Jump to content

Potato starch content


James Cain

Recommended Posts

Does anyone know of a source for starch breakdown (amylose, amylopectin, etc.) of different potato varieties, or even of staple starch plants in general? The closest I've come is the European Cultivated Potato Database, but they only comment on total starch content without breakdown, and there are no direct links to their sources.

 

 
This contributes a general expectation of amylose vs. amylopectin content based on cooking characteristics, but still no hard data!
Potato varieties, likewise, contain differing levels of amylose and amylopectin. Loosely classified into baking and boiling varieties, baking potatoes (which are comparable to long-grain rice) contain a higher proportion of amylose. On the other hand, boiling potatoes afford higher levels of the branched amylopectin.

 

James

Link to comment
Share on other sites

I'm actually mostly curious about starch and nutrient content for contribution to flavor and texture for different varieties, but I do have a practical interest as well. For example:
 

http://www.ncbi.nlm.nih.gov/pubmed/7840071

Effect of long-term consumption of amylose vs amylopectin starch on metabolic variables in human subjects.
Behall KM1, Howe JC.
Am J Clin Nutr. 1995 Feb;61(2):334-40.

Abstract
Long-term consumption of high-amylose starch on insulin and glucose response was investigated in 24 men: 10 control and 14 hyperinsulinemic (HI) subjects. Subjects consumed products made with standard (70% amylopectin, 30% amylose) or high-amylose (70% amylose, 30% amylopectin) cornstarch for two 14-wk periods in a crossover pattern. Starch products replaced usual starches in the self-selected diet for 10 wk followed by 4 wk of a controlled diet. After a starch-tolerance test with bread made from the starch consumed during that period, the insulin response curve area was significantly lower in all subjects after amylose consumption (P

 

http://www.ncbi.nlm.nih.gov/pubmed/9430599

Dietary amylose-amylopectin starch content affects glucose and lipid metabolism in adipocytes of normal and diabetic rats.
Kabir M1, Rizkalla SW, Champ M, Luo J, Boillot J, Bruzzo F, Slama G.
J Nutr. 1998 Jan;128(1):35-43.

Abstract
The aim of this study was to evaluate the effects of the chronic consumption of two starches, characterized by different glycemic indices and amylose-amylopectin content, on glucose metabolism in rat epididymal adipocytes. The two chosen starches were from mung bean (32% amylose) and cornstarch (0.5% amylose). The alpha-amylase digestibility was higher for the waxy cornstarch than that of the mung bean starch (60 +/- 4 vs. 45 +/- 3%, mean +/- SEM, respectively). The glycemic index of the waxy cornstarch diet (575 g starch /kg diet) was higher than that of the mung bean starch diet (107 +/- 7 vs. 67 +/- 5%, P

 

 

Link to comment
Share on other sites

James, I'm going to assume that you'd agree that the only reason to pay attention to the amylose vs. amylopectin content of potatoes is because of their relative effects on postprandial glycemia (and later, long-term metabolic (mal)adaptation to a diet chronically containing significant amounts of potatoes with such varying ratios). Therefore, another way to get at the same question is to ask instead, "what is known about the glycemic and/or insulin index or other metabolic effects of different potato varieties (or starchy vegetables)?" In fact, ISTM that this is arguably the better question to ask, since it takes "the whole package" of the potato into account (different fiber content and kind, or micronutrient content, or other starches) instead of just looking at one polysaccharide.
 
You probably already know about the conversion of amylopectin into amylose by cooking followed by chilling, but just in case (and because others will not):
 

Vinegar dressing and cold storage of potatoes lowers postprandial glycaemic and insulinaemic responses in healthy subjects.
A total of 13 healthy subjects volunteered for the study ... The study included four meals; freshly boiled potatoes, boiled and cold stored potatoes (8 degrees C, 24 h), boiled and cold stored potatoes (8 degrees C, 24 h) with addition of vinaigrette sauce (8 g olive oil and 28 g white vinegar (6% acetic acid)) and white wheat bread as reference. All meals contained 50 g available carbohydrates and were served as a breakfast in random order after an overnight fast. Capillary blood samples were collected at time intervals during 120 min ... Cold storage of boiled potatoes increased resistant starch (RS) content significantly from 3.3 to 5.2% (starch basis). [Glycemic index and insulin index] of cold potatoes added with vinegar (GI/II=96/128) were significantly reduced by 43 and 31%, respectively, compared with GI/II of freshly boiled potatoes (168/185). Furthermore, cold storage per se lowered II with 28% compared with the corresponding value for freshly boiled potatoes.

