Effects of the Extraction Conditions on Functional and Structural Characteristics of Proteins from Fenugreek Seeds

Abstract

The study aims to optimize the extraction process and characterize the proteins found in fenugreek seeds. The water and oil holding capacities, coagulated protein content, foaming, and emulsification properties of the isolated proteins were investigated under all extraction conditions. Also, solubility, molecular weights, structural and thermal properties were determined. In the extraction processes carried out at different pH (pH 6.0–12.0) and solid:solvent ratios (20–60 g/L), it was determined that the highest extraction yield (94.3 ± 0.3%) was achieved when the pH was 11.47 and the solid-solvent ratio was 34.50 g/L. Three distinct bands (46, 59, and 80 kDa) in the range of 22–175 kDa were determined for the fenugreek seed protein isolate obtained under optimum extraction conditions. Protein secondary structures were determined using Fourier Transform Infrared (FT-IR) spectra and it was determined that β-sheet structures were highly present. In addition, denaturation temperature and denaturation enthalpy were calculated as ~119 °C and 28 mJ/g, respectively.