Oxidative Stability of Enzymatically Processed Oils and Fats

Fats and oils with modified functional and nutritional properties are in high demand in the food industry. The physical characteristics of fats and oils-for instance, those related to their melting and crystallization profiles-are important for food technologists to consider because nutritionists and consumers display great interest in their nutritional properties, based on their composition. The fats and oils industry has extensively used chemical interesterification to alter the physical and/or nutritional properties of fats and oils. However, the random end products of chemical interesterification cannot meet the demand for lipids with specific structures and compositions. The enzymatic process, on the other hand, requires mild reaction temperature and pressure, which is vital for handling unsaturated Fatty Acids (FAs), and has some other advantages as well. Therefore, the enzymatic modification of fats and oils has been a popular topic for the past few decades. However, information on the oxidative stability of such products remains limited. This chapter reviews the newest developments regarding the oxidative stability of enzymatically processed fats and oils. Many researchers have noted that the reduced oxidative stability of fats and oils produced by enzyme-involving steps presents a disadvantage. Many explanations exist for the low oxidative stability of these products. One of them is that a change in lipid structure affects stability by increasing or decreasing the exposure of unsaturated FAs to oxygen as well as the oxygen solubility or diffusivity of sensitive FAs. Moreover, structural change may alter the state of metal ions in the system.