Natural Products Insider is part of the Informa Markets Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

New Age Fats & Oils

 
New Age Fats & Oils

November 1996 -- Cover Story

By: Ronald C. Deis, Ph.D.
Contributing Editor

  So much attention has focused on fat-free and reduced-fat issues in recent years that many product developers have overlooked the changes that are occurring in the development of new fats and oils to meet future needs.

  Prior to the 1980s, product developers traditionally used various fat sources for their characteristic flavors and functional properties. Certain fat sources were more suited to certain food products, and higher levels of saturated fats meant more stability so, for example, lard was used for baking and frying (for stability and flavor). It was well known that fats with the highest level of saturated fatty acids were solid at room temperature, and those with more unsaturated fatty acids were liquid at room temperature -- this being the dividing line between fats and oils. If additional functionalities were required, the processor would go beyond the standard refining, bleaching and deodorizing to modify the oil chemically or to blend it with a more saturated fat to give it more plasticity.

  Through a wealth of nutritional and medical studies, we now know that there is a strong relationship between high levels of saturated fats and cholesterol and the incidence of coronary heart disease. This led the Surgeon General of the United States to conclude that "high intake of total dietary fat is associated with increased risk for obesity, some types of cancer, and possibly gall bladder disease. Epidemiologic, clinical and animal studies provide strong and consistent evidence for the relationship between saturated fat intake, high blood cholesterol, and increased risk of coronary heart disease. Excessive saturated fat consumption is the major dietary contributor to total blood cholesterol levels."

  The Surgeon General and a number of other groups have recommended that total fat intake should be reduced to no more than 30% of total calories. Saturated fat should make up less than 10% of calories, polyunsaturated fat less than 10% of calories, and monounsaturates 10% to 15% of calories.

A Shift to Healthy

  The food industry responded to increased public concern regarding saturated fats and cholesterol by sharply reducing the more saturated fat sources from the food supply -- lard, beef tallow, butterfat, coconut oil, palm oil, cottonseed oil, and peanut oil. This posed a problem, since "saturated" translates to "solid" and "stable."

  The food industry and its suppliers worked together to find solutions to some complex problems -- for example, how to provide the same texture, flavor and stability the consumer expected for the same relative price using oil sources previously unused in certain applications. In order to use these oils, the processing industry typically partially hydrogenated them. This slightly increased the level of saturation of the oil, which increased plasticity and stability. This seemed like a good solution, until we found that it created a new issue: trans fatty acids.

  Studies seemed to indicate that the body may respond to trans isomers -- as opposed to the cis conformation -- in the same manner it responds to saturated fatty acids. LDL levels were reported to increase in diets with elevated levels of trans fatty acids, and this increased the risk of atherosclerosis and coronary heart disease. Yet, a 1995 International Life Sciences Institute (ILSI) expert panel concluded that there was little evidence linking trans fatty acids to coronary heart disease risk. The panel recommended additional research to determine whether trans fatty acids had a direct effect on plasma lipoprotein cholesterol concentrations.

  This issue is still hotly debated, but the FDA is considering a regulation to require labeling of trans fatty acids on the nutritional panel. Some have favored grouping trans with saturated fatty acid content on the nutritional panel, so that trans would not merely be replaced with saturated fatty acids to make a "no trans fatty acids" claim.

  The Institute of Shortenings and Edible Oils (ISEO) points out that there has been a general shift away from animal fats over an extended period of time. The Institute notes that "butterfat consumed as butter declined from a per capita availability of 5.2 pounds in 1965 to 3.4 pounds in 1992. Similarly, lard availability (direct use) declined during this period from 6.3 to 1.7 pounds per year." ISEO also points out that we have moved from two-thirds of the visible fat as animal fat in 1940 to one-third in 1966 to 95% of the visible fat as vegetable origin in 1992.

The Shifting Paradigm

  What does all of this mean? The fats and oils industry has reacted to a rapidly changing nutritional awareness of the effects of fat in the diet. Don Banks, an independent consultant (EO Technology) who represents the American Soybean Board, likens the change to buying suits: "We have moved from buying oils 'off the rack' to an industry which now offers 'tailored oils.' Ingredient suppliers, instead of offering a stable of products, must now provide performance based on market need." Some have coined the term "designer fats and oils," which traditionally encompasses fat substitutes such as olestra, as well.

