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
Fat Modification Processes and Their Nutritional Consequences
Hydrogenated fats are on their way out as a result of these developments and health concerns. The question that is paramount currently is how best to reformulate margarine, vanaspati, bakery, frying, and other solid fats such that these products are trans-free. Reformulated solid fats should not contain increased contents of SFA. A primary consideration in the food industry today is to count the sum of TFA and SFA as cholesterol elevating. A reformulated product at best must reflect significantly reduced amounts of this arithmetic sum if the stated goal of designing healthier solid fats is achievable. The choice now appears to be narrowed between natural semi-solid fats such as palm oil, cottonseed oil and / or TFA-free interesterified fats.
Sterospecificity of most natural oils and fats favour placement of the polyunsaturates (PUFA) and monounsaturates (MUFA) in the sn-2 position whilst SFA are distributed in the sn1, 3 positions [8]. An obvious attempt to use available liquid oils and hydrogenation capacities would be to fully hydrogenate the liquid oils into a hard stock. This would mean conversion of all the 18-carbon fatty acids (18:1, 18:2 and 18:3) in liquid oils to a stearic acid (18:0) block. Another common fat modification tool, interesterification, would then gain greater acceptance since it would allow fully hydrogenated vegetable oils to be randomized with the native vegetable oils to provide the required hard stock for solid fat formulations. This approach has great merit since currently stearic acid is considered a neutral fatty acid with respect to CHD risk. However this initiative may not be so straightforward since new concerns regarding the nutritional efficacy of strearic-rich interesterified hard stock could likely arise in the near future. Enzymatic interesterification of fats using enzyme technology allows placement of mostly SFA in the sn1, 3 positions of the triacylglycerol (TAG) molecule and unsaturated fatty acids in the sn2 position.
Interesterification, the process increasingly being viewed as a viable alternate to hydrogenation (to produce higher melting fats) has the capacity to invert the fatty acid distribution and alter nutritional effects. Although such rearrangement of fatty acids within TAG has been postulated to result in beneficial effects for lipoprotein metabolism, the current evidence is rather divided [9]. In palm oil, redistributing C16:0 in the sn-2 position has been reported to increase TC and LDL-C while other studies suggest no significant effects on these lipoproteins. In an atherogenic rabbit model, interesterified palm oil has been shown to be more atherogenic than its natural counterpart [10]. A recent human study that compared a chemically interesterified-stearic-rich fat (IE), trans-rich hydrogenated fat and natural semi-solid fat showed that the physiologically important lipoprotein ratios (TC/HDL-C and LDL/HDL-C) and plasma glucose response in healthy subjects was adversely impacted by the IE and trans-rich fats compared to the natural semi solid fat (unpublished data, Sundram et al. 2005). These findings are suggestive in that the possible alternate to hydrogenated fats in the form of fully hydrogenated-interesterified fats are equally worrisome for lipoprotein metabolism, CHD and diabetic risks. These developments if proven correct, could force the food industry to re-think its current strategies for solid fat formulations.
| Prev Page (1/4) | Page 2 | Next Page (Page 3/4) |
|
||||||||||||||||||||||||||||||||
Disclaimer : Malaysian Palm Oil Council (MPOC) shall not be liable for any loss or damage caused by the usage of any information obtained from this site. Companies referred to in this website shall not be construed as agents nor as companies recommended by MPOC.