Resistant Starch

I listened to a radio programme this week that said

reheating carb-heavy foods actually boosts the resistant starch in them. Resistant starch is a healthy carb that can benefit your gut, reduce blood sugar spikes and lower your cancer risk.



It talked about reheating the previous days left over pasta. As I measure pasta I never have any leftover, so would have to cook pasta in advance. Resistant starch is fibre and thus (I take it) filling but will pass through one without leaving many calories

I have a number of questions I want to ask the experts on this forum
1) how long before reheating does one have to cook the pasta (or potatoes or rice), i.e. how long do the carbs need to be cool?
2) are all the 'bad' carbs turned into resistant starch?
3) what are the dangers of cooking, keeping and reheating pasta, potatoes or rice? (I recall warnings about reheating left over rice)

The programme is here
https://www.bbc.co.uk/programmes/m001rq3z

This is a good (and practical) summary: https://hopkinsdiabetesinfo.org/what-is ... nt-starch/

The science is here (but it's long): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3823506/
The relevant part to your question is:

Type III resistant starch (RSIII) is retrograded amylose and starch (21–23). Because amylose molecules have linear structures, they have a great tendency to form double helices, particularly near refrigeration temperatures (4–5°C) and with adequate moisture content. Retrograded amylose has high gelatinization temperatures, up to 170°C, and cannot be dissociated by cooking. The gelatinization temperature of retrograded amylose, however, decreases with shortening of the amylose chain length. After starchy foods are stored, particularly in a refrigerator, amylose molecules and long branch chains of amylopectin form double helices and lose their water-binding capacity. The double helices of starch molecules do not fit into the enzymatic binding site of amylase, thus they cannot be hydrolyzed by this enzyme.

I would take it from that that the starch has to cool completely in order to twist up. So, the issue is not how long the cooked food rests but rather that it reach a cool temp.

i]reheating carb-heavy foods actually boosts the resistant starch in them. Resistant starch is a healthy carb that can benefit your gut, reduce blood sugar spikes and lower your cancer risk. [/i

In other words, resistant starch (helical amylose and amylopectin) is harder to digest (digestion is what it's "resistant" to).

This process probably explains the change in texture of leftover pasta that's been refrigerated and then reheated.

-Paul W.

Thanks chaps, but my three questions are still unanswered. The first link says to

Try cooking rice, potatoes, beans, and pasta a day in advance and cool in the refrigerator overnight.

So on Saturday I boiled Sunday's potatoes, let them cool and put them in the fridge.

Sunday about 16:00 I took them out the fridge to bring them up to room temperature, then at 17:30 I put them in a baking tray with some oil and put them in a hot oven to make roasties.

They tasted fine, no different from usual. Eight hours later I was wakened by a pain in my stomach, lots of wind, and typing this on Tuesday I am still uncomfortable.

The symptoms remind me of the effects I got after eating Jerusalem Artichokes, though less severe.

Tonight I am having pasta. I was going to cook that yesterday and put it in the fridge. I did not. I'm giving resistant starch a miss.

Mrs M was not affected, neither was she after the Jerusalem Artichokes.

Saliva and the digestive enzymes released in the small intestines break up common polysaccharides such as sucrose (table sugar) and starch (glucose polymer, aka amylose annd amylopectin) into simple sugars that are absorbed by the gut. Dried beans and Jerusalem artichokes contain high levels of polysaccharides for which the human gut doesn't have enzymes to break them down. So they don't get absorbed and instead they're fed upon by bacteria in the gut, which convert them to carbon dioxide gas. This disturbance of normal digestion results in wind and other indigestion symptoms. This is why Indian dal (dried legume) dishes almost always have ginger and other carminative spices in them. They suppress bacterial activity and thus reduce the gas problem.

I was wondering if resistant starch might have similar effects.

Lactose intolerance is another example of this phenomenon. The enzyme that splits lactose (milk sugar) into glucose and galactose is secreted by the gut of human infants, but most humans stop producing lactase once they are weaned. Bacterial action on the lactose results in gastric distress. Only a few ethnic groups (Europeans and Indians) where animal milk is an important part of the culture have evolved to continue to produce lactase as adults. Most people can't tolerate milk products as adults. This is why the cuisine of China--a place where they eat almost anything--is devoid of dishes containing milk or cheese.

-Paul W.

I have a number of questions I want to ask the experts on this forum
1) how long before reheating does one have to cook the pasta (or potatoes or rice), i.e. how long do the carbs need to be cool?

27.244 minutes. Not a second more.

2) are all the 'bad' carbs turned into resistant starch?

Unrepentant starches become resistant starches; the more compliant kind simply shuffle off to polysaccharide heaven like good little molecules should.

3) what are the dangers of cooking, keeping and reheating pasta, potatoes or rice? (I recall warnings about reheating left over rice)

Tends to glue your tongue into your cheek.

[Jenise]

I am SOOOO not the science type and can barely understand a lot of what you guys are talking about. I will say this, though: I think reheated rice is the best rice. I love it when it gets stickier, chewier after the retained moisture evaporates out, and I deliberately cook rice early in the day in order to achieve that result. Never had any issue with it.

I am SOOOO not the science type and can barely understand a lot of what you guys are talking about. I will say this, though: I think reheated rice is the best rice. I love it when it gets stickier, chewier after the retained moisture evaporates out, and I deliberately cook rice early in the day in order to achieve that result. Never had any issue with it.

Jenise, I thought I was the only one who did this. I do not like to cook in the evening (cocktail hour) and time to relax and let the days' battles go... I have always done food prep in the mornings, and yes, even cooking rice or any other grain. Yesterday, I made a risotto and turned off the heat before it was done. That evening the farro was perfect, still a little bite to it just the way I like it. I also cook my beans early in the day, as well and let them sit in the beautiful pot liquor. Same with pastas, I like it better after it has soaked up some of the sauce...

Rice!? I have eaten rice practically every day of my life (Louisiana native). I have reheated rice that has sat out on the stove over night; rice that has been refrigerated for up to 5 days; and rice that has been frozen for up to a month. The texture in the way that all three are handled is different, more than palatable and often desirable. The smell and texture of rice that has begun to "spoil" is unmistakable - at least to me. I have never had a problem in my gut from rice. I don't understand much about this starchy benefit that is discussed about this article. But once I saw the word "rice" it piqued my interest. Huh!

I was recently the recipient of an all-but-completed risotto from my upstairs neighbor (who is an excellent cook). All I had to do was finish the last few ladles of hot broth... and the texture was perfect. Happy to reheat rice like that!