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designing foods with trans-fat alternatives must be a 'multidisciplinary' approach, say danisco scientists in a review that looks towards a trans-fat free future. paul wassell and niall young from danisco's multiple food application group review the state of play for current trans fat alternatives in the current issue of the international journal of food science and technology , as well as looking to the future with the potential of exotic oils to fill the void left by removing trans fats from food. though trace amounts of trans fats are found naturally, in dairy and meats, the vast majority are formed during the partial hydrogenation of vegetable oil that converts the oil into semi-solids for a variety of food applications. trans-fatty acids are attractive for the food industry due to their extended shelf life and flavour stability, and have displaced natural solid fats and liquid oils in many areas of food processing. numerous studies in the literature show that trans fatty acids raise serum levels of ldl-cholesterol, reduce levels of hdl-cholesterol, can promote inflammation, can cause endothelial dysfunction, and influence other risk factors for cardiovascular diseases (cvd). "successful replacements of trans fatty acids is not easily achieved by simply removing the trans isomer, because of a host of beneficial functional characteristics that are readily attributable to trans fatty acids," wrote wassell and young, pointing out that the presence of the trans isomer influences melting behaviour, oxidative stability and textural properties. lead author paul wassell told foodnavigator.com that the pace of this change is getting increasingly faster. "today's consumers, and the powerful supermarkets, are forcing these changes with increasing pace. because of this aspect, it requires new innovative steps to utilize ready available materials, and where possible these should come from "natural" sources," he said. according to wassell and young, there exists significant potential for allanblackia seed oil, extracted from plants that grow in many areas of africa. a novel food application was submitted to the ec last summer for using the oil in edible spreads and creams and to replace palm oil and palm kernel oil. "allanblackia is unique in the fact that is contains high levels of stearic-oleic-stearic (sos) and stearic-oleic-oleic (soo)," they said. "allanbackia contains approximately 45-58 per cent stearic and 41-51 per cent oleic acid, along with other fatty acids commonly found in the diet and is solid at room temperature," they added. however, the novel food application is still under review, and the advisory committee on novel foods and processes (acnfp) expressed concern that one of the sources of the novel food ingredient, allanblackia stuhlmanii , is considered a threatened species. questions were also raised about uniformity of the oil and whether the oil quoted in the novel food application would be representative of the full diversity of allanblackia species. wassell told this website that currently allanblackia is not grown in any great quantity. "it will likely not be cost effective yet, and will also require long term management if it were to become a future commodity oil in 10 to 20years," he said. the denmark-based scientists also consider the potential of stanol and sterol fatty acid esters, which are reported to form crystal networks that are similar to conventional hardstock triglycerides. a final consideration was given for the potential role of enzymes to offer innovative oils with similar properties to trans fats without the unnecessary health concerns. "[we] speculate that the current increase in the use of biotechnology will lead to the increased use of enzymatic technology that will come to the fore in the future," said wassell and young. "this is highly likely to open up new and exciting possibilities in the region of making and modifying new lipid structuring materials, inherently free from trans fatty acids." another danish company, novozymes, has already achieved recognition for its enzymatic interesterification process, which uses enzymes to develop healthier fats and oils for use in margarine, baking and confectionery applications. novozymes says that chemical interesterification, another method of adjusting the melting point of fats, has unwanted side effects. it has a negative impact on the environment and leads to discolouring of the fat, which means that further processing is required. using enzyme technology on the other hand means that trans fats are avoided, the environment is spared, and a natural product is obtained with natural flavours and better retention of other healthy substances from the oils. denmark has been leading the way in trans-fat removal from food. the scandinavian country introduced legislation in 2004 that required locally and imported foods to contain less than two per cent industrially made tfas, a move that effectively abolished the use of partially hydrogenated vegetable oils in the country. other countries are now following suit with new york's city board of health banning trans-fats from restaurants in december 2006. on 31 january, the british retail consortium announced that its members, including all the major food retailers, would voluntarily remove industrially added tfa from all new stocks of own brand products by the end of this year.