Consists mainly of the partial methyl esters of polygalacturonic acid
and their sodium, potassium, calcium and ammonium salts; obtained
by extraction in an aqueous medium of appropriate edible plant
material, usually citrus fruits or apples; no organic precipitants shall
be used other than methanol, ethanol and isopropanol; in some
types a portion of the methyl esters may have been converted to
primary amides by treatment with ammonia under alkaline
conditions. Sulfur dioxide may be added as a preservative.
The commercial product is normally diluted with sugars for
standardization purposes. In addition to sugars, pectins may be
mixed with suitable food-grade buffer salts required for pH control
and desirable setting characteristics. The article of commerce may
be further specified as to pH value, gel strength, viscosity, degree of
esterification, and setting characteristics.