It depends on the type of ingredients you are using in your marinade. If you are making a Tikka-style marinade, you can add more fats to the mixture. And it should do the job for you. For vegetarians, you can use some vegetables like Potatoes and Cauliflower. These veggies should help in balancing the sour taste. On the other hand, if you are making a basic marinade without yogurt, you can also add Baking Soda or Baking Powder to it. But as I mentioned earlier in the guide, you need to keep an eye on the quantity of soda you add to your preparation. Otherwise, you may end up changing the taste of your preparation. And with too much Baking Soda, you can't expect the authentic taste for your dish.