Why while chewing starch in your mouth you feel sugar taste?

When you chew starch, an enzyme called salivary amylase in your saliva begins to break down the starch into simpler sugars like maltose. This enzymatic process starts as soon as the starch comes into contact with your saliva, releasing sugars that trigger sweet taste receptors on your tongue. This is why you may notice a sweet taste while chewing starchy foods like bread or potatoes.