Effects of concentration of flavor compounds on interaction between soy protein isolate and flavor compounds

Headspace-solid-phase microextraction/gas chromatography-mass spectrometry, static headspace/gas chromatography, fluorescence spectroscopy, zeta potential, particle size, and surface hydrophobicity were used to obtain comprehensive and precise information on binding properties. Klotz and Hill binding models were compared at low and high concentration of flavors binding to soy protein isolate (SPI) to estimate binding parameters in aqueous solution. These results show the low molar binding ratio of flavor bind to SPI induced almost no conformational changes in SPI, which indicates linear binding; the high molar binding ratio induced conformational changes in SPI (citronellal > citronellyl acetate > citronellyl propionate > citronellol), indicating nonlinear binding; salting out of α–pinene, and terpinene were analyzed at low and high molar ratios of flavors binding to SPI. These results indicate the necessity of multiple analytical methods to accurately assess interactions between flavor compounds and proteins in food and contribute to current knowledge regarding flavor profiles.