POLYDEXTROSE is the Pac-Man of food additives. Just as video games have revolutionized the entertainment world, polydextrose and other members of the large-molecule family have the potential of changing the meaning of food.
Polydextrose is one of a growing family of very large molecules called polymers, which are so large they can't pass through the intestinal wall. Thus, like cellulose (better known as fiber), these monster molecules are so large that they can't be absorbed by the body. If they can't be absorbed, they can't be transformed into excess body fat. And, by extension, if these polymers can be chemically bonded to undesirable additives, they, too, will not be absorbed by the body. Therein lies a story.
Researchers at Pfizer, Inc. -- a drug company located in Groton, Conn. -- created polydextrose to replace the bulk of sugar. While artificial sweeteners can (more or less) replace the taste of sugar, there has been a dearth of products to duplicate the texture . Polydextrose appears to be the first product to do so--to replace not the sweetness, but the bulk of sugar, on a cup-to-cup ratio in recipes.
Although it isn't sweet, polydextrose can be used in combination with an artificial sweetener in baked goods, puddings, frozen desserts and hard and soft candies. In fact, said Pfizer's project leader Dr. John Beereboom, expert and consumer taste panels were quite satisfied with the sweetness of baked products where polydextrose replaced half of the sugar (giving the proper bulk but reducing total sweetness).
This textural resemblance, said one Pfizer spokesman, is one of the product's advantages: It allows a manufacturer to tailor-make a sweetener to fit a specific food. Some foods require the bulk of sugar but not the sweetness -- heavy syrup for canned peaches, for instance. Polydextrose could add proper body to the syrup without adding calories or sweetness.
According to Beereboom, polydextrose "holds" tenaciously to water, giving a better "mouth-feel" to foods such as chocolate chip cookies. In addition, it seems to improve the shelf life of baked goods -- they don't turn stale as quickly.
Instead of sugar's 20 calories per teaspoon, polydextrose has only five. When polydextrose is added to ice cream products, it not only reduces the need for much of the sugar, it cuts down the amount of fat required, said Beereboom. Thus calories are reduced in two ways.
Scientists have known about polymers for a long time. Indeed, rubber tires are nothing but one big rubber polymer -- essentially one molecule. Naturally-occurring food polymers, many of them derived from seaweed, are already used in foods as thickeners or stabilizers.
But the science of creating polymers specifically to use in food is relatively new. "We started at ground zero," said Dr. Ned Weinshenker, formerly vice president of the now-liquidated Dynapol research company. "We designed the size, figured out the polymers that would be undigested."
Ten years ago Dynapol was established to use the relatively new polymer technology to create safer food additives. Weinshenker said the organization wanted to create completely new molecules to attach to food colors and additives of dubious reputation so that they would not be absorbed by the body.
Pfizer, too, recently entered the polymer business. It was only five or six years ago, said Beereboom, that "we decided we had something serious" in polydextrose. In December 1978, Pfizer petitioned the Food and Drug Administration for approval. Last June, the FDA cleared the product for various uses, some of which are being market-tested in undisclosed cities.
Implications of the current technology hit many phases of the food industry. Dynapol concentrated specifically on making food additives safer by attaching inert polymers to keep them from being absorbed by the body. The food industry can use polydextrose in many foods, including chewing gum (so that it would not cause cavities), said Beereboom. Polydextrose causes no rise in blood glucose and doesn't increase the need for insulin. Therefore, diabetics might find it useful.
Polydextrose, however, would probably not be suitable for home use, cautioned Beereboom, who said that some expertise is needed to manipulate sweetening formulas and to control texture. "I don't believe that polydextrose will ever be put into the hands of the housewife," he predicted.
Not so with a polymer recently discovered at the University of Dayton Research Center in Ohio. Unlike polydextrose, this sugar substitute -- called polyvinyl -- replaces not only the bulk of sugar, but the sweetness, too.
The trouble with forming a polymer that's sweet, said Beereboom, is that tastebuds react to the specific taste of sugar. Change the molecule, and you change the properties. But Dayton researcher Ival Salyer expects polyvinyl to be an effective sugar substitute. And although experiments are preliminary, Salyer said, the applications of polyvinyl would be similar to those for polydextrose.
Right now, Salyer said, he believes that polyvinyl does not cause cavities, could be used in weight-control and weight-loss diets, and "a diabetic could enjoy a candy bar without worrying about his blood sugar."
Salyer predicted that one could cook with it: that it would cause browning the way sugar does and would react as sugar does during cooking. The product, he claims, has the flavor of sugar and the texture of powdered sugar. "You would cook with it and handle it like normal sugar," said Salyer, "and for sure it would be more expensive."
Sugar and additives represent only the tip of the polymer iceberg, however. Procter & Gamble -- the Cincinnati-based company that makes Crisco -- has published data on a polymer it could use to replace much of the fat in salad dressings, mayonnaise, margarine, cakes -- nearly everywhere fat is used.
While this breakthrough has obvious implications in terms of calorie-reduction (fat packs a walloping 50 calories per teaspoon), research also hints that the product might reduce cholesterol in the blood of those consuming it.
Further, a pharmacologist working at the University of Chicago Medical School said he has developed several large molecules that actually coat the intestinal wall, preventing the body from absorbing anything -- fat, carbohydrates, protein -- the sum total of all nutrients and, thus, calories.
All of these polymers from food-research laboratories are in various stages of development. Yet all eventually have to bear the scrutiny of FDA approval (a vitally necessary scrutiny, agreed most of the scientists). Companies must not only prove effectiveness of the product -- that it does what the manufacturers claim it does -- but they have to prove safety as well.
This means a battery of tests run on many different types of animals whose diets are supplemented with various amounts of the polymer. Polydextrose was fed to rats, dogs and monkeys, and "all the usual tests," said Beereboom, were performed to determine that the products caused no cancer or cell mutations, and that they didn't affect any stages of the reproductive cycle (fertility, fetus formation).
Then Pfizer had to prove that the human body could accept polydextrose. Studies showed that an adult could eat about three ounces a day without adverse effects. The person who consumes too much polydextrose, said Beereboom, would be affected much like the person who ate too many beans--or a bit worse. Still, he said, the FDA requires on any product that contains more than 15 grams per serving of polydextrose a label stating that "sensitive individuals may experience a laxative effect from excess consumption of this product."
Extensive testing has been at least partly responsible for the demise of Dynapol, said president John Cotton. When the company was formed 10 years ago, there was "great potential for these developments," because the safety of food additives was challenged (the FDA banned a red dye, for instance).
Ironically, this climate made it difficult for Dynapol polymers to get approved. While they were awaiting approval, regulations were changed, requiring more and longer studies. Still, polymer research was potentially profitable because food producers were feeling the pressure of food safety concerns. But the picture for polymers has changed recently. "The concern about the safety of food additives has dampened in the last couple of years," said former Dynapol president John Cotton, so the cost of polymers--which are expensive--is less likely to be considered acceptable for this particular use.
Still, all these researchers agreed that there is great potential for the relatively new science.
Perhaps, one researcher speculated, polymers could be added to nitrites to prevent them from being absorbed. Pfizer's Beereboom said the company would like to develop "companion products" for polydextrose -- maybe a polymeric flour.
From the University of Dayton Research Laboratories, Salyer described a technology that would use polymers to develop special properties (such as slow release of certain material when the bondings holding one molecule to another begin to break). "This is a new technology," he said, "and a rapidly developing technology."