Baking Sans Trans

By Cindy Hazen, Contributing Editor

For the last few years, the food industry has had an image problem. Congress is pressing for increased food-safety legislation; consumers are skeptically eyeing ingredient labels; and consumers are turning to locally grown and produced foods. In my town, that includes buying home-baked goods from neighbors. It seems that trust lies heaviest where there is zero regulation.

At last the industry has some good news, at least in the realm of healthier fats. A recent study failed to validate this consumer mistrust. The Center for Science in the Public Interest (CSPI), affectionately known as the food police, collaborated with Harvard researchers to see if food manufacturers have simply replaced trans fats with potentially "bad" saturated fats. The results, published in the May 27 issue of the New England Journal of Medicine, (362(21):2,037-2,039) found that after reformulation, almost all of the 83 brand-name packaged and restaurant foods had lower amounts of trans and saturated fatty acids than their earlier counterparts. The researchers concluded that the industry has met the trans challenge by producing heart-healthier foods.

There is still room for improvement, though. Some foods have faced a more-difficult transition than others, including baked goods.

The road less trans

The journey to zero-trans baked goods is full of challenges. The history of baked goodsand most of our standardswere originally created using fats that were available at the time and provided certain properties. These were of animal origin, including butter, tallow and lard. They have a creamy texture, and they are semisolid at room temperature due to the presence of saturated fat, says Gerald McNeill, Ph.D., vice president, R&D, Loders Croklaan USA, Channahon, IL. They have a small crystal size that promotes air entrapment in dough and gives a smooth texture. Due to the presence of very low levels of polyunsaturated fat, they have a very long shelf life and do not easily develop off flavors.

When liquid vegetable oils were first available in large quantities about a century ago, it was quickly recognized that they did not have the functionality needed for baked goods. The process of hydrogenation was invented to convert the liquid oil to a semisolid with a low level of polyunsaturates. In addition to an increase in saturates, a byproduct called trans fat was also formed. The trans fat is also solid and contributes to a smooth, creamy texture, says McNeill.

The key components that define a shortening or margarine are the ratio of saturates to unsaturates and the manner of crystallizing the blend of saturates and unsaturates into the desired plastic shortening or bakery margarine. Cookies, biscuits and pie doughs are typically formulated with all-purpose shortenings, says Roger Daniels, director, R&D and new business development, Bunge Oils, Bunge North America, Bradley, IL. This ingredient class typically has melting points in the 115° to 120°F range and a solid-fat content slope which is relatively flat. These two attributes yield a dough with a workable texture and consistency over a wide range of temperatures.

Bakery fats require an optimal level of plasticity for functionality. Among other things, they need to be pliable with the correct degree of firmness, notes Larry Skogerson, Ph.D., vice president, R&D, Caravan Ingredients, Lenexa, KS. For example, a roll-in margarine for puff pastry will be firmer than a roll-in for Danish. Plasticity is achieved by a combination of the right level of solid and liquid fats, combined by passing the oil mixture through a scraped-surface heat exchanger, a process commonly referred to as votation. In addition, the level of solids should not be so high that the fat will have a waxy eating quality. Partially hydrogenated fats contain the trans fatty acid elaidic acid, the 9-trans isomer of oleic acid. (C18:1) Elaidic acid has a melting point of about 40°C that is ideal for bakery fats since it provides structure at ambient temperatures, but will melt in the mouth. Unfortunately, the body does not metabolize elaidic acid in a normal way and it is not, therefore, desired for use in food from a nutritional perspective. Partially hydrogenated fats also contain a wide variety of fats with different melting points, and the combination contributes to a desirable solid-fat content curve.

Successfully replacing these fats requires the ability to maintain two criteria. The fats must be naturally semisolid at room temperaturetherefore, it follows they will also contain saturated fat. Secondly, they must possess a long shelf life, meaning they must contain a low level of polyunsaturates. The original animal fats (butter, tallow and lard) work well in many applications, but in addition to their saturated-fat content, there are several new barriers to their use, says McNeill. Butter is relatively expensive, and animal fats in general are not preferred due to the need for kosher status by large food manufacturers. Another problem is the need to match the wide variety of textures that different hydrogenated fats provide.

Shelf life is a significant issue when replacing trans-rich fats. With the development of high-oleic oils, some shelf-life challenges may be overcome, says Tom Tiffany, senior technical sales manager, ADM Oils and Fats, Decatur, IL.

