Impact of protein-phenolic interaction on the stability and bioaccessibility of phenolic compounds in extract of pomegranate peels

¹ Department of Cryobiology and Biologically Active Substances, Institute of Cryobiology and Food Technologies, Agricultural Academy 1407 Sofia, Bulgaria
² Department of Food Technology, Institute of Cryobiology and Food Technologies, Agricultural Academy, 1407 Sofia, Bulgaria

^* Corresponding author: asolak@abv.bg

Abstract

The objective of this research is to analyze the influence of soy protein isolate (SPI) on the stability and bioaccessibility of phenolic compounds in pomegranate peel extract (ePGP) in a complexes formed between them. The complexes (SPI-ePGP) are formed in an alkaline conditions (pH 9) with pre- treated protein at 90℃ using different extract concentrations (1, 2 and 3%). Bioaccessibility is determined by monitoring changes in total phenolic content, flavonoids, and total monomeric anthocyanins using an in vitro digestion model. The stability of phenolic compounds is determined after treating the SPI-ePGP and the ePGP with light and heat. The results from the studies indicate substantial changes in phenolic compound levels during two of the phases of simulated digestion. High phenolic compound levels after gastric digestion go down significantly after intestinal digestion. SPI increases light and thermal stability of polyphenols in complexes. The data illustrates the impact of the protein-phenolic interaction on the stability and bioaccessibility of phenolic compounds. It also builds a theoretical foundation for developing functional foods or active materials based on soy protein isolate and extract of pomegranate peels.