Interesterified fat
Interesterified fats are oils (such as soybean oil) that have been chemically modified. This is done in order to make them more solid, less liable to go rancid and more stable for applications such as deep frying. The interesterification process is used as an alternative to partial hydrogenation, which results in trans fats. However, research indicates that interesterified fats may pose health risks, some greater in magnitude than trans fats.
Chemistry
In a polyunsaturated fat, one or more polyunsaturated fatty acids (PUFA) are esterified to a glycerol backbone.
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Interesterification is used to replace the PUFA with a saturated fatty acid, typically stearic acid. The process can be applied to natural oils or fats, or hydrogenated or fractionated oils. It can be induced by chemicals or enzymatic catalysts. The interesterified fats can be separated through controlled crystalization.[1] Interesterification does not introduce trans fatty acids. However, the resulting fat can be subtly different than natural oils. In polyunsaturated fats, the PUFA is commonly found at the middle position (sn2) on the glycerol. Stearic acid is not usually found at sn2 in vegetable oils used in the human diet.[2]
Health effects
Research has raised concern about interesterified fats. Stearic acid is used because, unlike other saturated fats, it does not raise LDL. However, reasearch has suggested that replacing a polyunsaturated fatty-acid molecule in vegetable oil with stearic acid might pose problems if that stearic acid is placed in the middle fatty-acid position on a fat molecule, since it is not as easily metabolized.[2] Other, early research shows that interesterified fats may raise blood sugar levels and lower HDL even more than trans fats.[3] [4]
References
- ^ "Kellens, Marc" (2000). "Interesterification Process Conditions" (PDF). Retrieved 2007-01-29.
- ^ a b Shelley Wood (2007-01-19). "Risks in New Fat May Be Similar to Trans Fat". Retrieved 2007-01-19.
{{cite web}}: Cite has empty unknown parameter:|1=(help)CS1 maint: year (link) - ^ Sundram K, Karupaiah T, Hayes K. (2007). "Stearic acid-rich interesterified fat and trans-rich fat raise the LDL/HDL ratio and plasma glucose relative to palm olein in humans" (PDF). Nutr Metab. doi:10.1186/1743-7075-4-3. Retrieved 2007-01-19.
{{cite journal}}: CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link) - ^ "New Fat, Same Old Problem With An Added Twist? Replacement For Trans Fat Raises Blood Sugar In Humans". Science Daily. January 18, 2007. Retrieved 2007-02-05.