Some innovations are just a little hard to swallow. Consider, for example, U.S. Patent No. 4,948,602.

Two RJR Nabisco Inc. researchers were just awarded this patent for inventing a "volcano" cookie that literally erupts to spew flavored "lava" through the top and down the cookie's sides when it is heated in a microwave oven. The microwave energy triggers a rapid expansion of the cookie's water-based filling and whoosh -- you have a tasty little Vesuvius to pop into your mouth.

Wanting to talk to these aspiring Edisons of edibles, I called up and down Nabisco's organizational chart only to be informed by a high-ranking corporate official that "everything in regard to that cookie is proprietary ... no one is allowed to talk about that cookie." Clearly, RJR Nabisco Chief Executive Louis V. Gerstner has a tougher job than I thought.

Getting food -- whether baked goods or breakfast cereal -- to "perform" turns out to be one of the great ambitions of America's mass-market food giants such as Nabisco, General Foods Corp. and Campbell Soup Co. Instead of bread and circuses to keep the masses happy, why not turn the bread into circuses?

"It's sort of a pot of gold, a Holy Grail," asserts Martin Friedman, who edits Gorman's New Product News, an influential trade journal that tracks culinary innovation. "How do we make something happen?"

Rice Krispies weren't sold on taste; they were sold on snap, crackle and pop. Breakfast cereal marketers have racked their brains and spent millions of dollars studying the chemistry of milk to get their cereals to perform when the milk hits the bowl.

"Anything that has play value in the food confers a competitive advantage," says Friedman, citing an oatmeal on the market that, when "you pour hot water on it, little chewable bears appear."

Obviously, there are thin lines between novelties, gimmicks and genuine entertainment. But as the technology surrounding food changes, so do the metaphors. It used to be that food was something you ate. Listen to the nutritionists and the vegetarians, and all of a sudden food becomes a form of medicine. Watch a McDonald's ad and food is the stuff of family values and social bonding.

So what happens when food is designed to be entertaining? You get chewable bears and Last Days of Pompeii volcano cookies. You get people looking at food technology as a medium. Milk isn't just the liquid that's mixed with the cereal; it can be the fuel that makes cereal speedboats skim around the bowl. Similarly, the microwave oven is no longer just a tool to make cooking quicker and more convenient; it's a medium with unique properties that can get food to perform in unusual ways.

"It's food as a performing art," says Pat Custis, the group marketing research manager at Campbell Soup's Microwave Institute. "Microwave is one area where people expect the cutting edge of innovation. ... There's a certain amount of magic that goes into the microwave; it's the microwave as a black box -- no one really knows how it operates. There's an element of mystery and fun. That's why one of the first foods people buy for it are things like popcorn followed by cakes and snacks."

According to Custis, roughly three-quarters of American households have microwaves. The microwave food market approaches $3 billion in annual sales, and the average family pops something into the oven 2.5 times a day.

Classic marketing theory dictates that you want to sell microwave products that aren't commodities but instead have unique properties that can intrigue the eyes as well as the taste buds.

Tap into the properties of microwave energy and you can design foods that do more than just satisfy a sudden craving for a snack. You can design an entertainment experience that makes you want to hook your VCR up to the oven.

That volcano cookies might be the culinary lava lamps of the 1990s is beside the point. The real point is that people who design microwave food are viewing the device as much as a television set as an oven. The microwave becomes a medium for entertainment as well as food. Indeed, Campbell's Custis predicts that we'll soon see a microwave button on our TV/VCR/CD remote control devices so we can program our snacks along with our channels.

The possibilities for multimedia food become even more interesting when you consider the role biotechnologies may play. Engineer a few proteins here, tinker with a few genes there, and you could get food that curls into Mobius strips or changes colors or glows or expands into interesting shapes.

Food scientists are looking for organic chemicals that can make foods crisp and brown in a microwave oven. Biotechnology and microwave radiation may be the most intriguing set of food technologies since the invention of the spear and fire. The underlying theme remains the same: We're designing food to perform to our expectations -- whatever they may be.

It's certainly not clear that people want to be entertained by their food. A precocious 7-year-old might enjoy a breakfast cereal that turns into surrealistic Cubist art when you add milk; most of my contemporaries would not. I like the idea of watching a cookie erupt in the office microwave; after the 10th time, I'm not so sure.

Then again, I'm perfectly content eating the same kinds of food over and over again. Why wouldn't a provocative visual or tactile twist make the eating experience more memorable or enjoyable for me? Four-star restaurants pride themselves on food presentation; why not prepare food that presents itself?

As New Products's Friedman points out, if the food isn't "organoleptic" (i.e., appealing to all the senses), it's not going to sell; it's doomed to be a gimmick. However, it's clear that technology is moving food away from something that appeals just to our appetite.

It may well be that this could turn out to be the equivalent of chrome grilles and tail fins, but I'm willing to bet that, just as ethnic foods and microwave snacks have won a large share of people's diets, foods that entertain will also capture their following. This is a culture that wants to be entertained. I think it's just as willing to look at the screen of a microwave oven as the screen of a Sony television set. It's simply a matter of taste. Michael Schrage is a columnist for the Los Angeles Times.