what is a starch
Best Answer: Starch is a complex carbohydrate which is insoluble in water; it is used by plants as a way to store excess glucose.Starch is by far the most important of the polysaccharides.It constitutes more than half the carbohydrates even in affluent diets, and much more in poorer diets.tarch (CAS# 9005-25-8) is a complex carbohydrate which is insoluble in water; it is used by plants as a way to store excess glucose. Starch is by far the most important of the polysaccharides.