Answer:
Sugar helps preserve the color, texture and flavor of the food. The sugar in jams and jellies helps the gel to form, and increases the flavor. When large amounts of sugar are used in a recipe, the sugar also acts as a preservative by inhibiting microbial activity; thus, recipes should not be modified or adapted.
Sugar as a preservative - by acting as a humectant (maintaining and stablishing the water content in foods), Sugar helps to prevent or slow the growth of bacteria, moulds and yeast in food like jam and preserves.
