Use of hydrogenated fats has been an industry standard for a number of years because of the technological necessity to impart the desired texture and other quality features typical of many bakery products. Discovery of trans fats present in such man made food ingredients and their role in causing health disorders, similar to that caused by high levels of saturated fats in the diet, led more stringent regulation of their use in foods. Though their use is not banned, the compulsory label declaration provision in the food laws, made the processors voluntarily cut down their use. Of course like any other issue, the subject matter of trans fats in foods also is a controversial area though there is unanimity regarding the health risks posed by high levels of these optical isomers of desirable unsaturated fatty acids. Some of the products are reported to contain trans fats as high as 30% which definitely poses serious health risks when consumed regularly. It is this factor which is propelling scientists to evolve trans fat free alternatives to hydrogenated fats
"Shortening is generally a semisolid fat for use in food preparations, especially of baked goods; so called because it promotes a 'short' or crumbly texture. Walker his and colleagues explained that shortening is a major ingredient in high-ratio layer cakes; cakes in which there is as much or more sugar than flour in the formula. Shortening performs three basic functions in such cake products: it traps air during the creaming process, coats protein and starch particles, and emulsifies large amounts of liquid. Solid 'plastic' shortenings are the most commonly used type of shortening in the baking industry. However they often contain a high proportion of hydrogenated fats, including trans-fats. Research has highlighted that trans-fats in the diet may increase the risk of coronary heart disease, by raising the levels of LDL cholesterol and lowering the levels of HDL cholesterol. Walker and his co-workers explained that 'liquid' cake shortenings function much like solid shortenings in baking systems, but they offer the user certain advantages, including having a healthier fat profile".
"The authors explained that as industry moves away from the use of trans-fats in its formulations, it is important to look at the properties of replacement ingredients, in order to achieve the most effective yet healthy profile. "Many companies began to use the relatively inexpensive palm oil instead of hydrogenated soybean oil to make zero-trans fat shortenings. Ironically, the high levels of saturated fatty acids in palm oil result in the same cardiovascular problems as do trans-fats," said the authors, led by Dr Chuck Walker from the department of grain science & industry at Kansas State University, USA. "For baking companies, a liquid oil plus an emulsifier combination blend would be easy to handle and they could combine different emulsifiers as their requirements change," they added. However, the authors conceded that investment in equipment, and a skilled staff to prepare such shortenings would be required".
Since animal fats like that present in milk do contain 1-4% trans fats about which nothing much can be done, there is a perception that the diet normally consumed should have less than 1%. As the bakery industry needs technically suitable fat ingredients that will ensure high eating quality in their products, innovative attempts to mimic the action of plastic fats are being made and use of emulsifiers with liquid oils seems to be giving satisfactory results as indicated by the above finding. Probably more research efforts may be required to develop this theme further so that use of high trans fat containing ingredients are eventually phased out.