how does pectin work:

Pectin is a natural substance that can form a gel when heated in the presence of sugar and acid. The pectin molecules form a network of cross-links, which traps water molecules and create a solid gel.

The amount of pectin needed to form a gel depends on the type of fruit or vegetable, the ripeness of the fruit, and the acidity of the mixture. Fruits that are high in pectin, such as apples and citrus fruits, require less pectin to form a gel. Fruits that are low in pectin, such as strawberries and raspberries, require more pectin.

The acidity of the mixture also affects the ability of pectin to gel. Pectin gels best in acidic conditions. The acidity helps to break down the pectin molecules, making them more reactive and able to form cross-links.

Sugar also plays a role in the gelling of pectin. Sugar helps to attract the water molecules away from the pectin molecules, which causes the pectin molecules to come closer together and form cross-links. Sugar also helps to stabilize the gel, making it less likely to break down.