I have a recipe for kumquat marmalade, it calls for 2 parts fruits, 1 part sugar and 1 part water. Before boiling the liquid it states that one should macerate the fruit in de sugar water first. How does this maceration help?
Macerating breaks down the fruit and extracts the juices. Especially when making jam, it can expedite the process, allowing you to prep the fruit a day in advance. While some recipes say to macerate for several hours, letting it sit overnight can produce better results, particularly when using dried fruits.
Maceration is the "magic" (really science) of applied osmotic pressure. The sugar mixture will draw fluid out of the fruit (indeed, many maceration steps are done by mixing the dry sugar with the fruit, rather than by placing the fruit in sugar-water - there is soon fluid, and the osmotic pressure is considerably higher since the concentration of sugar is higher. If water is needed, it would be added after maceration, in those recipes.)