Gelatin is a remarkably versatile ingredient, but many diners find it problematic for religious or ethical reasons. It's made from the hides, hooves and bones of cattle and hogs, the "none of the above" that accumulates in slaughterhouses when everything else is removed. Vegetable gelling agents such as pectin can take its place, though this fruit-derived thickener is comparatively limited in its uses.
Jiggly and Sweet
Either gelatin or pectin can set fruit juices to a soft, delicate texture or one that's relatively firm, but they work in different ways. Gelatin can set almost any liquid, as long as it's first heated and dissolved. Pectin is more finicky, because its carbohydrate molecules need help to form a bond. They need a great deal of sugar, which binds up most of the water molecules, and then a healthy splash of acidity to reverse the electrical charge that ordinarily makes them repel each other. That's why many recipes call for added lemon juice.
If you'd like to experiment with pectin in gels, fruit juices -- whether fresh, frozen or canned -- provide the best vehicle. They're still palatable when heavily sweetened, and you can keep them from cloying by using a blend of naturally tart juices or adding lemon. Work with a jelly-making recipe and scale down the quantities to a reasonable level, increasing the amount of pectin as needed until you achieve a good gel. For a firmer or less-sweetened gel, use a "low-sugar" variety, which is a more concentrated form of regular pectin.