Kick-start your day on a healthy note with the Prepacked Portobello Mushroom. This meaty-textured mushroom contains copper for keeping your immune system and blood vessels healthy. It also contains potassium for keeping your blood pressure in control and phosphorus for strong bones and red blood cells. Since they contain essential nutrients and low calories, these intense-flavored mushrooms make for a nutritious addition to your diet. Kick-start your day on a healthy note with the Prepacked Portobello Mushroom. This meaty-textured mushroom contains copper for keeping your immune system and blood vessels healthy. It also contains potassium for keeping your blood pressure in control and phosphorus for strong bones and red blood cells. Since they contain essential nutrients and low calories, these intense-flavored mushrooms make for a nutritious addition to your diet.