The minimum TSS of tomato sauce must be

The minimum TSS of tomato sauce must be 30%.
Total dissolved solids (TSS) are an important parameter of fruit quality. TSS states the amounts of soluble solids in liquid. TSS value affects the taste of the fruit because it can indicate the level of sweetness of the fruit.
Tomato sauce has a TSS of 25 - 30%, while ketchup has a consistency of 28 - 30%. This is because ketchup contains more spices and seasonings than the sauce.