Future foodies may need to thank the papaya for velvety smooth ice cream, a sauerkraut-seeding microbe for hypoallergenic soy sauce, and a type of wild rice for protein-rich pilaf.
Although a wide variety of plants and animals have been the focus of genetic modification, new research is proving that there’s still plenty of room at the table for technologies that enhance what we eat while being more socially palatable to cautious consumers. With a battery of natural additives, simple chemical processes and streamlined hybridization strategies, scientists are coaxing unfamiliar properties out of familiar foods, whether for better nutrition, aesthetics or safety.
Three studies published within the past few months, all within the Journal of Agricultural and Food Chemistry, demonstrate the wide diversity of successful food-refining strategies. All share at least one common trait, however: a sizeable potential market.
For ice cream, the growth of texture-ruining ice crystals has long been the focus of manufacturers keen to smooth over a defect that normally makes its gritty appearance in the back of household freezers. “Most of the time, consumers would throw away the ice cream if they feel this sandy texture,” said Srinivasan Damodaran, chair of the Department of Food Science at the University of Wisconsin-Madison. Likewise, ice crystal growth can ruin other frozen foods. “If you freeze meat, the ice crystals can grow and destroy the fibrous structure of the muscle,” he said. “It won’t be very appealing.”
The result, he said, is millions of dollars' worth of wasted food. Damodaran, however, discovered that adding gelatin protein cut into specific sizes with an enzyme naturally found in papayas can dramatically reduce the formation of ice crystals. The researcher simulated the conditions of a typical household freezer, which completes about seven defrost cycles every two months — normally enough time and temperature fluctuation for some serious ice crystal formation. Using a concentration of 1 percent to 4 percent of the tasteless and non-toxic “antifreeze,” called gelatin hydrolysate, “we have shown that we can go even up to 20 cycles with no ice crystal growth,” Damodaran said. “That may translate to six months.”
Researchers from the international food conglomerate Unilever have added an “ice-structuring” antifreeze found in the blood of an eel-like fish called the ocean pout to some of the company’s ice cream and popsicle brands, to achieve the same effect. But the effort has meant introducing the antifreeze-encoding gene into baker’s yeast to obtain the protein in bulk, a genetic modification process that has faced criticism from other scientists and consumer advocates over safety concerns, particularly in the United Kingdom.
“Would the gelatin hydrolysate be a good substitute for that? The answer is yes,” Damodaran said. His process, he said, relies on the same gelatin protein used for hundreds of food products and on an enzyme called papain ingested by anyone who eats papaya. Both products have long been classified under the Food and Drug Administration’s GRAS category, or “Generally Recognized As Safe.” Unilever’s ice-structuring protein won FDA approval under the same category in 2003 and has since been added to some products sold in the U.S. and other countries. It has yet to be introduced in the United Kingdom, however, where genetically-modified foods have faced a more hostile reception by consumers.
Although Damodaran hasn’t yet applied for a patent or begun test production of gelatin hydrolysate-containing ice cream, he said he’s received plenty of inquiries and the university’s dairy plant could be quickly called into service to make small test batches.
Soy, a fast-growing food additive in the U.S., also ranks among the top eight allergens identified in the nation’s product labeling laws, along with milk, fish, eggs, peanuts, wheat, shellfish and tree nuts such as walnuts. An estimated one in 200 adults is allergic to soy, but the allergy is more common among children. Elvira de Mejia, an associate professor of food science and human nutrition at the University of Illinois at Urbana-Champaign, said fermentation with benign microorganisms may be one way to solve the problem.
Starting with soy flour, de Mejia and her collaborators used both a liquid and solid fermentation process. When the team tested the resulting liquid and paste on blood plasma from volunteers with soy allergies, “we found that the allergenic [protein] production was lowered by 99 percent, depending on the type of microorganism used,” she said. The bacterial species Lactobacillus plantarum, common in both sauerkraut and sourdough, was tops at knocking out the soy allergens. De Mejia’s group has since tested the soy on allergic piglets and found that the fermented forms reduced skin reactions and diarrhea.
The process also increased the concentrations of some essential amino acids, raising the researchers’ hopes that the process might also improve soy’s nutritive value. Fermenting it, of course, changes the flavor, but de Mejia said the growing popularity of miso soup, soy sauce and tempeh cakes suggests that Americans are becoming accustomed to fermented soy products already ubiquitous in Japan. And in Europe and other parts of the world with heightened concerns over genetically modifying crops, a natural method such as hers presents a viable alternative to removing soy allergens through genetic engineering, she said.
Boosting protein in rice
Improving worldwide nutrition has been another central goal of recent research. Hari B. Krishnan, a molecular biologist at the U.S. Department of Agriculture’s Agricultural Research Service in Columbia, Mo., said protein deficiency is a major concern in many developing countries, where people often depend on rice as their main food source. Most commonly grown rice varieties, he said, contain a protein content of between 6 percent and 9 percent. “If we can somehow increase that, even by 1 or 2 percent, that could be very important for the billions of people who consume rice.”
Krishnan and his collaborators at India’s Tamil Nadu Agricultural University may have succeeded by crossing two species for a completely different reason: to incorporate drought-resistance from a wild Indian variety into one commonly grown in Southeast Asia. When tested, the hybrid surprisingly boasted a protein content of 12.4 percent, significantly more than either parent. The hybrid, Krishnan said, could be used as a breeding line and crossed with popular varieties to maximize both cooking quality and nutritional value. The team has observed no downsides to the new hybrid, through tests are still ongoing with regard to yield and whether the high-protein trait can be maintained for several generations.
Krishnan said the most efficient way of adding new traits still often involves genetic engineering. Golden rice, for example, has been modified to contain a higher amount of beta-carotene. Despite the promise, however, “certainly, it’s not compatible with some countries” due to widespread opposition, he said.
Doug Gurian-Sherman, a senior scientist at the Cambridge, Mass.-based environmental organization Union of Concerned Scientists, said other advances in plant breeding have led to faster crosses under the banner of a technique called marker-assisted selection. Thanks in part to more accessible genetic information, the increased ability to tap naturally-occurring diversity in rice, corn and other food crops has yielded plants with higher iron and beta-carotene levels, for example — without the need for genetic modification.
GM WATCH, a United Kingdom-based organization that has aggressively campaigned against genetically modified food for the past decade, released a January report pointing out other fruitful efforts toward producing a salt-resistant wheat hybrid, parasite-resistant black-eyed pea plant and virus-resistant cassava variety, among recent examples, as further evidence that food enhancement need not rely on genetic engineering.
“There’s still a significant amount of resistance to genetically modified foods in Europe and Japan and other parts of the world,” Gurian-Sherman said. “But there’s been no opposition over using conventional breeding to produce the same traits.”
He cautioned that new breeding practices are not a panacea — “like any new technology” — but pointed out that because they’re largely unencumbered by public opposition or the approval process required of genetic modification, such techniques are sometimes yielding faster and more cost-effective end products. “When you use technology that uses products that are already part of the food supply, then the regulatory burden is much lower,” he said.
Indeed, researchers have revisited basic science within the past few months to demonstrate the surprising benefits of foods altered by simply cooking them. Alabama scientists, for example, found that boiling peanuts increases their antioxidant value above either roasted or raw ones, while Italian scientists concluded that steaming broccoli actually boosts its concentration of cancer-fighting compounds known as glucosinolates.
Now if only researchers could discover how to make vegetables as irresistible as ice cream.