Dreaming of the
March 1998 -- Perspectives
By Suanne J. Klahorst
What do food product developers dream about at night? Judging from product introductions, it must be the perfect fat substitute.
Idealized fat ingredients usually start out as part of a group loosely referred to as the "specialty" fats and oils. The term specialty fats is open to interpretation. One definition pertains to cost, since they command higher prices than commodities. Today's specialty oil has the potential to become tomorrow's commodity oil with competitive pricing and adequate supplies.
Fat wasn't always the dietary bad guy. Remember when sugar was the villain? Like sugar, fat suffered a bad reputation because of a natural tendency to eat too much of something that tastes so good. Thanks to today's low-fat and nonfat options, we can pick and choose fats to gain the recommended 30% of our daily caloric intake.
If the perfect fat could be dreamed up, what would it be like? It would offer the correct ratio of unsaturated to saturated fatty acids to meet nutritional recommendations. It would crystallize at the ideal temperatures for optimal flavor, texture and appearance. It would afford long-term stability during processing and shelf life, without adding antioxidants.
It would be abundantly available, cost-effective, and provide less calories. It would offer such flexibility that it would reduce the number of fat ingredients needed. We can almost see the fat in our dream now, but just as we open the box, the alarm goes off. We have to wake up at the critical moment, because there is no such thing as a perfect fat, except maybe in our dreams. Or is there?
What is a specialty fat?
Canola is a classic example. Before selective breeding to remove erucic acid, it was known as rapeseed. After it was modified and renamed canola (derived from "Canadian oil, low acid"), it became popular. The growth of the canola market took place as a result of marketing, agriculture and timing. Ten years ago, the food industry made a push to eliminate saturated fats. Canola helped meet the need for alternatives, producing a "halo image" among the unsaturated oils, says Willie Loh, market development, Cargill Foods, Minneapolis.
Beyond commodity oils, a new class of products has sprung up. These identity-preserved oils are those that are grown, harvested and processed separately from regular oilseed crops, says Ken Player, national sales manager, AC HUMKO, Memphis, TN. "For the most part these are the hybridized varieties such as high-oleic varieties of sunflower and canola oil. The hybridization process has enhanced selected fatty acid profiles and properties. They are contract crops, and consequently they must be isolated so they don't cross-pollinate; they are crushed separately."
The term "specialty" denotes added value. For oil-seeds, one way to add value is to minimally process in order to preserve the attributes of the native oil. Niche oils, such as olive, walnut, rice bran, sesame and fish, are characterized by images of purity and healthfulness, as well as unique flavor attributes.
The extraction processes are often listed on the label: virgin, first press, cold-pressed or expeller-pressed. Only niche markets can absorb the processing costs, and production is limited compared to commodity oils such as canola, soybean or palm oils, which are consumed in millions of metric tons annually.
The next two oils expected to move out of the specialty segment are sunflower and safflower oils. Sunflower oil, favored for high levels of polyunsaturates, now has improved oxidative stability through the development of high-oleic varieties. Oxidative stability of polyunsaturates increases when linoleic and linolenic fatty acids are replaced by the monounsaturate oleic acid. These new varieties of sunflower and safflower oils are showing up in fried snacks designed to attract the health-aware market segment. Research is under way to improve sunflower for increased yields, making these oils even more available for adding health appeal.
Fish (menhaden) oil is sought after as a nutraceutical food ingredient. It adds little functional value in terms of flavor or stability. However, medical and nutritional literature links its long-chain omega-3 polyunsaturated fatty acids (PUFAs) to the prevention of a long list of diseases. As a result, it has been incorporated into numerous foods in Japan and Europe.
Because the world's fish supply is rapidly diminishing, transgenic biotechnology may be required to significantly increase the supply of omega-3 PUFAs.
PUFAs have potential to balance the saturated to unsaturated ratios of fats. One current example is EggsPlus, from Pilgrim's Pride, Pittsburg, Texas. The eggs are laid by chickens fed a diet rich in flaxseed and fish oil -- the PUFAs carry through to the eggs, and redeem the nutritional reputation of the cholesterol-rich egg yolk.
This oil is attracting so much attention, we can expect to see R&D investments for identifying similar, alternative fats with similar health benefits. The quest for nutraceutical fats that lower cholesterol are pulling such companies as DuPont, Dow Chemical and Monsanto into food ingredient research.
If "specialty" fats or oils meet a particular customer need, then almost every fat offers a solution to a problem, or it couldn't compete in the value-added ingredients market. Processes, such as hydrogenation, interesterification, fractionation or custom blending to meet functional specifications, enhance value. Hydrogenated soybean oil is commonly used for frying, because of its oxidative stability. A hydrogenated soybean oil that is low in trans fatty acids is an example of a specialty oil that offers a solution to a new problem.
Health experts and the oils industry are evaluating the controversial issue of dietary effects of trans fatty acids. If trans fatty acids labeling is required, specialty oils designed to replace them are expected to take off.
Interesterification could replace hydrogenation and solve the trans dilemma. It uses a catalyzed process to redistribute the fatty acids on the glycerol backbone. Generally the redistribution is random, but manufacturers have developed specialized processes that give directed interesterification.
