A palatable, nutritionally complete vegetarian food for pet mammals, including a nutritionally complete, preferably low moisture, vegetarian kibble which incorporates a non-meat based flavour-enhancing additive. The additive includes a synergistic amount of hydrolyzed vegetable protein and xylose. The combination of these two ingredients provides an especially flavoursome character to the pet food. Also disclosed are the additive and a method of enhancing the flavour of such foods using the additive.