March 31, 2005

Methods and Opportunities for Reducing
or Eliminating Trans Fats in Foods

Executive Summary

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Companion Presentation also available

Introduction:

For some time, Canadians have been learning about the health implications of trans fatty acids produced industrially during oil refining.  Trans fatty acids have been implicated as increasing levels of LDL-cholesterol and lowering the beneficial levels of HDL-cholesterol in the blood.  A decrease in the consumption of trans fatty acids is being identified as important to lowering the risk of coronary heart disease.  Some experts argue that, gram for gram, trans fatty acids pose a greater risk of coronary heart disease than do saturated fatty acids.
 
The report presented here was commissioned by Agriculture and Agri-Food Canada to Stewart J. Campbell of S.J. Campbell Investments Ltd. in early 2005 to review the methods available to reduce or eliminate trans fats in foods. The report considers alternatives to trans fats and possible innovations that might help Canada achieve the objective.  The end result is an analysis, from a technological point of view, as to how ready the Canadian industry is to deal with the possibility of a reduction or elimination of industrially produced trans fatty acids from the Canadian food supply.

Main Players to Address the Issue

The objective to reduce trans fatty acids in foods involves three main players, with differing roles and responsibilities.  The challenge is to align the interests and activities of these players with the public health objective.

1. Food Industry
   • Requires changes in manufacturing practices.
   • Requires resources to develop innovative processes and products.
2. Consumers
   • Be aware of food product choices.
   • Choose healthy foods and lifestyles.
3. Governments
   • Be certain of the science, and the intervention strategy.
   • Understand the impacts of any changes implemented.
   • Guide - via regulation, by example, by inducement.
   • Communicate a credible and consistent message.

Properties of Oils and Fats

Oils and fats are the primary source of energy for the body.  They are also carriers of flavor and vitamin compounds and contributors to the mouthfeel of food.  In manufacturing food, fats perform as a heat transfer medium, lubricant, release agent and texturizing agent.  These sensory, functional and nutritional properties of fats and oils are determined by the levels of palmitic (C16:0) and stearic (C18:0) saturated fatty acids, oleic (C18:1) monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA) and trans fatty acids.

The melting characteristics of fats determine their usefulness in food products, both in terms of their behavior during processing and during consumption.  Increasing the level of saturation increases the melting point of fats, and converts liquid oils into plastic semi-solids or solid fats.  Saturated fats are about 10 times more stable than monounsaturated oils and fats, 100 times more stable than di-unsaturates, and 1000 times more stable than tri-unsaturates.

Occurrence of Trans Fatty Acids in Foods

Trans fatty acids originate primarily from partially hydrogenated vegetable oils.  However, 3 - 8% of the fatty acids in butter, cheese, milk, beef and mutton can also be trans.  The latter are produced naturally in animals by the enzymatic hydrogenation of unsaturated fats.  
The North American edible oil industry including Canadian firms have made significant progress towards reducing the trans fat contents of foods.  Many brand owners are marketing low/zero trans in established and new products.  However, the inspection of food labels suggests that the trans fatty content of hard margarines and some other foods may still be problematic, with some labels declaring ~35% trans fatty acid content in the fat.

Trans Fat Reduction Methods Available to the Industry

There are three main approaches that can be used to reduce or eliminate trans fats in food:

1. Customization of Crop Varieties
   • Mutation and transgenic technologies provide the possibility for plant breeders to incorporate a range of fatty acid profiles that are different to the composition of the normal (original) oil in many oilseed species (see Figure I).

Figure I. Fatty Acid Composition of Vegetable Oils

• Work by Warner et al ¹ has shown that salad and frying oils are more stable with moderate levels of oleic acid (< 80%) and low linolenic acid (< 3%). In addition, saturated fatty acids were recommended to be low (<7-8%) and linoleic acid at least 20-30%. Oils with this profile should have sufficient oxidative stability for use in many salad, frying and spray oil applications and not need light hydrogenation. By avoiding hydrogenation, trans and saturate fatty acid levels are not increased.
  