 

The glycaemic index of potatoes: the effect of variety, cooking method and maturity
Ten healthy volunteers were recruited ... Equal (50 g) carbohydrate portions of eight potato meals (three varieties [sebago, Desiree, Pontiac], four cooking methods ["using one variety, that is Pontiac: boiled, boiled and mashed, oven-baked and microwaved" -FULL], two states of maturity [mature vs  "new"; "Fresh new potatoes and canned new potatoes were tested because immature potatoes are known to contain starch with different amylose to amylopectin ratios" -FULL) and two reference white bread meals were fed in random order ...
 
GI values (mean +/- s.e.m.) ranged from 65+/-9 (canned new potatoes) to 10+/-15 101±15 (boiled Desiree potatoes) [sic!! PubMed abstract gives 10±15; full paper indicates 101±15!! -MR], glucose = 100. No significant difference was found among the three varieties of potato tested (P = 0.38) or among the four different cooking methods (P = 0.55).
 

gallery_727_15_37470.jpg

 
The GI values of the canned new potato and boiled Desiree potato were significantly different (P = 0.047). The average size of the tuber was found to correlate with the GI (r = 0.83, P<0.05).

 

 

Glycemic index of potatoes commonly consumed in North America.
Study 1: subjects consumed 200 g Russet or white potatoes that were either (a) precooked, refrigerated, and reheated (precooked) or ( B) cooked and consumed immediately (day-cooked). ... Study 1 comprised four men and six women, aged 20 to 44 ... Precooked Russet potatoes elicited lower area under the curve than day-cooked (P <.05), while precooking had no effect on boiled white potatoes.
 
Study 2: subjects consumed 50 g carbohydrate portions of white bread or potatoes (six different varieties and two different cooking methods). ... and Study 2 comprised 11 men and one woman, aged 18 to 50. ... The glycemic index values of potatoes varied significantly, depending on the variety and cooking method used (P =.003) ranging from intermediate (boiled red potatoes consumed cold: 56) to moderately high (roasted California white potatoes: 72; baked US Russet potatoes: 77) to high (instant mashed potatoes: 88; boiled red potatoes: 89).
 
[Data from Table 2:
Instant mashed potato 87.7 ±8.0xy
Baked Russet potato   76.5 ±8.7xyz
Roasted California white potato 72.3 ±8.2xyz
Baked Prince Edward Island white potato 72.8 ±4.5xyz
Boiled red potato (hot) 89.4 ±7.2x
Boiled red potato (cold) 56.2 ±5.3z
French fried potatoes 63.6 ±5.5yz

 

White Vegetables: Glycemia and Satiety
 
Summary of selected glycemic index and blood glucose responses by potato variety and preparation
[You can see the full table; much of the data comes from the studies cited above. Nearly all cases vary between 75 and 90. Sava and Desiree look like varieties to avoid; Estima and Nicola varieties look relatively promising, but are only reported as boiled and only in one report -MR]

 
There are also quite a few papers, many of them free in full-text, on pigmented "potatoes" (sweet potatoes etc):
 
http://benthamopen.com/tonutrj/artilces/V006/1TONUTRJ.pdf
http://www.hindawi.com/journals/jnme/2011/584832/
http://www.ncbi.nlm.nih.gov/pubmed/24577454
(Misleading title: "The glycemic index of pigmented potatoes is related to their polyphenol content" In fact, the GIs may have been statistically correlated with anthocyanidin content, but the magnitude of the difference is negligible).

Link to comment
Share on other sites

Thanks again, Michael, for such a great response!
 

James, I'm going to assume that you'd agree that the only reason to pay attention to the amylose vs. amylopectin content of potatoes is because of their relative effects on postprandial glycemia (and later, long-term metabolic (mal)adaptation to a diet chronically containing significant amounts of potatoes with such varying ratios).


You assume correctly. That is my "health" reason for the interest, but mainly it's an academic interest to see if there's a relationship between amylose, amylopectin, and other forms of starch (as you mention below) to their edible characterists such as baking performance, flavor, mouth-feel, etc. Of course there is, I just want to look at some hard data for potato varieties beyond the typical Russet, Yukon gold, and red (though it seems difficult to find this data too).

I'm not sure what you mean by your statement in parenthesis. Are you saying that a long-term diet based on potatoes would lead to metabolic dysfunction? I think any such conclusion would need more dietary context to be properly evaluated. I'm curious what you meant here.
 

Therefore, another way to get at the same question is to ask instead, "what is known about the glycemic and/or insulin index or other metabolic effects of different potato varieties (or starchy vegetables)?" In fact, ISTM that this is arguably the better question to ask, since it takes "the whole package" of the potato into account (different fiber content and kind, or micronutrient content, or other starches) instead of just looking at one polysaccharide.
 
