Fat interesterification

In the food industry and biochemistry, interesterification (IE) is a process that rearranges the fatty acids of a fat product, typically a mixture of triglycerides.

The process implies breaking and reforming the ester bonds C–O–C that connect the fatty acid chains to the glycerol hubs of the fat molecules.

In contrast to hydrogenation, interesterification itself generally retains the original distribution of fatty acids in the product and hence is expected to preserve its nutritional and health attributes.

The reaction is carried out at high temperatures and creates three by-products — sodium soaps, fatty methyl esters, and monoglycerides, in addition to the interesterified fats.

The earliest record of enzymatic interesterification was in 1844, when Théophile-Jules Pelouze published a study on the synthesis of a triglyceride through the esterification of glycerol by butyric acid.

[18] This process became a viable option for the food industry, as it improved the spreadability and baking properties of the common shortening lard.

Their work proved that the use of a specific enzyme predictably rearranged the fatty acids on the glycerol backbone of a triglyceride at positions 1 and 3.

It was only in the 2000s that general concerns about the health effects of trans fats drove the industry to adopt interesterification as a replacement for partial hydrogenation, which had been the oil hardening method of choice due to its lower cost.