Cooking chutney is a slow process over medium-low heat. This means the sugar will first melt then combine with the fruit juices and eventually it will cook down. As the sugar cook and thickens, it will get that syrup consistency. If you cook the chutney on high heat quickly it will not go through the natural process of cooking and thickening. So, cook on medium-low, stirring often, and watch the magic take place.