  
• Low linolenic high oleic canola oil genotypes with less than 3% linolenic acid are already in commercial production in Canada.  The present varieties however are lower yielding than canola varieties with normal fatty acid composition.  This is due to the relatively lower investment that has been made over the past 15 years to breed low linolenic varieties and the fewer generations of plant improvement compared to those with normal fatty acid composition.  Low linolenic genotypes in soybean are in the early stages of commercialization in the US.
  
  
• With the superior quality and expanding demand for low linolenic genotypes for food manufacturing and food service, the Canadian plant biotechnology industry might be expected to increase its investment in breeding for low linolenic genotypes adapted for Canada.  The industry might also consider investing to develop high stearic genotypes targeted for the solid fat markets.  Both types of oils should reduce the need for hydrogenation and resulting production of trans fatty acids.  However, the high stearic genotypes are synonymous with high saturates.
  
  
2. Modification of Fatty Acid Composition by Processing
   There are six main processing techniques available to the edible oil industry to reduce trans fatty acids as the chemical and physical of oils and fats are modified for food use.

Hydrogenation - mature technology, current practice of the industry.

• For products needing the melting properties of a partially hydrogenated basestock, zero trans is not likely to be possible with light hydrogenation.
• For products that must have the melting characteristics of a plastic or solid fat, complete hydrogenation of a canola or soybean oil will result in a zero trans stearine fat which is almost 100% saturated. 

Blending of basestocks - mature technology, current practice.

• Zero or low trans can be produced by blending various basestocks.
• Difficult to get the desired melting properties in the plastic blended fat.

Fractionation - mature technology, with some potential for more use in Canada.

• Widely used in palm oil processing in other countries.  Results in unsaturated palm olein and saturated palm fractions with useful melting properties.
• Process has been demonstrated with experimental high stearic soybean oil.

Use of Saturated Fats - mature technology, but limited alternatives for Canada.

• Domestic - fully hydrogenated canola and soybean C18:0 stearine.
• Domestic - animal fats - tallow and lard.
• Imported - tropical oils and fats - palm, coconut, babasu, etc.

Chemical Interesterification - mature but improving technology.

• Proven track record in Europe and some use in US and Canada.
• Range of consistencies and melting properties possible for zero or low trans margarine, shortening and confectionary fats.

Enzyme-assisted Interesterification - emerging technology, with great potential.

• Enzymes can be highly specific, providing for more control of the reaction and lower processing temperatures than chemical catalysis. 
• LipolaseTM - produced by Novozyme A/S by fermentation of an Apergillus orzyae strain genetically modified with a Thermomyces lanuginosus lipase gene.
• Economics of interesterification improved greatly with immobilization and reuse of the Lipolase enzyme.
• Novozyme / De Smet now marketing a low trans process with lower capital and operating costs than hydrogenation and chemical interesterification.
• Food Reformulation

One strategy for reducing trans fatty acids is to decrease the overall fat content in foods.  Fat replacement will become very important if it is determined that the levels of saturated fats should not increase as trans fats are reduced.  With few exceptions, fat replacement will require product reformulation in order to achieve the desired properties in the processed food.

Fat replacers are ingredients which mimic the functionality and sensory properties of fat, but contribute fewer calories.  Selection of suitable fat replacers requires a solid understanding of the food system in question and careful weighing of the advantages and disadvantages of each product.  In many cases, a blend of ingredients offers the best solution for fat reduction.  It is worthy to note that some food ingredients that might be useful as fat replacers are not approved for use in Canada.

Initiatives to Reduce Trans Fatty Acids In Foods

1. Investment

   Solutions to reduce trans fatty acids in foods will require investment for replacement technologies and development of new processes and products.  These avenues call for public and private investment in R&D, technology transfer and demonstration, and capital investment.  For each product, there are choices to be made whether the technical solution should be made in Canada or purchased from abroad.  When considering public investment in R&D, it is suggested that public funds are best applied where the R&D provides the Canadian industry with lasting competitive advantage. 

