Role of pectin and haze particles in membrane fouling during cold microfiltration of apple cider

The role of pectin in membrane fouling during cold MF of apple cider was investigated. Clarified apple juice with four different concentrations of pectin was subjected to cold MF, at pore sizes above 0.45 μm. The experimental data shows that pectin plays a significant role in membrane fouling, and its fouling effect increased with increasing concentration. The association of pectin with polyphenols and proteins, which results in colloidal haze particles with low surface electrical charge, seems to be the major factor in fouling during cold MF of apple cider. Depectinization was beneficial to MF with pore sizes below 0.45 μm, for which fouling is dominated by cake layer formation. Depectinization had a negative effect on MF flux for pore sizes above 0.8 μm, since the size reduction of haze particles accentuated pore constriction and blockage, which dominate fouling in large pore MF. These findings have practical implications for the development of efficient, commercially viable, cold MF processes for minimally processed apple cider.