  These rapid changes have often required fast decision-making and the ability to make long-term commitments in research, technology, and grower relationships. All one needs to do to grasp the weight of these changes is to compare a list of suppliers from 10 years ago to a list from today.

  Fortunately for the food industry, we have a tremendous pool of natural sources of "healthy" base oils. The vegetable oils most commonly used in the trend toward "healthy" are soybean, canola, sunflower, cottonseed, safflower, olive, peanut and olive. To give some perspective of the relative amounts produced, about 54% of the world oilseed production is soybean, 12% cottonseed, 11% rapeseed, 10% peanut, 9% sunflower, and 4% other. In the United States, 79% of all edible oil consumed is soybean.

  "Bailey's Industrial Oil and Fat Products" (edited by Y. H. Hui, 1996, John Wiley & Sons) divides fats and oils into 10 categories, including six vegetable oil categories: lauric, vegetable butters, oleic-linoleic, erucic, linolenic, and conjugated acid. Soybean is part of the linolenic group, which is characterized by a significant amount of linolenic acid (7%) in addition to oleic and linoleic acids. Because of the high level of polyunsaturates, soybean oil is usually partially hydrogenated to prevent flavor reversion due to oxidation. It has seen extended use in the food industry in vegetable shortenings, margarines and salad dressings.

  Cottonseed, peanut, corn, sunflower, safflower, olive and canola are all part of the oleic-linoleic group. Rapeseed is part of the erucic acid group. In the development of canola from rapeseed, the erucic acid was replaced by oleic, placing canola within the oleic-linoleic group. The oils of this group consist predominantly of unsaturated fatty acids, primarily oleic and linoleic. Usually less than 20% of the oil consists of saturated acids. Linoleic and more unsaturated acids are usually present in low quantities, which results in more stable oils. Canola (low-erucic rapeseed) has very low levels of saturated fatty acids (6%) and a relatively high level of monounsaturated fatty acids (58%). It also contains a relatively high level of linolenic (10%), so canola oil has typically been partially hydrogenated to stabilize against oxidation.

  Sunflower normally contains relatively high levels of linoleic acid (78%), so natural sunflower oil would need to be partially hydrogenated for the purpose of frying, as would safflower, which normally contains about 78% linoleic.

  Cottonseed contains about 27% saturated fatty acids and about 54% linoleic. It has always been regarded as a relatively stable frying oil. Cottonseed has a characteristic buttery flavor and is often blended with other oils for use in mayonnaise, salad dressings and shortenings.

  Peanut oil has a slightly higher level of saturated fatty acids than soybean, with a lower level of linoleic, trace linolenic, and about 48% monounsaturates. This translates to an oil fairly stable to oxidation. Olive oil is also more resistant to oxidation because it contains a high level of oleic, relatively low levels of linoleic and linolenic, and about 14% saturated fatty acids.

  Corn oil is starting to receive more attention in terms of the potential growing of high-oil corn crops. The oil contains 69% linoleic, about 13% saturated fatty acids, and trace linolenic. DuPont has done some work with a high-oleic variety as an alternative to other high-oleic oils currently on the market.

  The base oils have offered some opportunity to blend for needed functionality, and processors have taken advantage of some of their unique properties. As Frank Flider, an independent consultant who represents the American Soybean Board, relates, "All oils have a place, and individual points of identity, any of which may be usable for certain functionalities."

  It is well known that fats and oils are very diverse because a number of factors can affect their physical structure and functionality. The possibilities are limitless. As mentioned, the degree of unsaturation can affect the physical state (oil or solid fat), and the extent of unsaturation affects stability and the "healthiness" of the oil. The isomeric forms and the chain length of the fatty acids present also have a profound impact on the melting characteristics of the resulting triglyceride. It is not the degree of unsaturation alone that determines the physical state at various temperatures. To further complicate the mix, solidified fats are polymorphic; several crystal forms exist, all with different melting characteristics. Finally, the molecular configuration of fatty acids on the glycerol backbone, as well as the extent of the mixture of triglycerides present, will affect the melting characteristics of the fat. The purer the triglyceride mixture, the sharper the melting point range.

