Wang Qiang, Xie Yuejie, Johnson David R, Li Yuanyuan, He Zhifei, Li Hongjun
College of Food Science Southwest University Beibei, Chongqing China.
College of Biological and Chemical Engineering Chongqing University of Education Chongqing China.
Food Sci Nutr. 2019 Jun 20;7(7):2361-2373. doi: 10.1002/fsn3.1083. eCollection 2019 Jul.
The current work aimed to evaluate the effect of ultrasonic treatment on the enzymatic transesterification of medium-long-medium (MLM) lipids using 2-monoacylglycerol, bearing distinct fatty acids at the -2 position with palmitic acid, octadecanoic acid, oleic acid, eicosapentaenoic acid, and docosahexaenoic acids as -2 acyl donors. The effects of ultrasonic treatment conditions, including substrate concentration, reaction temperature and time, and enzyme loading, on the insertion of fatty acids into the -2 acyl position of MLM lipids were investigated. The data showed that low-frequency ultrasonic treatment could remarkably improve the insertion rate of polyunsaturated fatty acid (PUFA) into the -2 position of MLM lipids, compared with the conventional treatment method. By increasing the ultrasonic frequency from 20 to 30 KHz, while maintaining power at 150 W, the rate of synthesis of monounsaturated fatty acid and PUFA increased from 23.7% and 26.8% to 26.6% and 32.4% ( < 0.05), respectively. Moreover, ultrasonic treatment reduced the optimum reaction temperature from 45 to 35°C. However, the activity of Lipozyme RM-IM treated with ultrasound considerably declined from 31.10% to 26.90% ( < 0.05) after its fourth cycle, which was lower than that without ultrasonic treatment. This work provokes new routes for the utilization of ultrasonic technology in the synthesis of MLM lipids using different fatty acids as -2 acyl donors.
当前的工作旨在评估超声处理对中长中链（MLM）脂质与2-单酰甘油进行酶促酯交换反应的影响，其中2-单酰甘油在-2位带有不同的脂肪酸，以棕榈酸、十八烷酸、油酸、二十碳五烯酸和二十二碳六烯酸作为-2酰基供体。研究了超声处理条件，包括底物浓度、反应温度和时间以及酶负载量，对脂肪酸插入MLM脂质-2酰基位置的影响。数据表明，与传统处理方法相比，低频超声处理可显著提高多不饱和脂肪酸（PUFA）插入MLM脂质-2位的比率。在保持功率为150 W的同时，将超声频率从20 kHz提高到30 kHz，单不饱和脂肪酸和PUFA的合成率分别从23.7%和26.8%提高到26.6%和32.4%（P<0.05）。此外，超声处理将最佳反应温度从45°C降低到35°C。然而，用超声处理的Lipozyme RM-IM在第四个循环后活性从31.10%大幅下降到26.90%（P<0.05），低于未进行超声处理的情况。这项工作为利用超声技术以不同脂肪酸作为-2酰基供体合成MLM脂质开辟了新途径。
