Potatoes

[jameshallam]

Hi all,

I have a query about the amount of carbs in potatoes and 'dervied' foods.
According to "carbs and cals" the amount of carbs in potatoes is:

(grams carbs / total grams / %)

Jacket : 20g / 95g / 21%
Mash: 20g / 120g / 17%
New: 10g / 65g / 15%
Croquette: 5g / 22g / 23%
Roesti: 20g / 80g / 25%
Roast: 10g / 38g / 26%
Wedges: 10g / 55g / 18%
Oven (or deep fried) Chips: 10g / 33g / 30%
Cassava Chips (Chunky chips): 30g/45g / 67%

So a potato varies in the amount of carbs somewhere between 15% and 67% - just on how it is cooked... Can anyone explain this? I figure it can't be to do with what is added when cooking (e.g. you add butter & milk to mash) because you don't add enough to cause such a stark difference.

My current theory has something to do with the water level in the food (as during cooking this water level will change) because water will affect the total mass but not the mass of the carbs?

Thoughts anyone?

 

[noblehead]

You've sort of answered the question yourself James. Much will also depend on if the skins are eaten or removed, coatings used and cooking method, how they are prepared and cooked will also determine how fast they will digest and effect blood glucose, for further info check out the glycemic index.

Nigel

 

[shedges]

The cooking process does affect the starches and sugars remaining in the potatoes. And as you say, whether they are cooked dry or in water will make a difference too.

The biggest change I experience is oven roasting root vegetables. The Glycemic Index is completely thrown out, with the value increasing significantly... the vegetables simply taste sweeter too!

 

[hanadr]

Different varieties of potato also have differing amounts of starch. Vivaldi is meant to be particularly low.
As a general rule, new pots have less than old ones and "floury" varieties more than "waxy"
Hana
in your own case, you just have to test to find the effect they have. Maake a note of which cvariety suits you best.

 

[phoenix]

The cooking process does affect the starches and sugars remaining in the potatoes. And as you say, whether they are cooked dry or in water will make a difference too.

The biggest change I experience is oven roasting root vegetables. The Glycemic Index is completely thrown out, with the value increasing significantly... the vegetables simply taste sweeter too

I agree but It isn't the concept of the GI that is a problem, its relying on lists. Learning a bit about what affects the GI of a food makes it easier to make better choices.
A yam boiled has a GI of about 35, when roasted its about 75-80. Very fast.
On top of this some recent research seems to show that you may be actually digesting more carbs than if it were cooked in a different way
Research on animals and on some patients who have had an illeostomy seems to demonstrate that protein and carbs (no research has been done on fat) are not 100% available when food is raw. A percentage (varies according to food) is not absorbed for energy and passes into the large intestine, where bacteria but not 'our body' uses it for energy.

When starches are cooked or otherwise processed, the raw starch molecules “open up” so that sugars can be easily broken off and then digested. With foods that have undergone pounding, long cooking or high temperatures, its as if the first stages of digestion the chewing and the breaking down by enzymes have already been partly done ..These foods are more readilly absorbed by the body than those that have undergone less processing or are only cooked at low temperatures.
As roasting is done at high temps (and often for longer) than boiling or steaming the carbs from these veg will be more easily absorbed. The recent research suggests that not only are they more quickly and easily absorbed but less is left to escape to the large intestine; in effect you are aborbing more of it.

The energetic significance of cooking Rachel N. Carmody, Richard W. Wrangham*2009
http://www.anthro.utah.edu/PDFs/Carmody ... gHumEv.pdf


There is an illustrated lecture by Wrangham that has a section about the effect of cooking on food but it is only part of the lecture which is about the theory that cooking made us human
http://vimeo.com/10763241

 

[shedges]

I agree with Phoenix - that's what I wanted to say, but didn't have time to research or link.

Nice one 8)