Property-Enhanced Oils

  It takes a "long-term commitment to work with customers to design oils with certain fatty acid profiles for specific purposes and with certain nutritional properties," says Richard Thesing, director of product development and technical support for AC HUMKO Corp., Memphis, TN. "We are in it for the long haul to provide what we like to call property-enhanced oils."

  AC HUMKO's approach represents one of the methods used to design a new oil -- working with a plant breeder (in this case, Pioneer Hybrid) to obtain new properties via traditional cross-breeding. David Shockley, senior manager of technical service for AC HUMKO, points out that this is not entirely new: "In the late '70s, high-erucic rapeseed was cross-bred to produce a low-erucic variety now known as canola oil."

  Crop breeding has been used for a number of years, primarily to increase grower yield and the quality of the crops. What Thesing refers to as "identity preservation" is very important to maintaining the qualities of a new oil stock. This work has resulted in the successful development of canola as we now know it, as well as high-oleic sunflower oil and a high-oleic safflower oil. Now available are high-stability, "healthy" oils such as a low-linolenic soybean and a high-oleic/low-linolenic canola oil.

  And the development does not stop there. At the 1996 AACC (American Association of Cereal Chemists) meeting in Baltimore, Susan Knowles, research biologist at DuPont, presented a high-oleic (85%)/low-linoleic (2%)/low-linolenic (3%) soybean oil with improved oxidative and heat stability. Knowles noted that "high-oleic soybean oil showed greater oxidative stability than other high-oleic oils, including sunflower, canola and corn." Knowles and her co-workers have also studied the high-oleic corn oil previously mentioned, adding a new level of functionality to yet another source oil.

  Also on the horizon (in development) is a high-stearate soybean oil, which could be used in foods without hydrogenation. Studies have suggested that stearic acid is neutral with respect to effects on coronary heart disease (CHD). The objective in all of these cases is to improve the health and stability aspects of the oil. Oleic acid (18:1), a monounsaturate, can provide more stability than the polyunsaturates linoleic (18:2) and linolenic (18:3). From a health aspect, the higher monounsaturates are also preferred.

  Tony Del Vecchio, vice president, commercialization at Calgene, Davis, CA, has another approach: the development of structured fats through genetic engineering (see sidebar). Del Vecchio notes, "Our basic thrust has been to develop new oils, based on canola, that specifically meet certain needs of the food industry in a focused manner."

  Calgene has produced a transgenic canola oil that contains 38% lauric acid (12 carbons, no double bonds, melt point 44.2°C), designed as a cocoa butter replacer in confectionery coatings and as a principal fat in dairy systems. Says Del Vecchio, "What we have achieved with this fat is a functional alternative to imported laurics. That allows us to benefit from a more stable supply environment, hence a more stable pricing scenario that is not subject to the swings normally associated with the alternative tropicals."

  The future of this approach holds promise equal to the breeding approach. Del Vecchio foresees "transgenic canola fats with higher levels of laurate, high-stearate canola to replace the need for hydrogenation, and high medium chain fatty acid-containing canola targeted toward the health and nutrition markets."

  Of course, the positive side of all of this is that we can have healthful and stable oils that are tailored to provide specific, targeted functions. Over time, considerable expertise has been developed in plant breeding and transgenics. The problems encountered involve time, cost, and applications knowledge. Although regulatory concerns are not overwhelming, crop breeding (whether classical or transgenic) requires time. Time often increases cost of development. Also, notes Shockley, "Farmers charge a grower's premium to plant new varieties, and additional acreage is required to prevent cross-pollination with other crops."

  Whenever Del Vecchio, Shockley or Thesing talk about crop breeding, they also strongly emphasize "identity preservation." What do they mean by this? Any new crop introduced has unique properties. Any degree of mixing with other crops would dramatically change the functionality of the oil. Growers need to commit to the crop and isolate it sufficiently to prevent cross-pollination. Great care and cooperation must be in place to ensure that the right seed is planted, no mixing occurs and, when harvested, the grain is not mixed in transport or elevators. Additional steps must be taken at the crushing plant to ensure that no mixing occurs. Finally, the same steps must be taken at the customer level.

  From start to finish, cooperation and commitment from seed to customer are of utmost importance.

