What is "modified food starch"?

People come to this blog for lots of different reasons, but two searches that really seem to pull people in are pumpkin muffins and modified food starch.  This next post has generated a lot of comments over the months.  Hope it helps to demystify this ingredient that is so prevalent in processed foods!

A reader asked me a little while back about the ingredient "modified food starch" - what is it and should it be avoided. Great question! Modified food starch is a very common ingredient, so let's find out a little about it!

Modified food starch can be made from many different grains - corn, wheat, tapioca, etc. - but for the purposes of this discussion, I'm going to focus on modified cornstarch. The principles are the same for all of the modified starches.


Why not just use regular starch?
Let's start by talking about unmodified starch. Starch, a long-chain carbohydrate, is the food reserves of many plants - including corn. In making cornstarch, the corn kernels are soaked and the outer covering removed. The embryo - or the center of the kernel that would form a new corn plant - is also removed. The remaining part of the kernel is mostly starch, which is dried and ground into a fine powder. (For a more detailed description of cornstarch processing, check out this article from the International Starch Institute.) Dent corn, a "field" corn, seems to be the corn most often used to make cornstarch.

Unmodified cornstarch breaks down when heated too much, which is why gravy made with cornstarch is often watery and thin when reheated the next day. Cornstarch also does not hold up well in acidic environments. To minimize the limitations of cornstarch, processed foods often use "modified cornstarch." Cornstarch is modified by applying different reaction conditions to produce the desired end product. The starch can be physically modified, chemically modified, or enzymatically modified. The starch retains its granular form and often resembles the original starch, but the modification results in improved properties.

How is modified food starch used?
Modified food starches are used in a mind-boggling variety of products - luncheon meats, orange juice, baked goods, biofuels, bioplastics, and the list goes on - for a variety of reasons. Modified food starches are used as gelling agents, insuring that foods maintain the correct texture in both frozen and microwaved foods. They're used as thickeners in fat-free dairy products. They're used as bulking agents to increase the bulk of a food without affecting its nutritional value. Modified food starches might be used as an anti-caking agent to keep foods free-flowing, or as an inexpensive way to control moisure in a food product. In low-fat meat products, modified food starch is used as a binder.

Is modified food starch dangerous?
The accepted answer to this question is that modified food starch is harmless. Modified food starch doesn't really have any nutritional value, but it does serve a useful purpose in processed foods. The one concern noted is that manufacturing of modified food starch is not tranparent. There is virtually no way to find out how the modified food starch used in a product was produced - what chemicals or enzymes were used, if used at all, for example - and the possibility of trace chemical contamination bothers some.

I'll note that people sensitive to wheat or gluten should avoid products with modified food starch as an ingredient unless it specifically states that the product is gluten free or states the specific type of starch used. Many manufacturers will use whatever food starch is cheapest or readily available for their product - corn, wheat, or otherwise.

Should you avoid foods with modified food starch?
That's a personal decision. If you don't like the idea of a heavily processed ingredient, then you would probably be happier without modified food starch in your life. Having done a little research, I'm not bothered by this ingredient, so personally, I'm not avoiding foods made with modified food starch.