2. Public Awareness and Education - Fats & Oils

   While the public is increasingly aware of trans fats, it is perhaps not sufficiently aware of the range of nutritional choices available and that many foods require the physical and chemical properties provided at present by saturated or trans fats.  It appears there may be need of more public education about saturated fats - and that these might be nutritionally acceptable or at least tolerated at some level in some foods.

3. Health Benefits of Low / Zero Trans Fat Products

   Many of the techniques being adopted by the industry to replace trans fats rely on the increased use of palmitic and stearic saturated fatty acids.  Validation of the nutritional merits of these new palmitic and stearic saturated fat formulations as replacements for trans fatty acid formulations seems warranted.
   
   While trans fats are a hot topic today, most trans mitigation strategies being implemented do not reduce caloric intake.  It has been suggested that obesity mitigation could be a bigger issue for everyone to deal with than trans fat mitigation.

4. Change the Composition of Oils and Fats - Timeframe
   
   Retail salad & cooking oils, salad dressings
   • Native canola, soybean & sunflower oils are naturally in low trans fats.
   • Very small amounts of trans fat produced during deodorization.
   • Additional trans fat if, for example, soybean oil is lightly hydrogenated.
   • Low linolenic canola oil is available today, but has no marketing advantage in Canada to normal canola salad oil when sold as a retail packaged salad oil.
     
     
   Margarines and spreads
   • Soft margarines - low trans available today.  Low trans soft margarine products exhibit a wide range of polyunsaturated fatty acid content.
   • Hard margarines - still high trans fat.  Low trans possible if processors ignore functionality and cost.  New products possible in a 1 - 3 year timeframe, but likely to contain high levels of saturated C16:0 and/or C18:0 fatty acids.
     
     
   Frying oil - food service and quick service
   • Heavy duty frying requires stable fats.
   • Low linolenic / high oleic canola & sunflower being adopted, but at higher cost and some reduced functionality /sensory properties.
   • Low linolenic soybean entering US pipeline.  A Dupont high oleic soybean trait has been approved in Canada.
   • 1 - 3 years for product development with existing oils.
   • 4 - 8 years for low linolenic soybean oil, if pursued by the industry.
     
     
   Industrial frying and food processing.
   • Low linolenic / high oleic canola and sunflower available today for snack frying, with acceptable functionality and sensory properties.
   • Potato chips, tortilla chips, frozen french fries, etc. converting to low trans.  See USDA 2004 report confirming the progress. 
   • Doughnut frying and spray oils - still a challenge for functionality.
   • 1 - 3 years for product development with existing oils.
   • 4 - 8 years for low linolenic soybean oil, if pursued by the industry.
     
     
   Baking shortenings.
   • Wide range of food product specific functionalities required.
   • Melting characteristics of the plastic fats critical and tied to the trans and saturate fat contents of the basestocks.
   • Fractionated and interesterified fractions are possible replacements for trans.
   • Formulation challenge to develop zero or low trans replacements for all purpose shortening, emulsified shortenings, and pastry roll-ins where specific functionalities required.

Innovation Opportunities

1. Fat Replacement in Foods
   
   There are numerous opportunities in developing fat replacers for specific fat functionalities.  Many approaches are available to mimic fats and achieve the lubricity, smooth texture, and mouthfeel characteristic of traditional high fat products.  As trans fatty acids are often needed to achieve the required functionality in bakery products, the use of emulsifiers to reduce or eliminate fat in the formulation will result in reduced trans content. ²   Danisco has identified the use of emulsifiers as a major strategy in the reduction of trans fatty acids in its products. 
   
   
   Other firms are investigating the use of emulsifiers as structuring agents to eliminate the need for saturated and trans fatty acids in typical hardstocks or in edible spreads. Essentially, these are gels which mimic the texture imparted by fats, and therefore can be used in the manufacture of low-fat or low-trans and low-saturates edible spreads.
   