  The transgenic route requires additional regulatory costs to confirm safety. The result, however, is that once the crops are in place, the costs rapidly recede, so the cost to the food processor is competitive. The cost of chemical modification will also decline as efficiencies increase, but the cost of manufacture will always be a part of the overall price.

  In addition, notes Del Vecchio, "Although we are providing specific structured triglycerides in a less heterogeneous form than typical food fats, and at competitive prices, the functionality of fats in foods is not understood on a molecular level. As we get closer to being able to design specific triglycerides through a combination of genetic engineering and classical plant breeding, we need to learn more about the specific physical properties of the various triglycerides created by the plant."

  In other words, although the designers of fats now have many options on their palette, there is no history to predict what specifically will happen when the paint is applied to the canvas. The food industry has learned that fats and oils can be chemically distinguished from one another by the relative amounts and positions of fatty acids on the triglyceride molecule, and that the types of fatty acids and their position on the molecule determine the chemical and physical behavior of the oil. This knowledge is based on a rather random distribution of the fatty acids, however.

  The application of relatively pure, planned triglycerides is new territory. Ingredient suppliers will need to focus on specific industry needs, then try to build a working knowledge of what ratios of what fatty acids, and in what specific positions on the molecule, will yield the fat that will best meet the target objectives. We have the mixed natural triglycerides that originally served these categories as a guide point, but the optimization of less random molecules will be a challenge.

Calories and Fat

  The group of designer fats with the most consumer consciousness at this time are the synthetically structured fats. In any discussion of fat substitutes, these hold the most interest because they are designed to look and act like fats, but they contribute fewer calories and less fat.

  Two approaches to this have been taken: 1) work from a glycerol backbone and attach planned ratios of long-chain (LC) saturated fatty acids with very low caloric density and shorter-chain (SC) fatty acids with slightly lower caloric density than LC fatty acids (caprenin, salatrim); or 2) attach fatty acids to a non-glycerol backbone in such a manner that the molecule is poorly absorbed in the body (olestra).

  Since the first method results in a triglyceride similar to what could be found in nature, the regulatory route is far shorter: Have it reviewed by an expert panel, file a GRAS petition, and commercialize. The second route is a little more complex. A full food additive petition is required and, due to the amount of fat that could potentially be replaced in the diet, approval will be on a category-by-category basis until there is an adequate comfort level with any potential side effects.

Healthy Snacks

  On April 22, 1996, Frito-Lay announced the test-market introduction of a line of low- and no-fat, calorie-reduced salty snacks made with olestra (trademarked Olean). The Max(tm) product line consists of a number of snack varieties in a test market that includes Cedar Rapids, IA; Grand Junction, CO; and Eau Claire, WI. A 1-oz. serving of Lays Max potato chips is fat free with only 75 calories, compared to 10 grams of fat and 150 calories for traditional potato chips. On Sept. 17, Procter & Gamble announced the launch of Fat-Free Pringles™ in Columbus, OH.

  "Olean is an innovative product developed over the last 25 years to meet a real public health need -- reducing fat and saturated fat in our diet," according to Gilbert S. Omenn, M.D., Ph.D., professor and dean of the School of Public Health and Community Medicine, University of Washington. "This is important for reducing risks of heart disease and certain cancers, and for reducing weight."

  What is olestra, and where can it be used? In general, olestra is a type of sucrose polyester. As opposed to the glycerol backbone of triglycerides, olestra has a sucrose backbone, to which six to eight long fatty acid chains have been added (70% of the molecules have eight long chains). Olestra is synthesized from sucrose and vegetable oil (cottonseed or soybean), and it has physical properties comparable to conventional fats used in savory snacks and crackers. The complexity of the molecule inhibits the activity of digestive enzymes required to break it down. Therefore, olestra passes through the body undigested, contributing no fat or calories to foods.

  On Jan. 24, 1996, the FDA approved olestra for use "in place of fats and oils in prepackaged ready-to-eat savory (i.e., salty or piquant, but not sweet) snacks. In such foods, the additive may be used in place of fats and oils for frying or baking, in dough conditioners, in sprays, in filling ingredients, or in flavors." (CPR 172.867c). The product must bear an informational statement that says, "This product contains olestra. Olestra may cause abdominal cramps and loose stools. Olestra inhibits the absorption of some vitamins and other nutrients. Vitamins A, D, E, and K have been added."