When using nonhydrogenated oils, manufacturers may also face production challenges. Tiffany finds that, in certain applications, low-trans alternatives do not crystallize as quickly as high-trans products. Therefore, dough may be softer and more difficult to process, such as sticking to rollers, tearing, etc., he says. On the other hand, if the low-trans product crystallizes too quickly or contains too many solids, the dough can become stiff and lack the resiliency needed for movement through dough-handling equipment.

Drop-in solutions

According to Daniels: The shortening and margarine manufacturers have invested in three basic approaches to ensure that reduced-trans shortenings and margarines are drop-in replacements to traditional shortening and margarines for use in bakery products. Specifically, special hydrogenation technology, an expanded base-oils range and enzymatic interesterification are now employed.

Relative to special hydrogenation technology, notes Daniels, "scientists from Bunge Oils discovered a means to partially hydrogenate soybean oil such that trans formation is severely limited, resulting in a functional shortening and margarine base with a reduction in trans by greater than 85%, he says.

Manufacturers can also augment many base oils, such as traditional soybean and canola oils, with palm oil, fractions of palm oil and high-oleic canola oil. This results in functional shortening and margarine ingredients that do not employ hydrogenation.

In the vast majority of cases, palm-oil blends can be used as a drop-in solution to replace any partially hydrogenated fat, says McNeill. In most cases, no changes in ingredients or formulas are required. For example, simple palm-oil fraction blends provide excellent all-purpose shortenings for standard products, such as many types of cookies, doughnut frying, microwave popcorn, pie shells and pizza. Laminated products such as croissants, Danish and flaky pastries are more challenging. The fat must be very smooth and flexible over a wide range of temperatures to avoid creating holes or tearing the dough. Again, blends of palm-oil fractions have been developed that match the corresponding hydrogenated-fat products without the need to change formulas.

Shortenings and spray-oil options have been derived from omega-9 (oleic acid) canola oil. These are ideal for food manufacturers looking to eliminate trans fat and reduce saturated fat without compromising food quality, functionality or performance, says David Dzisiak, commercial leader oils, Dow AgroSciences, Indianapolis.

Unlike shortenings typically high in saturated fat, omega-9 shortening can offer zero trans fat, significantly reduce the amount of saturated fat and add more heart-healthy monounsaturated fats to recipes, resulting in healthier nutrition labels and cleaner ingredient panels, says Dzisiak. Omega-9 shortening is naturally stable and can provide equal or longer shelf life compared to products containing traditional, high-saturated-fat shortenings. This can be achieved without the use of antioxidants or tertiary butylhydroquinone (TBHQ), preserving a cleaner product label that consumers demand.

However, Dzisiak cautions that moving to a zero-trans shortening is not a simple drop-in solution, because these products require a significant amount of formulation research and development to ensure the product retains the properties customers have come to expect. It can be helpful for food developers to work with their suppliers for formulation assistance and analytical support.

Omega-9 shortening can be used in just about every bakery product on the market, says Dzisiak. Replacing partially hydrogenated oil in a muffin with omega-9 shortening can significantly reduce the saturated fat, he says. Baked goods that utilize a palm-oil spray topping, such as butter-topped bread, can also be reformulated with an omega-9 shortening to create a significantly healthier profile.

Another trans-reducing strategy is interesterification, which involves rearrangement of fatty acids on the glycerol backbone. This allows the oil processor to selectively create different triglycerides based on desired functionality of the shortening and oils.

Tiffany notes that enzymatically interesterified shortenings and margarines utilizing soybean oil and fully hydrogenated soybean oil tend to be rich in stearic, omega-6 and omega-3 (alpha-linolenic) fatty acids. The American Heart Association has indicated that stearic acid may lower blood cholesterol. When soybean oil is used as the liquid portion of the blend, the levels of omega-3 and omega-6 fatty acids are also increased compared to palm oil or partially hydrogenated vegetable oils used for similar applications.

ADM has received notification from FDA that when foods are formulated with interesterified soybean oil, the descriptor of interesterified soybean oil can be used in the ingredient statement. Interesterified products have been shown to work well in a variety of applications, including cookies, cakes, Danish, icings and crackers.

Trans replacement in icings can be especially difficult. In this application, it is important to have a structure that is not too firm and not too soft. Partially hydrogenated vegetable shortenings with the correct emulsification system have met the functional and sensory demands for icing applications for many years, says Tiffany. He recommends using interesterified soybean oil in icings.

