Pectin is used extensively in the food industry as a gelling agent. Not only is it used in jams and jellies, but also as a thickening agent and protein stabilizer. It is also added to diet sodas to improve mouthfeel.
Pectin is defined as low ester and high ester. In the US, the cut off between them is when 50% of the galacturonic acid groups are esterified. Low ester pectin requires minerals, typically calcium, to form gels.