One cup of mung bean sprouts contains 26 calories. Sprouted mung beans are baby mung bean plants. Because mung bean sprouts are so small, they contain a concentrated amount of key vitamins and minerals such as iron, potassium, folate and vitamin C. They are also a good source of protein.prouted mung beans don't contain as much protein as animal sources such as meat, fish, eggs, milk and cheese, but they do supply a small amount. One cup of sprouted and cooked mung beans provides 2.5 grams of protein toward your daily goal of 8 grams for every 20 pounds that you weigh.