Talk:Starch/Archive 1

Clean Up?
I think this article needs a little polishing. One thing that would help is to describe and show an image of the common 1-4 glucose bonding to actually SHOW what starch is in amylose form, and the difference between that and amylopectin.

I notice that the article states that starch can be dissolved in hot water. It might be helpful to provide an explain why, when cooking, starch must be dissolved in COLD water, and then the COLD, dissolved mixture is slowly added to a hot mixture (gravy for example) to avoid a big, irreversible clump.

How do you make starch then?

You don't have to make starch. It's naturally found in vegetables and plants, so you just have to extract it from the other stuff the plant is made of. The article How to make starch from frosted potatoes has apparently been deleted -- could someone else write about the process? GUllman 23:25, 21 Sep 2004 (UTC) Biosphre


 * You can buy it ready made. The best kind is universally acknowledged to be "Robin's Starch".

"Ask your science teacher" - Um - we are not all high-school kids, some of us are actually grown up, and one or two of us may even be science teachers!!

Why is starch important in a diet? The article says where it can be found but gave no indication of its nutritional value.

Article says: "Humans and other animals have amylases, so they can digest starch. Digestion of starches consists of the process of the cleavage of the starch molecules back into their constituent simple sugar units by the action of the amylases. The resulting sugars are then processed by further enzymes (such as maltase) in the body, in the same manner as other sugars in the diet."

See the entry on "glucose."

Basically, starch is an energy store (like glucose,) but can store more energy than glucose. Starch can be broken down into glucose, which in nessecary for respiration and therefore life!

It is broken down into its constituent monosaccharides, not simple sugar units.Stakingsin (talk) 09:13, 11 September 2009 (UTC)

I've just removed peas from the list of stachy foods. Peas are high in cellulose not starch. I suspect their is some confusion here about the difference between cellulose and starch (Both are complex carbohydrates) and this food list may need further cleaning up.

Amylum
Q: Isn't starch named amylum?

A: Amylum is a common synonym for starch. It is also the name of a Belguim-based starch company owned by Tate & Lyle.

Making starch
Q: Why can't you make starch?

A: You can make starch. From glucose, e.g. It is simply not economic since extracting it from plants (as described in the article) is    much cheaper.

Solubility of starch?
The article is inconsistent in how refers to the solubility of starch. The Intro and Biochem section say it is insoluble in water, the Household and Test section mention preparing a starch solution. Perhaps boiling is needed, but why? It would be nice if someone could clarify this matter.--InfoCan 17:00, 11 August 2006 (UTC)

Starch -> alcohol
Sorry I am ignorant on this matter, can someone help? Can starch be converted easily into alcohol, and thence to a biologically-friendly fuel?

crystalline to amorphous transition
This must be why bread loses freshness and elasticity in a refrigerator faster than at room temperature, and recovers it (except for drying) in a toaster or oven? When it first cools, it must be in small crystals or still amorphous, but the crystals must become bigger while it remains cool. If this is true, it seems it should go in the bread article. 69.107.93.104 21:29, 19 September 2006 (UTC)

Help with a chemistry project
I've searched and searched but I just can't seem to find the answers to some questions I have about sweet potatoes, i.e. starch. I know the formula is C6H10O5 but I need to define the chemical compounds. If anyone wants to help, that would be great. Thanks. --KangAK 01:26, 21 November 2006 (UTC)

chemical interaction with iodine
"Starch solution is used to test for elemental iodine. A blue/black color indicates the presence of iodine in starch solution. The details of this reaction are not yet fully known, but it is thought that the iodine (I3− and I5− ions) fits inside the coils of amylose, the charge transfers between the iodine and the starch, and the energy level spacings in the resulting complex correspond to the absorption spectrum in the visible light region" Just lovely, but it has no source so I'm giving it 2 days and then I'm deleting it.--I'll bring the food (Talk - Contribs - My Watchlist) 20:39, 8 March 2007 (UTC)


 * I've added a source but it's not the best, I don't have access to the paper on iodine-starch relationships, and I can't afford to buy it. Sorry.--I'll bring the food (Talk - Contribs - My Watchlist) 20:56, 8 March 2007 (UTC)

starch synthesis
ive been searching the web for how exactly starch is synthsised in plants. i know you've said it is possible to synthsise it but its not economical to do so- however, for educational purposes, would it not be beneficial to include details of starch synthesis in nature, including specifically the enzymes involved and detail to the dehydrogenation reaction of glucose in making amylose and amylopectin?

regards

Ally.


