Why would you think that, @RidingWindhorses? Bisto gravy powder contains Potato Starch, Salt, Wheat Starch, Colour (E150c), Yeast Powder (contains Barley), Onion Powder. E150C is caramel. What's so odd about any of that?
Don't know what goes into Oxo as I use Marigold bouillon powder, which contains Sea Salt, Hydrolysed Vegetable Protein (Soya, Maize), Potato Starch, Palm Oil (sustainable), Vegetables 8% (Parsnip, Onion, Leek, Carrot), Lactose (Milk), Parsley, Celery Seed, Turmeric, White Pepper, Garlic, Mace, Lovage, Nutmeg.