JNU-UPM International Joint Laboratory on Plant Oil Processing and Safety, Department of Food Science and Engineering, Jinan University, Guangzhou, Guangdong 510632, China.
JNU-UPM International Joint Laboratory on Plant Oil Processing and Safety, Department of Food Science and Engineering, Jinan University, Guangzhou, Guangdong 510632, China; Department of Food Science and Technology, The University of Georgia, Athens, GA 30602, USA; National R&D Center for Freshwater Fish Processing, Jiangxi Normal University, Nanchang, Jiangxi 330022, China.
Food Chem. 2021 Jun 15;347:129070. doi: 10.1016/j.foodchem.2021.129070. Epub 2021 Jan 13.
Interesterification is widely employed as an effective technique to modify oils and fats. This study utilizes palm-based oil (palm olein: palm kernel oil: palm stearin, 5:3:2, w/w/w) as the raw material for the interesterification process performed in a pilot-scale packed bed reactor. Enzymatic interesterification (EIE) was catalyzed by Lipozyme TL IM (813.0 g) at 60℃ with reaction flow rate of 100 mL/min. Chemical interesterification (CIE) was catalyzed using sodium methoxide (0.3 wt%) as catalyst at 105 °C for 30 min. The results showed that the EIE fats had lower solid fat content tendency compared to that of CIE fats. The crystallization onset temperature was higher in EIE fats (23.09℃) compared to that of CIE (19.08℃). The results were consistent with the crystallization kinetics whereby the Avrami K constants of EIE fats were higher than that of CIE fats at various temperatures, indicating rapid crystallization and instant nucleation. Linear growth mechanism was dominant and the crystals formed were smaller in size as observed using polarized light microscope. The interesterified fats exhibited the presence of β and β'-crystals. While most of the tocopherol content was retained after EIE (386.18 ug/g), the molecular distillation process reduced the tocopherol concentration (110.01 ug/g) which consequently affected the oxidative stability. The findings in this work contribute to the fundamental understanding on the differences between CIE and EIE fats and provides data to support the preparation of modified fats via EIE that shows great potential as a controllable technique for industrialization.
酯交换广泛应用于油脂的改性。本研究以棕榈油（棕榈仁油：棕榈硬脂，5：3：2，w/w/w）为原料，在中试规模填充床反应器中进行酯交换反应。采用脂肪酶 TL IM（813.0 g）在 60℃下进行酶促酯交换（EIE），反应流速为 100 mL/min。采用甲醇钠（0.3 wt%）作为催化剂在 105℃下进行化学酯交换（CIE）30 min。结果表明，EIE 脂肪的固体脂肪含量趋势低于 CIE 脂肪。EIE 脂肪的结晶起始温度（23.09℃）高于 CIE 脂肪（19.08℃）。结果与结晶动力学一致，即在不同温度下，EIE 脂肪的 Avrami K 常数均高于 CIE 脂肪，表明结晶迅速，成核瞬间完成。线性生长机制占主导地位，用偏光显微镜观察到形成的晶体较小。酯交换脂肪表现出β和β'-晶体的存在。虽然 EIE 后大部分生育酚含量得以保留（386.18 ug/g），但分子蒸馏过程降低了生育酚浓度（110.01 ug/g），从而影响了氧化稳定性。本工作的研究结果有助于深入了解 CIE 和 EIE 脂肪之间的差异，并为通过 EIE 制备改性脂肪提供数据支持，EIE 作为一种可控的工业化技术具有很大的潜力。
