Yellow plantains are characterized by the age of the fruit. They are essentially at the middle stage of the fruit's maturity. Yellow plantains have a slightly firm and starchy texture, mild, almost insipid flavor and lower sugar content. Yellow plantains are sweeter than green ones but they're still mostly prepared in savory ways. In particular, plantains are decent sources of magnesium, potassium (more than bananas), vitamin A, and vitamin K. They also supply some vitamin C and B vitamins, such as thiamin and riboflavin.