Interactions and complex stabilities of grape seed procyanidins with zein hydrolysate

Summary The objective of this paper was to investigate the complex of grape seed procyanidins (GSP) with zein hydrolysate (ZH). The interaction was determined using isothermal titration calorimetry (ITC) and fluorescence spectroscopy. The particle size, ζ‐potential, scanning electronic microscopy (SEM) and stability test of the ZH‐GSP complex were measured. The results of ITC, particle size and SEM suggested that there was a hydrogen bond‐dominated interaction between GSP and ZH, and the ZH‐GSP complex presented as a spherical shape with particle size of 234 nm, polydispersity index of 0.11 and ζ‐potential of −46.4 mV. The results of the fluorescence spectroscopy showed that the fluorescence quenching effect of GSP on ZH was GSP concentration‐dependent and the quenching process was mainly static quenching. The ZH‐GSP complex had better physical stability in aqueous solution, and their solution was more stable than GSP solution under illumination and high‐temperature treatment at 75°C.