Binding properties of 2-pentyl pyridine to soy protein as measured by solid phase microextraction

The binding properties of 2-pentyl pyridine (2-pp) were investigated for soybean protein isolates (SPI) and the beta-conglycinin and glycinin soy protein fractions. The glycinin fraction had the highest binding affinities for 2-pp, followed by beta-conglycinin fraction, and then SPI. More 2-pp was bound by SPI and beta-conglycinin or glycinin fractions under alkaline conditions than under neutral conditions, which exhibited more binding than acidic conditions. More 2-pp was also bound at high temperature (74 °C) than at 25 °C, but greater binding affinity of 2-pp was observed at 4 °C than at 25 °C. With increased NaCl concentrations, the binding affinity of 2-pp decreased. Exposure to UV light increased binding of 2-pp to all types of soy protein.