Effect of enzymatic interesterification on physiochemical and thermal properties of fat used in cookies

• The interesterified fat was used in the recipe of cookies.
• The kinetic parameters of the oxidation process were calculated.
• The structure of triacylglycerols in fat in cookies is similar to the human milkfat.
• Interesterification of fats reduces their oxidative stabilities.
• Interesterified fat is suitable for bakery applications.

Lard (L), rapeseed oil (RSO) and fish oil (ROPUFA) (7:2:1 wt ratio) were enzymatically interesterified at 50 °C for 4 h in the presence of Lipozyme RM IM as a catalyst. Interesterified fat was used to bake cookies. Fatty acids composition and their distribution between triacyglycerols, acid value, polar fraction content, induction time were determined in noninteresterified and interesterified fat, and in fat extracted from cookies. The kinetic parameters of the oxidation process (activation energy, pre-exponential factor, and reaction rate constants) were calculated. Melting profiles were also monitored by DSC in order to evaluate physical properties of noninteresterified and interesterified fats. Interesterification reduced the induction time, and activation energy of oxidation process, and increased acid value and polar fraction content. Fat extracted from cookies oxidized slower than the interesterified fat used in cookies formulations. The melting range of interesterified fat is extremely wide, which generally is suitable for bakery applications.