  Olestra's approval by the FDA did not come without cost -- nearly 30 years, 270 volumes of data, and more than 150 long- and short-term studies.

  The synthetic route to healthy fats is not easy. Other fat substitute projects have either stalled out or have been placed on hold as the olestra project has progressed. Cultor's Food Science Group, Groton, CT, is working with a mixture of fatty acid esters of sorbitol (Sorbestrin), which is reported to be a thermally stable, fryable fat substitute with a caloric content of 1.5 kcal/gram. This product is not available commercially, and its use will likely require a full Food Additive petition in the United States. Other potential fat substitutes based on the same idea -- fatty acid esters of novel backbones -- will face the same scrutiny (and expense), so we cannot expect any newcomers to this area in the foreseeable future.

Glycerol Backbones

  While the "ultimate fat substitute" -- heat-stable, fryable -- seems to be in the olestra-type class, other developers of fats have chosen a more limited route. Several companies have worked toward synthesizing carefully structured triglycerides with a glycerol backbone, viewing GRAS approval as a much faster route to regulatory acceptance. This is usually done through interesterification, a modification process that results in the rearrangement of the fatty acids of the triglyceride molecule. Through choices of starting materials (different oils or fats), catalysts and/or enzymes, and kinetics, this reaction can be more directed toward a relatively specific end product. This means that the choice of fatty acids involved, as well as their relative ratios, can be limited.

  Interesterification has been used for some time as a more randomized process to produce plastic fats from animal/vegetable fat blends for use in margarines. The first product commercialized under this grouping was Caprenin, a reduced-calorie designer fat consisting of three fatty acids: capryllic (eight carbon atoms, no double bonds), capric (10 carbon atoms, no double bonds), and behenic acid (22 carbons, no double bonds). Behenic acid is only partially absorbed by the body, and the medium-chain fatty acids have lower caloric densities than longer-chain fatty acids, resulting in a total caloric density for caprenin of 5 kcal/gram.

  Caprenin was commercialized by Procter & Gamble as a cocoa butter replacer and was launched in two products. Unfortunately, the product has difficult tempering characteristics and appears to increase serum cholesterol slightly, resulting in its withdrawal from the market.

Salatrim

  As caprenin was being tested, another family of restructured fats was being developed by Nabisco Foods Group, Parsippany, NJ. Salatrim, which is an acronym for short and long acyl triglyceride molecule, is a family of structured triglycerides based on the use of at least one short-chain fatty acid and at least one long-chain fatty acid (stearic, C-18). Salatrim triglycerides typically contain one to two stearic acids combined with specific ratios of short-chain fatty acids (acetic, C-2; propionic, C-3; and butyric, C-4). As with naturally occurring triglycerides, the properties of salatrim are dictated by the fatty acids used, as well as their position of the molecule.

  "Salatrim was developed to provide a reduced-calorie ingredient that would function well in low-moisture food systems," notes Rebecca Kosmark, senior food technologist for Cultor Food Science Group. The first product, trademarked Benefat 1, was developed to replace cocoa butter in confectionery applications. A GRAS petition was filed in December 1993 and was accepted for filing by FDA in June 1994. Safety studies have shown no effect on serum cholesterol, no effect on absorption of fat-soluble vitamins, and have verified the safety of the molecule.

  Salatrim is the generic name for this class of molecules, and it is the name used on an ingredient legend. Due to the lower caloric density of stearic acid and the short-chain fatty acids, salatrim contributes a total of 5 kcal/gram. There are no regulatory restrictions on the category use of salatrim, but Nabisco interests have excluded its use (in North America only) in cookies, brownies, crackers, salty and savory snacks, and vegetable oil spreads through 1999. Other interests have restricted its use in deposited retail baking chips (Hershey's Reduced Fat Baking Chips), refrigerated cookie dough, and baking mixes through 1996.

  The Hershey's Reduced Fat Baking Chips claim "50% less fat" on the front panel, but the total fat on the Nutrition Facts panel reflects the total amount of fat in the product (including salatrim). A footnote says that salatrim is partially digestible, explaining the front label claim. A similar labeling approach was taken by Nabisco on a Snackwell's coated granola bar recently launched.

