I think that if you making jam without 'real' sugar at home gives rise to a product that soon develops mould. High sugar levels act as a natural preservative. My other half tends to make 'jellies' (Crab Apples, Red Currant, Gooseberry etc). You can then use an artificial sweetner of choice. Also, if you cook the fruits and sweetner without removing skins/pips/seeds you can often get away without adding Pectin with the debris being left behind in the 'jeelybag' when straining.