Sesame seeds were created by the Self create Brahmana as the best food for the departed manes. Hence, gifts sesame seeds always please the departed manes greatly.
पितॄणां परमं भोज्यं तिलाः सृष्टाः स्वयम्भुवा। तिलदानेन वै तस्मात् पितृपक्षः प्रमोदते॥