biopolymers in model breads; a FTIR and HPLC investigation

This study explores the interactions between added blackcurrant polyphenols (PPs) and pectin, as well as different bread components in model bread systems. A series of model breads containing flour, yeast, sugar, salt, oil and water, with/without added pectin and blackcurrant PP extract, were prepared and characterised. Results show that adding PPs in addition to pectin increased the total extractable PP content and antioxidant activity of the breads, and decreased the proportion of unextractable high molecular weight proteins (detected by size exclusion-HPLC). The composition of bread formulations influences the amount of anthocyanins, especially delphinidin-3-o-glucoside and delphinidin-3-o-rutinoside, which are retained after bread baking. Replacing flour with starch and gluten, adding blackcurrant PP extract and pectin, or removing bread components (oil, salt or the mixture of yeast and sugar), caused changes in the bread gluten conformations related to Amide I and II bands (revealed by FTIR), as well as the extractability of PPs and proteins (revealed by HPLC).