Learn Turkish: Antrenör hamur işini sınırladığı halde gizlice pasta yemiş. - Even though the coach restricted pastry, he secretly ate cake.

This is the structure you are learning in this lesson! It starts with the verb sınırlamak (to restrict). We drop the -mak and add the participle -dık. Since it is his restriction (the coach's), we add the 3rd person possessive -ı. This softens the k to ğ, giving us sınırladığı. Finally, we add halde (even though / in the state of). Literally, it translates to "in the state of his restricting."

Why is there an -ni at the end of hamur işini?

Hamur işi (pastry / baked goods) is a noun compound made of hamur (dough) and işi (its work). Because it already ends in a possessive suffix (-i), when we need to add the accusative case suffix (-i) to show it is the direct object of the verb, we must use the buffer letter -n- instead of -y-. So it becomes hamur işi + n + i.

Why does hamur işi get an accusative ending, but pasta doesn't?

We use the accusative case (hamur işini) because the coach restricted that specific category of food. However, pasta (cake) is just a general, non-specific object here—he just "ate cake" or "ate a cake." In Turkish, non-specific direct objects don't take any case endings and generally sit right next to the verb.