  Since the FDA has no regulation for food factors regarding fat reduction (only calories), these claims have resulted in some controversy and discussion at FDA. No action was taken on these label claims, and the FDA is gathering information to provide a final ruling. In its 1994 petition, Nabisco claimed that, since five-ninths of the fat available in salatrim was used by the body, the product would have a food factor of 5/9 -- related to both fat and calories.

Medium-Chain Triglycerides

  The concept of structured fats has been around for a number of years. Medium-chain triglycerides have long been recognized for their nutraceutical potential; their major drawback may be education of the consumer. Medium-chain triglycerides (MCT, C6 - C12) are metabolized differently than long-chain triglycerides (LCT, C14 - C24). LCTs are hydrolyzed, then re-esterified to triglycerides, then imported into chylomicrons, which enter the lymphatic system. MCTs bypass the lymphatic system. They are hydrolyzed to MC fatty acids, which are transported via the portal vein directly to the liver, where they are oxidized for energy. They are not likely to be stored in adipose tissue. For enteral and parenteral feeding, their advantage is already known. MCTs provide patients with an energy source similar to glucose, but with twice the caloric value.

  In June 1994, FDA accepted for filing a GRAS petition from Stepan Food Ingredients, Maywood, NJ, covering captrin "structured" triglycerides. Captrin is the proposed common name for a group of MCTs that use chain lengths of C8 - C10. Their primary use at this time is as flavor carriers for fat-free food products. A first line of products is based on interesterification of butter oil and MCTs.

Back to Trans

  While others have concentrated on chemical modification of triglycerides to lower calories and fat in the diet, two scientists from Brandeis University in Waltham, MA, set out to design a saturated fat that would perform like tallow, lard or butter without raising serum cholesterol. Initially, the goal was to study the nutritional impact of animal fats in the absence of cholesterol as part of a major study on the characteristics of a large number of fats and fat blends.

  Brandeis worked with Source Food Technology, Minneapolis, to steam-strip cholesterol from animal fats. (Source Food Technology had developed this technology earlier.) The research led to the commercial development (with Bunge Foods, Bradley, IL, which licensed the product in 1994) of Appetize, a family of modified fats made from vegetable oil and cholesterol-stripped animal fats. These products, now commercialized, contain no trans fatty acids. Studies show that diets with Appetize fats result in lower total cholesterol levels compared with diets high in saturates. The USDA has approved the terms "modified beef fat or lard" and "distilled beef fat or lard" for labeling purposes.

  Although other forms are possible, Appetize is currently available as a frying product (modified beef fat, corn oil, TBHQ, citric acid, dimethypolysiloxane); a lard product for pie crusts and general baking (modified lard, corn oil, partially hydrogenated lard); and a tallow product for general baking (modified beef fat, corn oil, partially hydrogenated beef fat). Appetize fats are still high in saturates, but with no trans or cholesterol, and they are priced to be competitive with vegetable oils.

New Directions

  Although successes have been achieved recently in what are termed "structured fats," these have not come without considerable time and cost. The laborious process of developing an olestra-like product will prevent most ingredient suppliers from exploring that route. New developments will be focused on those categories that will bear the cost. Plant breeders and genetics experts need to be somewhat clairvoyant, and they must work closely with end-users to anticipate markets several years away.

  Because soybean oil has the largest share of the edible oil market, its price is relatively low. So, much recent breeding and transgenic activity has centered around soybean. Interest has increased toward the "healthy" oils (canola, sunflower, safflower and olive oils), and this will probably continue. Within these oils, as suitable substitutes are found for other high-saturated fats (or fats with less predictable crop stability), their use will decrease.

  Says Del Vecchio, "Food processors continue to look for functional and safe ingredients at competitive prices. They also continue to rely on food ingredient manufacturers to supply new technology-infused ingredients that will allow them to deliver new and improved forms of products to their customers."


  Ronald C. Deis, Ph.D. is a food scientist with 17 years in the food industry, both in product development of consumer goods and technical service for ingredients for the food industry. Among other products, he has worked extensively with fat and sucrose replacers and reduced-calorie ingredients.

<

Hide comments
account-default-image

Comments

  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Publish