You probably already know about the conversion of amylopectin into amylose by cooking followed by chilling, but just in case (and because others will not):


I am very knowledgeable of such things, and I do eat almost all of my potatoes and similar starches cold, partly for preference, convenience, and metabolic effects. I think your approach to answering my question is the best for health/metabolic application, and I practice it, but part of my brain wants to know the starch content of potato varieties to sate some odd curiosity.
 

[remaining post snipped]

Link to comment
Share on other sites

James, and all:
 

Thanks again, Michael, for such a great response!


You're welcome; glad you found it useful, tho' it sounds like you have a remaining interest in your original question as phrased.
 

 

James, I'm going to assume that you'd agree that the only reason to pay attention to the amylose vs. amylopectin content of potatoes is because of their relative effects on postprandial glycemia (and later, long-term metabolic (mal)adaptation to a diet chronically containing significant amounts of potatoes with such varying ratios).

 
I'm not sure what you mean by your statement in parenthesis. Are you saying that a long-term diet based on potatoes would lead to metabolic dysfunction? I think any such conclusion would need more dietary context to be properly evaluated. I'm curious what you meant here.

I mean that (as I'm again sure you're aware) it's pretty well-established that eating a high-glycemic-index and (most especially) high-glycemic-load diet puts one at elevated risk of metabolic disease and possibly some cancers; potatoes being a pretty high-GI and (if incorporated in any but small amounts and as part of an overall low GL diet) high-GL food, regular consumption as part of a "normal" diet is likely to lead to ill-health (though as reviewed, there are several strategies available to blunt this risk over and above just minimizing consumption).

Link to comment
Share on other sites

James, and all:

 

You're welcome; glad you found it useful, tho' it sounds like you have a remaining interest in your original question as phrased.

 

I mean that (as I'm again sure you're aware) it's pretty well-established that eating a high-glycemic-index and (most especially) high-glycemic-load diet puts one at elevated risk of metabolic disease and possibly some cancers; potatoes being a pretty high-GI and (if incorporated in any but small amounts and as part of an overall low GL diet) high-GL food, regular consumption as part of a "normal" diet is likely to lead to ill-health (though as reviewed, there are several strategies available to blunt this risk over and above just minimizing consumption).

 

I figured that's where you were going with this, and I largely agree. It's really difficult to give blanket advice about this because I doubt many people eat just potatoes as a meal. As you know, adding in a pile of veggies, beans, and/or fat (or animal products) could substantially lower the meal's GI/GL, even if potatoes provide the bulk of the calories. Even then, my personal experience and research suggest that consistent consumption a whole-food, low-fat, high-carb diet usually improves insulin sensitivity and reduces HbA1c and insulin. Then again, these dietary interventions almost always lead to weight loss as well, so that could largely explain the improved glucose tolerance.

 

This isn't a simple issue so I won't make generalized conclusions, but in defense of the potato, for me eating a lot of potatoes, veggies, and beans with a few nuts and seeds, all while either maintaining my weight or being hypocaloric, results in my lowest fasting and postprandial blood glucose readings. I also find potatoes to be fairly nutrient dense, compared to standard diet fare that most people consume. Plus as you say it's a backpack problem--combined with some veggies (especially something like broccoli), almost all micronutrient and protein needs are met at around 1200 kcal (2 lbs baked Russet potato, 875 kcal, and 2 lbs boiled broccoli, 315 kcal).  Add a bit of flaxseed and additional foods to fill in personal preferences or nutrient needs and you've got a very simple and nutritionally adequate diet that may very well be metabolically healthy (or tolerable) for most people. 

 

I think potatoes can be a valuable addition for many newcomers to a CR diet, or for those who find a more strict CR diet too restrictive. It may not be a perfect food choice, but it's certainly leaning farther towards the "healthy acceptable" side of things. I also tend to advocate general diet improvements and mild CR for the general population. Established or more severe CR practitioners would probably be better off without potatoes as a diet staple.

 

While not definitive, I think Stephan Guyenet's post The Glycemic Index: A Critical Evaluation is a worthwhile read, at least as a collection of relevant research.

 

 

P.S., It seems that when I respond to posts the forum software automatically clips the sub-quotes. As en example, the above quote is all that was included when trying to quote the whole message.

Link to comment
Share on other sites

  • 4 weeks later...

 

James, and all:

 

You're welcome ...

 

 

P.S., It seems that when I respond to posts the forum software automatically clips the sub-quotes. As en example, the above quote is all that was included when trying to quote the whole message.

 

Sub-quotes have been enabled (see example above) - it was a forum setting issue.

Link to comment
Share on other sites

 

 

James, and all:

 

You're welcome ...

 

 

P.S., It seems that when I respond to posts the forum software automatically clips the sub-quotes. As en example, the above quote is all that was included when trying to quote the whole message.

 

Sub-quotes have been enabled (see example above) - it was a forum setting issue.

 

 

So they are.

 

Thanks, Tim!

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...