Gluten in Food

Where is gluten from wheat, barley, rye and oats used? A surprising number of processed or manufactured foods contain gluten. The nature of the gluten protein is such that it is not necessary to have a whole protein complex, just short peptide chain fragments (7 - 20 amino acids) from the original protein. The fragments are characterized by the presence of more than one “proline” (one of the twenty amino acids) near another one in the chain. Proline causes there to be a kink in the peptide chain, and foils all human digestive enzymes – they can’t grip it properly to take the chain apart – so intact peptide chain fragments remain. Cooking may break the large protein apart, creating numerous offensive fragments, leaving them invisible, even in a clear liquid.

The most obvious basic uses include bread, pasta, cereals, rolls, cakes, cookies, pastries, pizza, pie crusts, croutons for salad, and as a thickener in fruit sauces, gravies and soups.

It is the main ingredient in some types of “natural flavor” which is made by extracting gluten from wheat, and cooking it to achieve browning of the protein, and just as in browned meats, a lot of good flavor is developed. Not enough cooking takes place to destroy the proteins, so when it is added to pre-cooked frozen meats to enhance their flavor, the stuff tastes pretty good. This ingredient can be found in many types of packaged meats such as hot-dogs, sandwich meats and uncooked preformed frozen meats. It is used in many places that seem, at first glance, unlikely.

Hydrolyzed vegetable protein (HVP), and hydrolyzed plant protein (HPP) may be made from the gluten in wheat.

It has found application in restaurant supply pre-cut steaks and burgers that have been printed with a pattern that makes it look like they were cooked on a charcoal barbecue, complete with crossed brown stripes – even though it is cooked on a flat metal surface restaurant cook top. There are now even direct consumer items being treated this way.

Gluten has turned up, surprisingly, in distilled vinegar. Most of this material is made from wheat, crushed and treated with enzymes to turn the starch into sugars, then fermented with yeast to produce alcohol. This fermented mash is distilled to concentrate the alcohol, and then treated with one more bacterial process to oxidize the alcohol into vinegar.

     H   H                   H    O
     |   |                   |   //
 H - C - C – H    ->     H - C - C 
     |    \                  |    \
     H     O – H             H     O – H

 Ethyl Alcohol         Vinegar     
After filtering, the acid is diluted with water to 5% and bottled as White Vinegar or Distilled Vinegar.

The gluten problem stems from the distillation process: boiling a mixture of alcohol and partially cooked and digested wheat gluten protein results in atomizing small droplets of the slurry. Every time a bubble rises to the surface and bursts, small droplets are left hanging in the air. As the lower part of the bursting bubble collapses into the middle, a jet of droplets is ejected into the air. The smallest remain floating, while the largest few fall back to the surface where they splash and break, dispersing even more mist of the original liquid. The droplets form a mist that is carried along with the alcohol vapor into the condensing unit where it joins the alcohol liquid in running down into the distillate collection container.

The resulting product is somewhat concentrated alcohol with a small amount of gluten-derived protein/peptide “solids” that are too small to be removed by filtering. (If you just allowed the liquid to evaporate, a sticky residue would remain.) Once the alcohol is converted to vinegar, the acid prevents clouding from the protein, and simple filtration to clarify the liquid suffices to make it into a usable long shelf life product.

Distilled vinegar is used in many food products, from salad dressings, to condiments, relishes, and sauces. Some food products manufacturers are not careful about correctly labeling the vinegar source, substituting distilled vinegar as ingredient costs change. So products that just label an ingredient as ‘vinegar’ may sometimes be okay, and other times be a source of gluten protein.

Gluten has found its way into soft drinks as a texturizer/smoothness promoter. Of course beer is made from barley, and many distilled alcoholic beverages are made from “Grain Neutral Spirits” which are distilled from fermented wheat mash, and have plenty of protein carried over during the distillation processing. Even extra distillation and multiple stages of filtering is not enough to make the alcohol gluten free.