Skogerson suggests an alternative way to provide structure to oils by using emulsifiers consisting of glyceride esters with specific ratios of mono-, di- and triglycerides. They work because the emulsifiers crystallize as very small beta-prime crystals, creating a very large surface area capable of absorbing a large volume of oil, he says. The emulsifier-structured oil has plastic properties sufficient for application in a wide variety of bakery products, from puff pastry to pie crust. The labeling of the emulsifier-structured oil shortenings would be oil and mono- and diglycerides. Saturated fat would be from 20% to 50% less than comparable shortenings made from palm and palm fractions.Using these structured oils requires no specific formula adjustments, he says.

Palm possibilities

McNeill believes that palm oil makes an ideal natural alternative to partially hydrogenated vegetable oil where a solid fat is required for functionality and stability in baked goods and snack foods. It is naturally solid at room temperature, and no chemical processes are used in its production.

Palm oil readily forms small fat crystalscalled beta-primeand these crystals impart a desirable smooth, creamy texture to the fat and the food products that contain them, says McNeill. The small crystals are highly effective in entrapping tiny air bubbles, which is essential to the creaming process in baked goods. Due to the low level of polyunsaturated fats and the presence of natural antioxidants, palm has excellent shelf life without the need for synthetic antioxidants. This functionality and stability, coupled with a low cost, makes palm oil a popular choice for the elimination of trans fat in the bakery industry.

However, Skogerson finds palm fats crystallize slowly in some cases, creating difficulties for the shortening or margarine manufacturer. In other cases, the slow crystallization of the palm fats causes the plasticity to decrease over a period of one to three months, decreasing the functionality of the product. The basic challenge is to provide stable plasticity over the shelf life of the product. Palm contains mixtures of solid and liquid fats that provide some plasticity, and this can be enhanced with the use of palm fractions that have certain structuring characteristics, he says.

A physical process called fractionation squeezes a liquid component, palm olein, from the palm oil in high-pressure filters. Left behind is a hard, waxy component called palm stearin (stearine), says McNeill. These fractions can be further fractionated and blended together in different proportions, resulting in many products with differing physical properties. Palm stearins are available in a wide range of melting points and iodine values (a measure of the oil stability). Due to the process of fractionation, palm oil offers an almost unlimited variety of different functionalities and applications, he continues. Food products requiring a reduced saturated-fat content can again turn to palm oil, by blending it with liquid vegetable oils.

Saturates vs. trans

Although palm oil is sometimes referred to as a saturated fat, McNeill says that it is, in fact, a natural balance of unsaturated and saturated fat, containing an equal amount of saturated and unsaturated fats. For each gram of saturates consumed, an equal amount of unsaturated fat is consumed. Regular palm oil contains 50% saturated fat, compared to 15% in soybean oil.

Plus, says McNeill, recently, several large nutrition studies have shown that saturated fat is not as bad as once thought. Although it is known to raise cholesterol, it also raises good cholesterol (HDL), partially counteracting the bad cholesterol increase, he explains. Scientists are now considering that the saturated fat in palm oil (mainly palmitic acid, plus some stearic acid) may have a  neutral net effect, neither increasing nor decreasing risk of heart disease. But trans fat present in hydrogenated oils decreases good cholesterol, making saturated fat a healthy alternative.

McNeill suggests that its important to realize that although a baked goods nutrition label may list zero grams of trans fat, it may still contribute to risk of heart disease if the ingredient statement lists partially hydrogenated vegetable oil.  When the trans fat content is less than 0.5 grams per serving (0.49 grams or less) it can be labeled 0 grams, he says. However, the American Heart Association recommends a trans fat intake of less than 1% of the dietthats about 2 grams per day. Eating four 0-gram servings of food could reach that limit, but the consumer will not be aware of it. Palm oil only contains trace amounts of trans fat.

A multidisciplinary panel of nutrition and clinical experts met in 2008 to evaluate trans-fat replacement solutions. The panelists concluded that, when possible, trans fats should be replaced with a polyunsaturated or monounsaturated fat. However, when a saturated fat is needed for functionality, it can be expected that overall cardiovascular-disease risk would be improved compared to trans fats.

Saturated-fat options to replace a sold fat include palm oil or interesterified stearic acid. Replacing trans fats with either palmitic acid or interesterified stearic acid is expected to reduce cardiovascular risk factors.

Clearly, the industry has developed options that meet the trans challenge in baked goods, reformulating for heart health, saturates and all.

Cindy Hazen, a 20-year veteran of the food industry, is a freelance writer based in Memphis, TN. She can be reached at [email protected].