 * A college level textbook on plant physiology will have this information. --Una Smith (talk) 03:02, 14 August 2008 (UTC)

Chemical formula
I'm not a chemist, but shouldn't the formula be (C6H10O5)n? Maybe it should be said that C6H10O5 is the repeating unit and that starch is a polymer. I'm not changing it straight away because the "incorrect" formula is sourced and it might be that I've missed the point! Matt 12:57, 13 August 2007 (UTC)

The purpose of such chemical formulas is only to give elemental ratio. They're often used for solids, in which is it assumed that the unit is repeated, so that the claim that C6H10O5 is the chemical formula of starch is certainly not a mistake.

Having said that, the notation (C6H10O5)n for polymers is also well accepted, and will be better suited for this article - so I changed it. Cederal 14:24, 22 August 2007 (UTC)

Isn't C6H10O5 the EMPIRICAL formula, and (C6H10O5)n the CHEMICAL formula? Tazerdadog (talk) 22:01, 13 October 2011 (UTC)

Article Lacking
There is little or no mention of the huge importance of this molecule biologically. Why is it used a glucose storage molecule? What benefits does it provide which have influenced plants to adopt this storage molecule through evolution?

Basic points that i will get around to added post-exams unless this is done before then.

Jebus989 (talk) 20:19, 12 June 2008 (UTC)

Applying starch to clothing
I would like this article to explain how women applied starch to clothing before spray bottles and aerosol cans. Thank you. Marycronkfarrell (talk) 18:41, 15 January 2009 (UTC)


 * I don't have a source to add the content to the article, but this is how it is done: first, you make a paste by taking the powdered starch and mixing in small amounts of water at a time and stirring after each addition (same way as you do when you add starch to stew to thicken it. then you fill a pot with water, add the starch paste to the water, and bring it to a boil. The liquid turns from thin and white to thick and clear. Then you fill a sink/tub/washbasin with water, add the contents of the pot, and dip the items to be starched in the liquid. Wring them out, let partially dry, and iron while damp WITHOUT STEAM. Also note, only cotton, linen, or hemp will take starch.


 * The article states, incorrectly, that all that need be done is mix starch with liquid, and that boiling was only necessary in times past. That WAS true 100 years ago, when pressed cubes of laundry starch were sold that required no boiling; however, no such thing exists in the present time, so the only way that one can starch fabrics at home properly the natural way is to boil the starch. Firejuggler86 (talk) 20:07, 19 June 2021 (UTC)

Types of starch
The article doesn't make very clear (at least to me) the chemical differences between different types of starch, in particular cooked starch versus raw starch. For example it states both that starch is indigestible and that it's the most important carbohydrate in the human diet, an apparent contradiction which is cleared up when you realize it's talking about cooked versus raw starch. But what precisely happens to starch when it is cooked? —Preceding unsigned comment added by 141.209.169.112 (talk) 21:00, 16 June 2009 (UTC)

Assessment comment
Substituted at 06:55, 30 April 2016 (UTC)

Solubility of starch?
I would agree with the problem with the solubility of starch. I boil spaghetti, it does not dissolve. Some clarification of this issue would be good. In this article for example http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Carbohydrates.html It states "Starches are insoluble in water and thus can serve as storage depots of glucose." but in this article it suggests you just need "hot" water. How hot? Randomplanck (talk) 04:27, 7 June 2011 (UTC)randomplanck