They were cultivating sweet potatoes in Central and South America for about 7–8000 years before Columbus arrived. He thought they looked like yams and tasted like chestnuts, and shipped them back to Spain along with chillies and chocolate. Like ducks to water they took to local conditions and thrived in the Mediterranean climate.
This was just the beginning of their global conquest – they are now grown in more developing countries than any other root crop. They have a big advantage over regular potatoes – their skin does not develop green patches. They are easy to prepare – peel or scrub and roast, boil, steam, mash, add to stir-fries or use in place of pumpkin in desserts (although they are not as sweet and are much starchier, so they will thicken a dish more).
Sweet potatoes come in a variety of colours, shapes and sizes. It’s the orange-fleshed sweet potato that we like to roast and use in recipes for its colour and sweet flavour. It also has a moderate GI value (65). The white-fleshed sweet potatoes that have been tested have a high GI (75).
When shopping, look for small to medium even toned sweet potatoes with firm skin that are free from blemishes, cracks and soft spots. They should be plump in the middle and tapered ends. Buying similar sized ones makes it easier to get cooking times right. They are good keepers. Store them in a cool, dark, well ventilated place for up to 2 weeks. Don’t store sweet potatoes in the fridge – that will promote softening, sprouting and can cause them to develop a permanently hard centre.
Source: The Good Carbs Cookbook (by Alan Barclay, Kate McGhie and Philippa Sandall) published by Murdoch Books