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.