| MadSci Network: Biochemistry |
First I went to that font of wisdom, the MadSci Archives. There I found a posting that says “maybe”.
What is modified cornstarch? Click here to get a MadSci answer.
It suggests that some form of modification will allow cookless gelling of modified cornstarch. Why do I say maybe? Because there are many different possible modifications to cornstarch. Let me give you a quick part of the answer. There is a brand of “precooked cornstarch” that allows gelling without further cooking, Instant Clear Jel.
There is also a brand of guar gum that does the same, Quick Thick’ner.
The Food and Drug Administration defines what is considered "generally recognized as safe" (GRAS). It considers a variety of treated forms of starch to be GRAS. Here is the FDA definition of starch, the starting point for modified cornstarch. Basically the FDA says that legally starch is only cornstarch. How the potatoes, and other plants that make starch feel about this is hard to tell. The FDA knows that is not really the case. In other places the FDA admits that starch is the reserve carbohydrate in tubers such as potatoes, in grains such as rice, corn, or barley, in seeds, and in many fruits.
Here is the FDA’s definition of “food starch-modified”. The Code of Federal Regulations, Title 21, Volume 3, revised as of April 1, 2004, Sec. 172.892 says you can call cornstarch “Food starch-modified” after you torture it in any of the following ways, singly or in combination:
| 1) acid-modified by treatment with hydrochloric acid or sulfuric acid or both. |
| 2) Oxidized (often called bleaching) with hydrogen peroxide, potassium permanganate, ammonium persulfate, and sulfur dioxide, or propylene oxide. |
| 3) Sodium hypochlorite. |
| 4) Acetylated with acetic anhydride. |
| 5) Phosphorylated with adipic anhydride. |
| 6) Esterified with acrolein, epichlorohydrin, 1-octenyl succinic anhydride, vinyl acetate, sodium tripolyphosphate and sodium trimetaphosphate, or phosphorus oxychloride with propylene oxide. |
| 7) Hydrolysed with a mylolytic enzymes: alpha-amylase, beta-amylase, glucoamylase, isoamylase, and pullulanase. |
| 8) Hydrolysed with sodium hydroxide. |
So it looks like “food starch-modified” is not just one thing. It can come in a variety of forms, each designed to be different or cheaper or easier to make. I suspect that patents get assigned to each of these new treatments as they get invented. My advice is to do experiments on the modified cornstarch (or cornstarches) of your choice and determine whether they can thicken with water out of the tap. Use cold water and hot water, and try some with and without some vinegar andl also with and without some salt because these may affect how the starch molecules loosen up from the granules.
I found an excellent article on the properties of these various modications.
I happen to think cornstarch is a marvelous ingredient for MadScientist experimentation. Here are some links to other MadSci postings about cornstarchy facts:
How about ... Slime? Slime Instructions!
What makes glues stick? Did you know that library paste was mostly cornstarch and water? (No wonder I liked eating it in second grade!) And did you know that corrugated cardboard was held together with starch glues?
Why does an uncooked cornstarch+water mixture get thicker when stirred? (This property is called dilatentism.)
Here is another item on the same topic.
What is Xanthan gum? Turns out to be a lot like cooked cornstarch.
And finally a large excerpt from A facinating article on making condiments from a magazine called Food Product Design, September 2003 -- “Condiment Cover Up”, by Donna Berry.
| -------from the end of article----- |
| The plot thickens |
| Fruit pastes and powders also provide viscosity to condiments. However, the finished products often require stabilizers for desired viscosities, particularly dipping sauces, where the condiment must adhere to the food being dipped. Because these ingredients can impact flavor and flavor release, selecting the right stabilizing system is not always easy, particularly with some of the more exotic, bolder flavors with which designers are experimenting. |
| “For most condiments, salt-tolerant gums such as xanthan and guar may be used as thickeners or suspending agents,” says Florian Ward, vice president of research and development, TIC Gums, Belcamp, MD. “Usage levels are at around 0.5% to 1.0%, depending on the product. In condiments with high oil levels, an emulsifying gum like propylene glycol alginate may be used in addition to xanthan gum or guar gum.” A shear-thinning hydrocolloid, xanthan gum regains viscosity once shear is removed, which makes it ideal for applications that require pouring or squeezing. |
| Starches can also stabilize condiments, with modified cornstarch typically used because of its flexibility in processing tolerance, particularly with low pH, excessive shear and high temperatures. However, starches can be derived from a variety of sources, with each starch possessing unique characteristics. For instance, tapioca- and potato-based starches, which both have a very bland, clean flavor due to their low lipid and protein content, behave differently in condiments. Tapioca starch gives a smooth, shiny texture, while potato starch provides pulpiness. The latter can cut costs in salsa, as it allows for a reduction in fruit solids. |
| At IFT, AVEBE America Inc., Princeton, NJ, offered samples of a cold-processed, solids-reduced mild salsa made with 3% cold-water-swelling, modified potato starch. The starch provided body and viscosity, gave the salsa a slightly pulpy texture, and reduced solids by 20%. |
| The types and amounts of starch and gum vary depending on the application, and whether the condiment is to be poured, spooned or squeezed. Over-stabilizing condiments can make the product overly thick and unnatural, and can reduce the functionality of the system or mask flavors. |
| -----END OF ARTICLE----- |
Looks to me that you could write a book about "food starch-modified". You could learn a lot of organic chemistry by studying it. And it is great stuff to play with.
Have fun,
David Winsemius, MD
Try the links in the MadSci Library for more information on Biochemistry.