From literature performing starch extraction with water can achieve about 90% starch whereas performing it with enzymes changes the starch into glucose.
If your aim is to extract the starch in its native polysaccharide form then you must go for water mediated extraction. Boiling the sample at moderate temperature (50-70) may result in the release of starch from it. Although the amount of extracted starch will significantly vary with the sample type and its morphological constitution.