Heat the chicken stock in a pot to a gentle simmer. Heat the vegetable oil in a large pot over medium heat and saute the onion until translucent. Add the pearl barley to the pot and stir for one minute. Stir in the hot chicken stock, turmeric, lime juice, tomato paste, salt, and pepper. Bring the mixture to a boil, reduce heat to low, and simmer for 1 hour.