Combine rice, beef, pork, onion, salt, monosodium glutamate, pepper and 3/4 cup tomatoes; mix well.
Steam cabbage leaves 3 minutes or until limp; drain.
Spoon meat mixture onto leaves; roll each leaf around meat turning ends under.
Place in large saucepan or dutch oven; pour remaining tomatoes over rolls.
Cover; simmer 30 minutes.
Remove rolls to warm platter.
Combine cornstarch and cold water; stir into liquid in saucepan.
Cook and stir over medium heat until mixture thickens and boils.
Serve with cabbage rolls.