   
2. Nutraceutical Lipids
   
   Structured lipids produced by interesterification are used in fat emulsions for total parenteral nutrition and enteral administration.  They can be designed to contain a desirable balance of short, medium and long chain fatty acids than meets a certain nutritional requirement.  Reduced calorie fats can also be produced because of differences in the absorption and physiological response of short, medium, and long chain triacylglycerides (TAGs)
   . 
   
3. Membrane Technologies
   
   The recent advances in membrane technology may provide opportunities for using membrane reactors to immobilize highly specific and fast homogeneous catalysts.  This would solve the problem of separating and recovering the oil-soluble catalysts from the reaction mixture.  Membrane processes have not been explored commercially by edible oil processors, primarily because many of the processes require that the oil be present as a solution in a solvent (for example hexane), and earlier membranes were not resistant to hexane.  (Oil is recovered from the seed as a hexane solution, which is called miscella). 
   
   
4. Novel Hydrogenation
   
   Electrochemical approaches to hydrogenation have been proposed.  One method employs a solid polymer electrolyte (SPE) reactor, similar to that used in H2/O2 fuel cells.³ Hydrogenated soybean oil products had a low percentage of total trans isomers (4 ­- 10%).  A preliminary economic analysis of the SPE reactor apparatus suggested the method might be cost-competitive with traditional oil hydrogenation schemes, and commercial-grade products could be prepared by blending low trans, electrochemically hydrogenated oils.
   
   Enzymatic hydrogenation might also be considered using enzymes and pathways such as used by rumen microorganisms to produce oils of varying degrees of unsaturation. ⁴
   
   
5. New Types of Food Products
   
   There are numerous alternatives for the heat treatment of food products, such as extrusion. These processes are fundamentally different from traditional cooking, frying and baking, and will result in products that are completely different from traditional food products.  Combination of different unit operations might be used to develop products that reproduce some or all of the functions of traditional products, and can lead to many new unique food products.  Rapid development of these technologies requires a better fundamental understanding of the kinetics of underlying processes.

Conclusions

Reducing or eliminating trans fats will be transforming for the Canadian as well as the global food industry.  There are no drop-in solutions that can easily be applied at just one level of the industry in order to effect total change.  The transformational change needed is systemic and requires a variety of technical solutions, many players and the support of consumers. 

The industry has made considerable progress to reduce trans fats in many products, and is striving to bring forward zero or low trans fat solutions for all food products.  The remaining challenges are surmountable with investment, time and learning.

It is significant that the leading technologies result from the convergence of mutation and transgenic plant breeding, innovative process engineering and the latest in food science and product formulation.  Some of the basic nutrition research and plant breeding supporting the solutions that are being advanced have been under study for as long as 30 years.  The investment in plant breeding has been significant, initially by public institutions, and commencing about 15 years ago, increasingly by industry in Canada and elsewhere.

Equally important, many of the core technologies beginning advanced appear to have commercial potentials for new products and new foods that might address issues far beyond the trans fats problem.  The long-term benefits of these innovations are possibly greater than those identified at present for trans fat mitigation.   




¹ Warner K., Neff W.E., Byrdwell W.C., Gardner H.W. Effect of oleic and linoleic acids on the production of deep-fried odor in heated triolein and triolinolein. J Agri Food Chem 49 :899 -905, 2001.

² Jay Sjerven . Targeting Trans Fats.  Baking & Snack, August 1, 2003.    http://www.bakemark.com/TargetingTransFats.htm

³ Hengbin Zhang, Maria Gil, Peter N. Pintauro, Kathleen Warner, William Neff, and Gary List.  The Electrochemical Hydrogenation of Soybean Oil with H2 Gas.  http://www.aocs.org/archives/am2000/am2000tp.asp

⁴ Loor, J. J., A. B. P. A. Bandara, and J. H. Herbein. 2002a. Characterization of 18:1 and 18:2 isomers produced during microbial biohydrogenation of unsaturated fatty acids from canola or soybean oil in the rumen of lactating cows. J. Anim. Phys. Anim. Nutr. 86:422-432.

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Date Modified: 2006-05-11		Important Notices
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