The correct answer is 0. 5 to 1. 0. Pectin is a polysaccharide starch that is used as a thickener in cooking and baking. It is found in the cell wall of vegetables and fruits. For making good jelly, 0. 5 to 1. 0 percent of pectin is used. Below this percentage range, jelly cant be set and above this, the jelly gets very hard and tough. Additional Information Following are the essential constituents and proportions of a Jelly:1. Sugar - 60 to 65%2. Fruit acid - 1%3. Pectin - 0. 5 to 1%4. Water - 33 to 38%