Campbell's Chunky Cheese Tortellini with Chicken and Vegetables

Ingredients: Water, carrots, celery, cheese tortellini (dough mixture(enriched durum flour(Durum flour, niacin, ferrous sulfate, thiamin mononitrate, riboflavin), water, eggs), filling (ricotta cheese (whey, pasteurized whole milk, skim milk, salt), Parmesan cheese (part skim milk, cheese culture, salt), bread crumbs (bleached wheat flour), dehydrated parsley, salt, spices), potatoes, chicken meat, diced tomatoes, zuccini, Italian green beans, potato starch, contians less than 2% onion, salt, chicken flavor, yeast extract, onion powder, monosodium glutamate, corn syrup solids, vegetable oil, spice extract, dehydrated garlic, chicken fat, modified food starch, soy protein isolate, sodium phosphates, chicken broth powder, spice, chicken flavor (chicken stock, chicken powder, chicken fat), beta carotene, flavor,citric acid.

Why use ferrous sulfatesometimes and iron others?

What type of modified food starch?

What is the function of beta carotene?