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Elimination of trans fats: Challenge for bakery industry
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Thursday, 02 January, 2020, 08 : 00 AM [IST]
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Dr Venkatachalapathy Natarajan and Nikitha Modupal
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1. Introduction
Shortening is an edible fat component added as one of the important ingredients in bakery goods such as cakes, doughnuts, bread and waffles. The major function of fats in the baking process is that they impart tenderness, aeration, moistness, flavour-binding and mouthfeel to the final product.
Fats also help in proper leavening, impart plasticity to batters and doughs which is essential for proper structure and geometry formation of goods. Most commonly used shortenings in baked goods are either animal fats like lard and butter or partially hydrogenated vegetable fats like margarine. These solid hard-stock fats contain higher amounts of trans-fats, which has become a growing concern among the consumers in recent times. The new intervention by FSSAI to limit the trans-fats to less than 2% in the entire Indian food chain by 2021, a year earlier to WHO target, has made a burning necessity for an immediate shift towards a healthier approach.
The limitation in usage of hard-stock fats and shortenings or replacing them with liquid oils without negatively impacting the organoleptic properties of the product is not possible. This raises the question for the possible alternative approaches to eliminating the trans-fats from the bakery industry. One of the effective solutions is the usage of structured oils and fats to replace conventional shortenings. The edible oil structuring a widely accepted strategy for elimination of trans-fats in the food systems. The term oil structuring refers to rheological structuring the edible liquid oil to form into a solid component by using various gelator components.
2. Structured edible oils
The structuring of edible oil refers to impart a solid body to the liquid oil, also called as oleogels meaning gels made from oils. It is a novel technology, in which entrapment of organic edible oils is done to create a thermo-reversible, three-dimensional gel network. This is achieved by complex assembly of various gelator molecules like proteins, lipids, polysaccharides such as starches and waxes, emulsifiers, minerals, water and few other minor compounds. The molecular interactions between these gelator molecules help to establish the mesoscopic structures like colloids, emulsions or gel fractal networks. The networks trap the oil inside and form oleogel, which is a macroscopic solid and microscopic liquid.
The development of such oleogels using food-grade ingredients is being quite extensively explored by the scientific community in the past decade. Lipid-based structurants like sterols, fatty acids and lecithin can be used to make oleogels, to make a viable substitute to butter without affecting the fatty acid profile of the final product. Ethyl cellulose-based oleogels can be used for low-temperature products, due to less oxidative stability of the oleogel.
Natural waxes like carnauba wax, rice bran wax, candelilla wax and sunflower wax can also be used to create wax-based oleogels, due to their bio-based structure, good availability and low cost.
Fatty acid derivatives such as sorbitans can produce weak, opaque thermo-reversible oleogels. Similarly, glycerol monostearate can also be used as a potential gelator, due to its hardening properties.
Oleogels were used to make cookies, which produced better-quality cookies that are consumer acceptable and low in trans-fats. Wax-based oleogels can be used in the preparation of shortbreads and cakes without dramatically altering the original integrity of the product. The oleogels were also used to produce cream fillings and sauces, that can help in reducing oil separation and to prolong shelf life. The usage of oleogels in meat products for improving the fatty acid profile is a novel idea, consisting of lean meats and added oleogels. These products can be effectively used as highly nutritious ingredients in preparation of fillings and sauces in puff pastries and baked pies.
3. Other functions of oleogels
Apart from providing an effective substitute to hard-stock fats, oleogels can be efficient nutrient carriers and can be used for encapsulation of high-value compounds like resveratrol, EPA, DHA and so on. Oleogels can also be used for delayed or targeted delivery of functional nutrients, nutraceuticals and viable drugs, that makes it easy for protecting them from degradation during baking or digestion in alimentary canal. The oleogels also help to reduce oil separation in products like chocolate, in which fat bloom due to oil can cause quality deterioration. The structuring agents in oleogels help to improve the nutritional quality of the final products.
4. Other methods to eliminate trans-fats in fried bakery products
Other effective methods to eliminate trans-fats in fried foods in bakery industry can be the modification of food surface using coatings like bread crumbs or batters, resulting in lesser oil intake for deep-fried goods like doughnuts or waffles. Vacuum frying and air frying techniques can be used to fry the foodstuffs at lower temperatures, thus causing lesser deterioration to oils. Studies have also proven that ultrasound or microwave treatment before cooking or baking can cause lesser oil absorption.
Modification of the frying medium also can help in lesser oil absorption. Utilisation of oleogel as shortening in batter-based products like waffles also can be effective. The fried foods can be half-fried and half baked to reduce oil uptake and to extend the shelf stability without affecting the sensory properties.
5. Conclusion
The increase in the global shift towards healthier diet choices has been a hurdle in the growth of the bakery industry. Also, the policies introduced in several nations and by WHO and FSSAI itself, has increased to need to makeshift the shortenings used and to adopt an alternative and cost-effective approach without disturbing the characteristic organoleptic properties of the bakery products. Edible oil structuring has been an efficient and successful solution for this problem. It forms solid fat using different gelators in edible oils, thus forming oleogels. The other approaches like air and vacuum frying and pre-conditioning of foods with ultrasound or microwave treatments can be effective line in fried bakery goods. However, further studies on the oil structuring process, structurants and shelf-stability of goods is going on effectively which can help in elimination of trans-fats from the bakery industry and food supply chains.
(Dr Natarajan is professor at Department of Food Engineering and Modupalli is a research scholar at Indian Institute of Food Processing Technology, Thanjavur. They can be contacted at venkat@iifpt.edu.in)
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