What you see: A hard, white area inside a tomato
What it is: Likely the result of problematic weather conditions on the farm
Eat or toss? You could eat it, but its hard texture might be unpleasant. The rest of the tomato, however, should be perfectly fine.
This poor tomato probably just got a bit too hot. There it was, in the field, gearing up to deploy lycopene, that magical pigment that makes tomatoes red and helps keep people healthy. The tomato was ready to develop a flavor just right for my salad, and a nice tender texture. But then things started to heat up on the farm.
Perhaps, as the sun beat down, the tomato plant's leaves weren't shading its fruit enough. Or maybe it was simply too darn hot. Whatever the cause, this tomato probably got warmer than 85 degrees. When a growing tomato gets that hot, its development stalls and you get those hard white areas.
Of course, this tomato isn’t totally a lost cause. See how the white hard area is only in one corner of that slice? That’s because this disorder commonly strikes what are called the “shoulders” of the tomato, the rounded areas on the top that are most likely to get that excessive sunlight.
While there are no safety concerns in eating this tomato, you probably won’t want to eat the white areas as their flavor, texture and nutrition won't be so great. But the red areas are still fine. You just get a little less salad tonight.
Steve Sargent - Professor and Extension Post-Harvest Specialist - University of Florida
Solving Tomato Problems - University of Illinois Extension
Help for the Home Gardener - Missouri Botanical Garden
Lycopene in tomatoes: Chemical and physical properties affected by food processing
Fried, white tomatoes?