因天然油脂的组成成分和三酸甘油酯结构上的差异进而影响油脂的理化特性，较难满足消费者营养的需求且在应用上受到限制。因此为符合民众的健康需求，食品产业的发展逐渐导向将油脂特性修改，称为油脂改性 (oils and fats modification technology)，其中改性技术又可分为分提技术 (fractionation technology)、氢化技术(Hydrogenation technology)及交酯化技术 (Interesterification technology)，其中最常用的技术即为分提技术。 

Fractionation is a separation process in which a certain quantity of a mixture (gas, solid, liquid, enzymes, suspension, or isotope) is divided during a phase transition, into a number of smaller quantities (fractions) in which the composition varies according to a gradient. Fractions are collected based on differences in a specific property of the individual components. A common trait in fractionations is the need to find an optimum between the amount of fractions collected and the desired purity in each fraction. Fractionation makes it possible to isolate more than two components in a mixture in a single run. This property sets it apart from other separation techniques.