Gelatin is a cousin to protien and comes from disolviing collagen that is found in cartilage and bone tissue. Agar is a fiber, much like qsillium husks, that is derived from seaweed. Both absorb and stabilize water in a "plastic" state (plastic being something between a liquid and solid). Both have healthful benefits for the body. The fiber helps absorb choleserol, helps maintain a healthy colon, helps elliminate insulin swings by slowing the rate of sugar absorpption into the blood. Collagen aids in cell growth and maintainance, helps skin and hair strength.
Both are very good products with little or no adverse effects to the body.
the jelled property of a good stock when cooled is caused by the collagen dissolved in the liquid. The same thing happens with gellitin products such as Jello.
The jelled consitancy of jams and jellies is a function of pectin, a fruit fiber found in apple skins, and other fruits.
Seeeeeeya; Goodweed of the North