Of course the US standards for alcoholic beverages allow any of them to be made using “grain neutral spirits”, so watch out for rum, which should be made from fermented molasses, but may be legally extended with grain neutral spirits. Even a potato vodka can have it added, so check with your favorite distiller.

Fried foods are often a source of cross-contamination. Fritos or any other brand of corn chips may have been fried in oil that was used to fry other foods that employ flour-based coatings. Once the oil has been used for anything containing gluten protein, it will impart enough gluten content to subsequent production to cause problems. Sometimes potato or corn products might be the first items processed in a new batch of cooking oil, and they will be okay, but there is no easy way to tell. So all bagged chip products, unless you know they are okay must be suspect.

Restaurant deep fried foods are also a source of strong carryover from breading on some products. But restaurants have other routes for cross contamination, from airborne dusts to spreading crumbs on clothing, utensils, cutting surfaces, and multi-use cooking surfaces. It takes special training and separate preparation areas to know how to serve gluten free foods in an ordinary restaurant.

Surimi – that attractive looking manufactured faux crab meat has a good dose of wheat gluten serving as a texture-building ingredient.

Chinese food – especially when prepared in a restaurant - may be “velveted”. This is a simple treatment given to items to be steamed, in order to impart a smooth mouthfeel surface texture. This is accomplished by wetting the food item, such as shrimp, then dipping it is a thin slurry of starch, which might just be wheat flour instead of corn starch. Enough material is retained to develop a very smooth texture without any visible change in the appearance after the material is steamed.

Soy Sauce used to be made by fermenting soy beans, but after enough years of adaptation, the most flavorful soy sauce now has wheat as its main ingredient. And soy sauce is used as an ingredient in many prepared/manufactured foods. Several other sauces contain soy sauce, as well as distilled vinegar.

Corn Tortillas are made on production lines in factories, usually along side production lines making wheat flour tortillas. Although they may be run on separate production equipment, these factories typically have a lot of flour dust floating about, and cross contamination can be severe. One company’s product caused a reaction after three days of consuming one serving a day. The company tested their product using a lab procedure known as ELISA, (which has a lower detection limit of ten parts per million,) with a negative detection result. (So 10 ppm is still too much gluten if you eat enough of the product.)

Other surprises include the places where wheat flour and wheat derived ingredients and materials are used. It is what holds “corn bread” together, although it may not be the main ingredient. It has also found its way into many places such as candy production, where it has been sprinkled onto conveyor belts to prevent chocolate from sticking. Envelope and postage stamp adhesives are another hidden source, and it has also been used as an ingredient in the manufacture of charcoal briquettes and in foamed plastic food trays to make them more biodegradable. Cosmetics, pills (even some prescription medicines), toothpastes and hair-care products have sometimes used gluten-containing materials as ingredients. It has been used as a carrier for some spice mixtures, and may sometimes be found in curry.

Some food production companies seem to have a sensitivity to the Celiac Disease persons concerns – and are extremely careful in food manufacturing. These companies maintain absolutely gluten-free manufacturing facilities and never allow the wrong ingredients in the door. A few of these even label their products as “Gluten Free” and can be trusted.

Some other food manufacturers apparently do not realize that there is only one way for a sensitive individual to be safe, and fail to inform customers that products they label as Gluten Free were really made on the same production line as gluten-laden products, and that there can be significant cross contamination. (Salad dressings come to mind.) Other companies claim separate processing equipment, but ignore cross contamination from airborne dusts. A supplier of milled grains claims that their methods are “good enough” to allow them to claim some of their products to be gluten-free, even though more sensitive Celiacs experience a reaction after consuming them.

The lessons become so complex that in the long run it is actually simpler to start with “known safe” food products and ingredients and create everything from scratch. There are now numerous cookbooks meant to help the Celiac Diseased survive, although many of them seem aimed at replacing pastries and breads – high carb comfort foods – while some do cover the basics. There are many creative methods of achieving delightful variety and incredible flavors without the use of wheat, barley, rye, or oats. There are even some really good ways of rebuilding items such as salad dressings and main-dish sauces that seem almost magic in their simplicity, while being truly amazing in their excellent character.