If something is sulphurised, it means that it has been treated with sulphur or a sulphur compound.
Sulphurised things are often preserved or protected in some way.
Examples:
The dried fruits are sulphurised to keep them fresh.
We sulphurised the wine to preserve it.
The sulphurised rubber has a distinct smell.
I don't like the taste of sulphurised food.
The sulphurised paper will last a long time.
She sulphurised the fabric to protect it from insects.