Selective removal of iron from grape juice using an iron(III) chelating resin

This work reports the results of iron removal from grape juice with an iron(III) chelating resin in both batch separation and column separation processes. The separation experiments indicated that the iron(III) chelating resin removed iron selectively and effectively from grape juice. The iron content in grape juice was reduced from 1000 ppb to 2 ppb with a batch separation at a ratio of 1 g of the resin to 100 ml of grape juice. By using a sequential multi-batch separation process or a column separation process, the iron level in grape juice could be reduced to 1 ppb with the iron(III) chelating resin. It was found that selective removal of iron was completed within 3 h. The chelating resin did not remove other metals such as Co, Mg, Ca, Zn, Mn, K and Na in the grape juice. Mo and Cu, however, were partially removed. Preliminary microbial tests indicated that the growth of the wine yeast (Saccharomyces cerevisiae) was partially inhibited in the iron-deficient grape juice. (C) 1997 Elsevier Science B.V.