The Trans-Fat Dilemma : Health VS Functionalities
by Kalyana Sundram & Yusof Basiron

Malaysian Palm Oil Council (MPOC), 2nd Floor Wisma Sawit, Lot 6, SS6 Jalan Perbandaran, 47301 Kelana Jaya, Selangor, Malaysia
E-mail: kalyana@mpoc.org.my, yusof@mpoc.org.my

Natural fats as the choice for trans-free fat formulations

Deep-frying is an important food preparation / processing method practiced universally.
For deep-frying purposes the oil or fat should have low PUFA especially, linolenic acid which tends to oxidize very rapidly. Commercial frying operations tend to use solid fats rather than liquid oils, primarily to minimize oxidation of the oils and to extend the shelf life of the fried products. Interestingly, very few of the unsaturated oils can be used for industrial frying. The common approach has been to partially hydrogenate liquid oils to eliminate their linoleic acid content and also reduce linoleic acid. Current preference is to choose newer varieties of high oleic oils and palm olein, which have been shown to be stable during industrial (continuous) frying operations. Another common alternative is to blend unsaturated vegetable oils with palm olein to reduce the overall linoleic acid content and confer stability to such blends [11]

Shortenings, including bakery fats are used extensively in the food industry. Originally intended as a replacement for lard, partially hydrogenated fats became a mainstay in most shortening formulations. An important function of a shortening is its ability to incorporate and then hold air when beaten in a cake batter or creamed with sugar. The trapping of air facilitates the formation of a porous structure and increases volume of the cream and the baked product. Shortenings also contribute to lubrication and give the dough the required final consistency. Such properties cannot be imparted by native liquid oils, which lack the appropriate solids content [12]. Palm oil is an exception since it is natural semi-solid fat. The quantity of palm oil incorporated into shortening generally varies from 30 – 40%. Currently many manufacturers are able to incorporate up to 80% of palm oil and its fractions in their shortening formulations. This is made possible because palm oil has 22-25% solids at 200C and it stabilizes the shortening and assists in good baking performance. A variety of trans-free cake shortenings are possible with palm-based products and these can be specially designed for very specific applications such as layer and pound cakes, sweet dough, breads and cream fillers. Palm based shortening are also excellent as pastry and bread fats [11].

Margarine is defined as liquid or plastic emulsion containing not less than 80% fat, not more than 16% water and fortified with vitamin A. There are several types of margarine, each formulated to fulfil a specific requirement. Good physical properties necessary for quality margarine include emulsion stability without oil separation, no brittleness, good spread ability and a clean, smooth melt in the mouth. Margarine must be firm but spread able and these properties are related to the proportion of solid and liquid fat in the product at a given temperature. These requirements make it impossible for liquid oils in their native state to be incorporated in these formulations, unless a portion is also hydrogenated, giving rise to TFA.  Margarine made significant progress at the expense of butter as the healthy alternate solid fat and a variety of PUFA margarines containing TFA were the norm until a decade ago. With increasing awareness about the detrimental effects of TFA [1-6], these TFA containing margarines are being phased out in favour of natural fat based formulations. In such products palm oil has become a favoured ingredient. Alternately, by suitably modifying natural semi-solid and solid fats through fractionation, interesterification or blending, it is possible to produce a variety of margarines that are TFA-free.