The one fact that everyone seems to know about parsnips is that they taste better after they have had a frost through them. The starches turn to sugar, making them sweeter, that's what all the web pages say. But why? With sweetcorn, it's the opposite. You have to run to the pan of boiling water to throw them in before the sugars turn to starch. Vegetables are contrary things.
According to this website (which describes the parsnip as "slightly mucilagenous" - not a great marketing slogan), at low temperatures starches are converted to sugars. This has been known for quite some time, as this textbook from 1867 mentions the change.
This paper from the 1940s looks at how these changes occur in potatoes, but the physiological reason behind the changes from starch to sugar is best explained by this article. Again it looks at potatoes but the reason must be the same - the change of starch to sugar lowers the freezing point of the fluid in the plant cells. This makes the vegetable cells less likely to be damaged by the cold weather (if you want to do an experiment, water with sugar or salt added to it will freeze at a lower temeprature than pure water).
So - great for the plant as it can cope with lower temperatures without its precious storage organ being damaged over winter, and great for us as we get a sweet, tasty veg for our Christmas dinner table.
Just don't try and make parsnip cake.
12 comments:
My dear hm
You may recall my recent obsession with parsnips.
Although I've yet to grow them, & had never cooked them, I found lovely ones at the market - just the right size...not too big..nor small, and did, indeed, roast them with potatoes for Thanksgiving dinner. They added a sweet tangy flavor to the dish, to my delight.
Leaning on T to plant them at his allotment next year.
(I don't know if the ones I purchased were locally grown. ) You grow them from seed, yes? Will have to find a source and plant them later in the season.
Haven't read all your article links, but do appreciate your research! Happy xmas, Happy!
I give over a quarter of my vegetable beds to parsnips, just for Christmas. Love them! There is nothing like taking them out of the ground, cleaning and then roasting, sweet as you like. Glad there is some science behind the whole frost thing.
Having said that, most of my parsnips last year looked pretty bizarre.
Wishing that I had made an effort to grow some this year - one of my favourite veg :)
I associate you (well, your posts) with parsnips. Is there are Parsnip Marketing Board?
Lucy
I have never eaten a parsnip, nor seen one on offer at any table to which I've been invited. It's not an Italian thing, and it must not be an American thing either. After your glowing description, I'd be willing to give one a try.
interesting...I was just pondering parsnips today. Got some free seed last year that I never used.
Btw, I think a red top hat is totally bonkers, but you should get one nonetheless, so i voted yes.
I didn't know that about parsnips!! This is the time of year when the Bedsock wants me to make curry parsnip soup - it is fab and great for winter walks but needs the frostbitten parsnips for sweetness.
You really must have the red hat - my hats are used as ornaments, well they were until Spook got hold of my Australian one. :(
Like MMD, we have never even once seen a parsnip cooked and offered. Not at a restaurant or someone's house. They are offered for sale at the grocer's, so someone must be buying them. Roasting is best, would you say? Maybe we'll give them a go. Butter and salt added? The mucus connection is a bit offputting however. :-)
Frances
Can't stand parsnips - never have. However, I do like to know lots of facts so I am grateful for this post - it's a bit like Melvyn Bragg's In Our Time, but a lot more accessible...
Lets hope it thaws ebough to dig them out of the ground for Christmas.
Bay Area Tendrils - good luck with your parsnips. Yes, I grow them from seed (need fresh seed every year).
GA - they may be odd shaped, but I bet they taste wonderful.
Anna - get yourself some see for 2010!
Lucy, if there is then I demand some royalties.
MMD - worth a try, at least once.
Frances - yes, roasted in oil, the same way you would roast potatoes but for a little less time. The mucus thin sounds worse than it is - when you peel them, they just feel slightly mre slippery than a peeled potato would.
Wendy - thanks for your yes vote!
Arabella - mmmm, curried parsnip soup. Lovely. Good idea about making the hat an ornament, then it needs no justificatino apart from looking good.
Dawn, that is the first (and possibly last) time I have been compared to Melvyn Bragg.
Joanne - a very good, and slightly concerning, point. We need to dig them up on Weds, as we are off down to my father's on 24th. The digging may be tough.
Hello and thank you for visiting my blog and leaving a comment. Now that I have found yours I will add it to my 'reading blogs' on my side- bar. I am glad I read your comment about new seeds every year for parsnips, as someone recently told me that so I will get some new ones for next year. I hope you try my Parsnip and Orange recipe, it's lovely but my husband found it a bit sweet for his taste.
Have a lovely Christmas and a fab New Year. :)
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