Assessment of dialklyl ketones formation during interesterification of edible oils and fats.

Abstract

The interesterification process has emerged as a replacer of partial hydrogenation without its negative health aspects. Both chemical (CIE) and enzymatic (EIE) interesterification techniques are employed to create fats with improved character- istics for trans-free applications. However, a process-induced byproduct, known as dialkyl ketones (DAKs), was found to be associated with CIE technology, whereas EIE did not exhibit this phenomenon1–3. No current information exists on the ef- fects of DAKs intake on human health. This study aimed to investigate DAKs formation during IE, determining favorable conditions and strategies to minimize or prevent their occurrence. Five edible oils and fats were selected : Elaeis Guineensis palm stearin (POSt), high oleic palm stearin (HOPSt), palm kernel stearin (PKSt), high oleic sunflower oil (HOSO), and high oleic palm oil (HOPO). Blends were then composed : PKSt:HOPO, POSt:HOPO, HOPSt:HOPO, and POSt:HOSO (30:70 ; 50:50 ; 70:30 w:w%). These blends were subjected to both CIE (using sodium methoxide as catalyst) and EIE (using TLIM lipase) and analyses covering physical properties and DAKs content determination based on an optimized MAS-SPE method were conducted. This study supports that DAKs are completely absent from EIE process regardless of the matrix. On the contrary, DAKs are correlated with CIE but needs a sufficient triglycerides (TAG) rearrangement to be produced. Regardless the fat matrix, un- saturated fatty acids seem to be more likely to form DAKs. However, there is no linear relation between DAKs amount and the proportion of unsaturated fat in the matrix. Oil quality and/or catalyst concentration have also an influence on DAKs formation. This study finally provides interesting information relative to DAKs formation and supports EIE as a promising technology for the future.