Acceleration of precipitation formation in peach juice induced by high-pressure carbon dioxide.

Peach juice was treated by high-pressure carbon dioxide (HPCD). HPCD-induced acceleration of precipitation formation in peach juice was observed. Particle size distribution (PSD), pH, zeta-potential, protein and total phenols, pectin methylesterase (PME) activity, pectin and calcium, and viscosity in juice, contributing to the precipitation formation, were studied. HPCD resulted in a significant alteration of juice PSD pattern; the acceleration of the precipitation formation concurred with this alteration. A significant decrease of protein and a declining trend of total phenols were obtained, the contents of pectin and calcium were not changed, and the difference in PME activity in juice was not significant after HPCD. HPCD led to higher increase in juice viscosity, whereas pH and the absolute value of zeta-potential declined during HPCD. These results suggested that the pH and absolute value of zeta-potential declines induced the coagulation of protein and decrease of particle charge, responsible for the acceleration of the precipitation formation.