What you’re seeing is usually a specular reflection, often called a highlight or glare. It happens when light reflects from a relatively smooth surface in a more directional way, so some of that reflected light goes straight into the camera.

Most real subjects produce both:

• diffuse reflection: scattered light from rougher surface texture
• specular reflection: the shinier, brighter reflection from smoother areas

That’s why even a fruit shot in soft light can still show a bright patch.

To reduce it, you can:

• change the light position so the reflection is directed away from the camera
• change your camera angle
• use a polarizing filter, which can often reduce specular reflections because they are often partially polarized

Also, some highlight is normal and can help the subject look three-dimensional and realistic. The goal is often not to remove it completely, but to control its strength and placement.