ChainCountry code: us, country type: geoip, valid: 1 No.18088
>>18085
In a fatty acid, "bis-allylic site" refers to a carbon atom that is sandwiched between two double bonds (-CH=CH-CH₂-CH=CH-). This carbon has hydrogen atoms that are exceptionally vulnerable to attack since they are weakly bound. When one of these hydrogens get plucked off, the resulting lipid radical is highly stable due to resonance delocalization.
Most seed oils are high in linoleic acid (LA), a polyunsaturated fatty acid with a bis-allylic site. When such oil is held at high temps for long times (as in typical in restaurant deep frying), some LA molecules start losing their bis-allylic hydrogens, setting off a chain reaction that creates harmful oxidative byproducts such as 4-HNE and MDA. These byproducts end up in the oil and, consequently, in the fried food you eat.
H H H
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-C=C-C-C=C-
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H H H