Place the sweet potato wedges in a large bowl, along with the parsnips and celeriac. Drizzle over a little olive oil.
Toast the coriander seeds in a dry frying pan until the aroma releases.
Remove from the heat, tip the seeds into a pestle and mortar, and gently crush.Add this to the vegetables along with the turmeric. Season and mix well. Lay the vegetables in a single layer on an oven tray. Roast for 20-25 minutes.
To cook the marinated pork, heat a large nonstick frying pan on a high heat. Brown each piece of pork on all sides and transfer to a baking tray. Cook for 12-15 minutes. Remove from the oven, cover with foil, and allow to rest for 10 minutes.
While the vegetables are cooking and the pork is resting, mix all the ingredients for the pineapple salsa and set aside.
Arrange the roast vegetables on a large board or platter. Thickly slice the pork and lay it on top. Serve the salsa to the side.