Concentration and purification of soluble pectin from mandarin peels using crossflow microfiltration system

A crossflow microfiltration process was developed to concentrate and purify soluble pectin extracted from the mature citrus peel. The extracted pectin solution was concentrated with the crossflow microfiltration using a 0.2 μm regenerated cellulose membrane. As a result of crossflow microfiltration, the galacturonic acid content of pectin increased from 68.0 to 72.2% while the recovery yield of pectin decreased from 10.5 to 9.9%. In addition, the volume of ethanol used for the recovery of pectin could be reduced to 25%. To purify pectin further, the concentrated pectin extracts was washed using the fed-batch type diafiltration system. By diafiltration, the galacturonic acid content of pectin increased from 72.2 to 75.6%. The yield of pectin, however, decreased from 9.9 to 9.4% at six volumes of diafiltration. The diafiltration process was also effective to remove flavonoids, polyphenols and carotenoids, which were impurities in pectin products. Therefore, the crossflow microfiltration system could be efficiently used for concentration and purification of pectin.