Effect of Green Coffee Polyphenols on Properties of Protein Hydrolysates in Model Systems

Abstract

Polyphenol-amino acid interactions during food processing cause deterioration of nutritional and organoleptic quality of proteins, peptides or free amino acids. This limits the possibility to supplement food reach in proteinaceous compounds in phenolics. The aim of this study was to assess, if encapsulation of hydroxycinnamic acids (HCAs) from green coffee, using inclusion in β-cyclodextrin (β-CD), may limit HCAs-peptides interactions. Three protein hydrolysates: from egg ovalbumin (EOH), whey protein (WPH) and soy protein (WPH) were used. After interactions a higher increase of molecular mass and degradation of essential amino acids, as well as limitation of proteolytic digestion were reported, compared to the controls. The interactions with HCAs contributed to a higher radical scavenging capacity and color deepening of peptides. Inclusion of HCAs in β-CD resulted in the limitation of HCAs-peptide interactions. Supplementing of HCAs to foods in a form of inclusion complexes could be a promising solution for reducing HCAs-peptides interactions. Practical Application Functional foods are often supplemented with polyphenols and proteinaceous compounds, such as protein isolates or protein hydrolysates. The interactions that occur between them during food processing and storage could significantly decrease their nutritional and pro-health properties. Thus it could be beneficial to protect polyphenols from these disadvantages changes by encapsulation. One of the possible solutions could be nanoencapsulation of polyphenols by inclusion into β-cyclodextrin (β-CD). This possibility was confirmed for hydroxycinnamic acids from green coffee. The interactions between them and three different protein hydrolysates were limited and, as a result, disadvantageous changes of nutritional and physicochemical properties were decreased.