Hello Joanna, we use bitter orange juice in soups made with pulses. I will give you a recipe that my mother and aunt used. The soups were eaten during the fasting periods in winter as they were vegan vegetarians in accordance with their G. Orthodox religion.
Recipe. 1/2 liter cold water, I cup of split peas, 1/4 cup round rice, 1medium size onion chopped to small pieces, 100 ml olive oil, juice of a bitter orange, juice of half lemon, salt pepper
Put water and split peas on heat. Bring to boil, remove the froth that first appears and then add rice. Cook on gentle heat until rice and peas are soft. Cook chopped onion in the olive oil and when onions are soft add to the cooked peas and rice. Put all the mixture in the blender and add some of the juice of b. Orange and lemon. Check for flavour after you seasoned with salt n pepper. Add more b. Orange or lemon according to your taste buds. Nota bene you can add more water if you like your soup thin or boil longer to reduce water content which I am sure you already know.