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Industrial Thanksgiving: Science Takes Mom’s Recipes to the Assembly-Line

Posted: 25 Nov 2009 12:22 PM PST

Industrial Thanksgiving

Thanksgiving is about eating, and though local, organic food might be what the cool kids are eating, most people are still eating products of the industrial food system.

Whether you're talking turkey, cranberries or potatoes, industrial-scale processes have been developed to drive down food costs, drive up corporate profits and feed America's incredible hunger for novel food items.

But most consumers of these manufactured meals have little or no knowledge of the machines and methods used to freeze turkeys, turn potatoes into fake potatoes, and cranberries into TV-dinner cranberry sauce. It's not always pretty, but food scientists' epic battle to scale up your mom's recipes without making them taste nasty is worth examining, if not giving thanks for.

Turkey is the most iconic component of any Thanksgiving meal. Extensive breeding programs have seriously genetically altered the birds that millions of Americans eat. The birds have more than doubled in size since 1930 to an average of 28 pounds today. Even though we generally eat them whole, and therefore less processed than other meals, food technologists have developed new ways of freezing turkeys to increase their edible life, which according to the USDA is just one or two days for fresh turkeys.

A 1990 patent secured by food processor Swift-Eckrich (now Armour Swift-Eckrich) describes a method for freezing turkeys faster than traditional air-chilling. Salt, water and propolyene glycol — a major and generally nontoxic component of airplane de-icers — are cooled down to less than minus 5 degrees Fahrenheit. Because the propylene glycol and salt lower the freezing point of the water, the liquid remains unfrozen. The turkeys are either sprayed with the solution or immersed in it, in a tank like the one below.

Even the largest bird noted in the patent, a 19-pounder, froze within 7 hours, 10 minutes, as compared with the 24 to 48 hours blast-chilling would need.

A turkey freezer.

According to the patent, the "flavor, texture, and quality of the thawed product is excellent," displaying none of the "objectionable medicinal or other flavors and aftertastes" of previous similar processes.

But processed turkeys are just the beginning of our industrialized holiday feast. Cranberries and potatoes have received even-more-transformative treatments by food scientists.

Traditional mashed potatoes are simple to make. You peel potatoes, cook them until they're soft, and mash them. But potatoes don't last that long, and they're heavy and bulky to transport. Food companies wanted a lighter, longer-lasting product.

Enter the potato flake. Growing out of research on potato granules, the flake was a type of dehydrated, heavily processed potato that could be heated with water and fat to make a product closely resembling the hand-mashed variety.

The potato flake process was established by 1967, with variations coming from several companies. Overton Machine Company patented the process depicted below.

potato-flakes

As shown in the diagram, there are a few more steps to this process than the one your Mom uses. First, the potatoes are heated for a few minutes at about 170 degrees Fahrenheit. Then, they're bathed in a caustic lye solution, which is used in manufacturing aluminum and paper, and as a cleaning agent. As you might expect, that softens them up, which makes the peeling step easier. Removed from their skins, they are bathed in a solution that neutralizes the pH.

Then, they head to a slicer that cuts them into half-inch chunks. Those are precooked in hot water, cooled, and then cooked again at about 200 degrees. The potato pieces are then doused with some preservatives and pushed through a ricer to make them smaller. Finally, the potato particles are placed on a dryer at a thickness of less than 1/100 of an inch. Voila, potato flakes!

"This invention now provides a process and apparatus for the production of uniform, high-quality dehydrated potato flakes which will reconstitute into a most palatable food which cannot be distinguished from the naturally occurring cooked potatoes," the patent contends, "despite variations in growth techniques, geographical areas or potato varieties and with substantial reduction of required processing materials, equipment, time, and cost."

Of course, if you prefer baked potatoes, another inventor has a product just for you. Miles Willard of Idaho Falls was granted a patent in 1979 for the "Preparation of Fabricated Baked Potato Product."

It's like a traditional baked potato, in that its potato interior is enclosed in potato skin, but that's where the similarities end. For example, the potato skin is, "preferably made by baking peeled potato pieces to impart a baked potato flavor, grinding the baked pieces, and mixing the ground baked-potato pieces with water, starch and cooked potato solids to form a pliable, cohesive baked-potato dough."

This dough is then wrapped around a potato mash created basically through the flake process described above minus the dehydration. Then it's fried. It's not just a baked potato that was heated in a dry oven: It's many potatoes baked and mashed and then reassembled into something that kind of looks and tastes like a baked potato. The point? It cooks in just minutes instead of the hour required for regular potatoes.

Potatoes like that would be convenient in a TV dinner. These prepackaged, microwavable meals present a variety of challenges to the food engineer. How, for example, can cranberry sauce be included with turkey dinners that will be packaged, frozen and heated all together?

"Cranberry sauce is now so widely recognized as an almost indispensable accompaniment of any turkey dinner, that it is sorely missed when omitted from turkey TV dinners," a 1967 Ocean Spray patent noted. "Yet, such cranberry sauces are not often, if ever, included in frozen dinners, primarily because of difficulties encountered by reason of their peculiar processing characteristics."

Cranberry sauce is held together by pectin found in the cranberries themselves, and it must be allowed to set. or it loses its texture on freezing and reheating. But when it's set, the mechanical methods necessary to actually place it next to the turkey in the dish bust up its structural integrity. That leads to the same problem that TV dinner makers encountered when they stuck ungelled cranberry sauce to the meals. The flowing liquid "flows into and colors the other components of the dinner."

This terrible dilemma was temporarily solved by hand-plating (!) jellied cranberry just before the TV dinners were frozen, but that was "too slow to be compatible with the automated high speed of the rest of the production line."

So Ocean Spray developed a solution with just the right mix of ingredients. All it took was mixing and heating 500 pounds of cranberries, 30 pounds of waxy maize starch, 60 gallons of Briz sugar syrup and 30 gallons of water. The corn starch is heated up and added to the cranberries This causes the mixture to gel almost instantly into a solution that won't break down upon freezing and reheating, transforming the relationship between TV dinners and cranberry sauce forever.

"Such cooked cranberry-sauce mix thus need not be held for any gelling period after cooking, but may be rapidly metered hot directly from the cooking kettles onto individual TV dinner plates in the freeze-line of production without danger of losing gelation," the patent triumphantly concludes.

Image: Jon Snyder/Wired.com

See Also:

WiSci 2.0: Alexis Madrigal's Twitter, Google Reader feed, and green tech history research site; Wired Science on Twitter and Facebook.