Raw desi tomatoes are much sour in taste than the mature red ones and thus, are ideal for cooking if you want to add a dash of sourness to your recipes without the use of lemons. Green tomatoes contain more proteins, food energy, calcium, Vitamins K-C-B1, choline and iron than their red counterparts. Unripe tomatoes are less juicy with firm and crunchy texture and tart flavor. This makes them suitable for dishes where you need to slice and fry tomatoes.