Sodium Magnesium Chlorophyllin is produced by alkaline hydrolysis (saponification) of natural chlorophyll to remove the phytol tail. This creates water solubility while retaining the original magnesium centre.
Unlike copper chlorophyllin (E141), this form contains no added metals and is considered more 'natural'. However, it is less stable than the copper derivative. Used where a fully natural green colouring is required.