What does it mean when a recipe calls for coring a tomato?
The coring of tomatoes has a lot more to do with tradition than any sound foundations; the seeds in tomatoes can be bitter (and of course will ruin the texture of a smooth gazpacho) but the pulp surrounding them that is also discarded is rich in umami containing compounds:
http://www.guardian.co.uk/lifeandstyle/wordofmouth/2007/oct/23/hestonblumenthalstomatosauc

It proves something many cooks already knew or suspected - that the jelly around the pips of tomatoes contains most of the tomato's flavour. This is not so important for us home cooks - we tend to leave the seeds in the final dish we are preparing; but in the professional kitchen, the seeds are often discarded for the sake of appearance and presentation.
The title of Heston's paper that recently appeared in the Journal of Agricultural and Food Chemistry is Differences in Glutamic Acid and 5'- Ribonucleotide Contents between Flesh and Pulp of Tomatoes and the Relationship with Umami Taste (with co-authors Maria-Jose Oruna-Concha, Lisa Methven, Christopher Young and Donald S. Mottram from the University of Reading).
The paper's abstract cites the difference in taste we've all observed &quot;between the outer flesh and the inner pulp of tomatoes,&quot; and the fact that &quot;the pulp, which contains the seeds, had more umami taste.&quot; Umami, discovered by Ikeda in 1909, is the fifth taste, the meaty, broth-like or savoury taste that is now accepted as an addition to the traditional sweet, bitter, salty and sour gustatory sensations.
The paper shows that the inner pulp of the tomato contains up to 11 times the concentration of compounds associated with the umami taste as does the other flesh. This was determined experimentally, subjecting many different varieties of tomato to both chemical analysis and to sensory evaluation by a panel of human beings, who wore noseclips &quot;to evaluate taste attributes&quot; and took them off &quot;to assess all other attributes.&quot; And just to make sure they weren't prejudiced by visual clues (such as the deeper red of some tomatoes) all the tests were done under red lighting.