Complexation between phenolic compounds and soy protein isolate: Effects on protein structure

Complexes are formed between phenolic compounds in hydro-ethanol pomegranate peel extracts and soy protein isolate in alkaline environment (pH 9) with pre-treated protein at 90 ℃. Three different extract concentrations have been used (1, 2 and 3%). The protein-phenol interaction in the complexes has been analyzed through structural, morphological and functional changes using electrophoretic (SDS-PAGE) and spectroscopic techniques (UV-Vis and FT-IR) along with scanning electron microscopy. The results indicate changes in the secondary structure of proteins and a strong affinity to bind with polyphenols. The data forms a theoretical basis for the interaction between soy protein isolate and polyphenolic compounds in extracts of pomegranate peels. It can be useful in the development of phenol-rich, soy-based functional foods and active biomaterials.