Trimming the top and coring a bell pepper removes the stem, seeds, and inner membranes, which can be bitter and tough, improving the pepper's flavor and texture for cooking or eating raw.
Removing the top and core of a bell pepper serves several important purposes. First, the stem is generally tough and not palatable. Second, the seeds are often slightly bitter and can detract from the overall flavor of the pepper, especially when eaten raw. Third, the white inner membranes, particularly around the core, can also have a bitter taste and a tougher texture than the rest of the pepper's flesh. By removing these parts, you are left with the sweetest and most tender part of the pepper. This is especially important when using bell peppers in salads, salsas, or other dishes where the raw flavor is prominent. When cooking, removing the core also creates a cavity that can be easily stuffed with fillings like rice, meat, or cheese.
To easily remove the core, try pushing the stem into the pepper, then twisting and pulling it out. This often removes the core and most of the seeds in one motion, minimizing mess and waste.