"Interesterification is most widely practiced in the process of lauric fats and oils to make cocoa butter substitutes to improve the melting profile and reduce the melting point," explains Player. "It doesn't change the fatty acid content, it changes the triglyceride profile." Interesterification is widely used in Europe to increase the beta prime crystal formation in vegetable-oil-based margarines. This increases the stability and creaminess. "You still maintain a relatively flat SFI profile in these oils, so, unlike laurics, the primary reason to use this is to produce reduced trans fatty acid products," he continues. "The primary difference with this technology is that hydrogenation gives better control of the melt point and the steepness of the curve by the method -- selective vs. non-selective -- and the temperatures and pressures used in process."
Direct esterification is the type of process used to form structured lipids. One method implemented in Europe utilizes lipase enzymes to substitute polyunsaturated fatty acids with oxidatively stable fatty acids without forming trans isomers. Typically, the more specific the process, the more costly this becomes.
"If you were to employ direct esterification you could take glycerin and a selected composition of fatty acids -- low melting/high melting -- and make a variety of lipid products to suit the needs of food formulations," says Player. "However, these products tend to be costly."
Another trans-free product is an oxidative-stable blend of cholesterol-free, saturated animal fats. Introduced in 1995 by Bunge Foods, Rolling Meadows, IL, Appetizeô was invented by K.C. Hayes, Ph.D., Brandeis University, Waltham, MA. This product is based on research indicating that not all saturated fats promote elevated cholesterol levels. Some, such as stearic, are considered neutral because they fail to effect a plasma cholesterol increase.
To bring this product to the market, Bunge Foods, Bradley, IL, has partnered with Source Food Technology, Inc., Burnsville, MN. One barrier this product must overcome is that consumers might not recognize its nutritional advantages over trans fatty acids in hydrogenated vegetable oil.
Howard Shuman, team director of Bunge's foodservice division, says that consumer pressure will influence the foodservice industry in moving away from the hydrogenated oils used extensively by fast-food chains.
"My observations from consumer focus groups are that consumers are most clear about the fact that animal fats contain cholesterol and that vegetable fats do not," Shuman says. "However, they still lack a complete understanding of the overall impact that fats and oils have on nutrition, and they are certainly unclear about how trans fatty acids relate to health."
One simple strategy to minimize trans fatty acids is "lightly hydrogenated" oil products. This provides less stability than fully hydrogenating as well as less trans fat. But some frying applications -- with a favorable temperature, size and operation -- can successfully use them. Moderate temperatures and careful handling can accommodate less hydrogenated oils, especially if the oil is continually being replaced with fresh oil that contains antioxidants.
Genetically modified oils, combined with light hydrogenation, offer solutions to the problem of finding unsaturated fat that offers frying stability with minimal trans fat. One lightly hydrogenated canola product currently marketed by Cargill "has a high oleic content that has excellent stability for frying, shelf stability for 18 to 24 months, and a low trans fat content" says Loh.
At the source
Cross-breeding and plant biotechnology have resulted in genetically modified oil-seed crops with fatty acid compositions that function like saturated fats. LauricalÆ, commercialized by Calgene, Inc., Davis, CA, is a canola oil that behaves more like cocoa butter. Another goal for oil-crop modification is replacement of polyunsaturated fatty acids with monounsaturates. This increases oxidative stability, particularly in cooking oils or for spray-coatings that are exposed to oxygen during storage.
Several large oil processors have purchased expertise for developing new oil crops in the form of plant biotechnology companies. If R&D investment is any indication, food processors can expect oils from genetically modified canola, soybean, corn, sunflower and palm oils. In addition to modifying fatty acid profiles, there will be yield improvements through pest resistance. The improved crops are expected to become the new commodities, since growers will need to adopt them to remain competitive. The challenge for the oil seeds industry is reaching consensus on what benefits hold the greatest value, since the R&D cycle is too long to focus on anything except the most promising new varieties.
"Customers (food companies) are risking brand equity when they evaluate a new genetically modified product, so they are looking at not only the ingredient, but the reliability of the company as an ingredient supplier," observes Loh.
A dream of making fat less caloric has resulted in the invention of salatrim, marketed by Cultor Food Science, Ardsley, NY, as BenefatÆ. It still technically qualifies as a triglyceride, but cuts the calories to 4 per gram. Unfortunately the fat calories it supplies are considered saturated on the nutritional label. FDA is considering new labeling guidelines for expressing salatrim's limited absorption. As salatrim is incorporated into the new family of specialty fats, additional structured fat technologies are emerging.
What do these technologies bode for the future? "Commodity oils certainly won't fall by the wayside. What we provide is a variety of solutions, not only identity-preserved oils, interesterified products and the existing products, but utilizing them in component technology," says Player.
Those in the fat and oils industry who perceive problems as opportunities -- whether related to nutrition, function or stability -- have dreamed of some interesting solutions to supplying the "perfect" fat. But one thing is certain, specialty fats will be required to make all product development dreams come true.
Suanne Klahorst is a free-lance food-science writer and food scientist with eight years of experience in the industrial enzyme industry. She is currently with the California Institute of Food and Agricultural Research at the University of California, Davis.