I'm thinking you need to at least use a light syrup for fruit. Otherwise the sugars from the fruit will leech into the canning liquid and the fruit will not retain its natural sweetness. If you need to have less sugar in the finished product, rinse it when taking it out of the jar. It's been several years since I have done food preservation but I'm thinking that used to be the recommendation for either canning or freezing fruit. Do they still recommend a product such as Fruit Fresh to prevent browning, esp of peaches?