Adding salt while roasting tomatoes in an oven serves several purposes:
Enhanced Flavor: Salt is a fundamental seasoning that enhances the natural flavors of ingredients. When added to tomatoes before roasting, it helps intensify their taste, making them more savory and delicious.
Moisture Extraction: Salt has hygroscopic properties, meaning it draws out moisture from the tomatoes. By sprinkling salt on the tomatoes before roasting, some of their moisture is released, which concentrates the flavors and contributes to the caramelization process during roasting. This results in a more concentrated and rich tomato flavor.
Improved Texture: The moisture extraction brought about by salt can also lead to a better texture in the roasted tomatoes. As excess moisture evaporates during roasting, the tomatoes become less watery and more tender, with a desirable chewiness.
Preservation: Salt is a natural preservative. Although roasting tomatoes will remove some of their moisture content, adding salt can help preserve them for a slightly longer period, especially if you plan to store them or use them in dishes later.
Browning and Maillard Reaction: Salt can help with the Maillard reaction, a chemical process responsible for browning and creating complex flavors during roasting. When the sugars and amino acids in the tomatoes react with heat, they undergo this Maillard reaction, which adds depth and complexity to the roasted tomato flavor.
When roasting tomatoes, it's best to use a moderate amount of salt, allowing you to control the seasoning and avoid oversalting the dish. Additionally, you can complement the salt with other seasonings like pepper, herbs, or olive oil to further enhance the overall flavor profile of the roasted tomatoes.