Are there alternatives for citric acid, pectin and inverted sugar?

Citric acid can be replaced by malic acid or citrus juice.

There is no direct substitute for pectin, but you can buy apple pectin in stores. Apple pectin is a powder that can be added to fruit mixtures to help them gel.

Inverted sugar is used in some recipes because it helps to prevent crystallization and make the product softer. It is a unique ingredient, but it is not essential to a recipe.