Molecular distillation and characterization of diacylglycerol‐enriched palm olein

Abstract

Lipase-catalyzed glycerolysis of palm olein was used to produce a mixture of acylglycerols with $34-wt% of DAG. The reaction conditions were 5-wt% of Lipozyme TLIM at 55°C and 8 h of reaction time. For commercial purposes, it is required to purify the product up to 80-wt% DAG and with free fatty acids (FFA) content below 0.1-wt%. A single-step distillation process was not sufficient to meet this product requirement. Two distinct 2-step short path distillation approaches were then studied. First scheme involved the removal of TAG by initial distillation step at 250°C, followed by separation of the MAG and FFA from distillate obtained at 180°C during second distillation step at vacuum pressure of 0.1 Pa. Second scheme involved the removal of MAG and FFA in first step at 180°C prior to purification of DAG from residue at 250°C during second distillation step at vacuum achieved up to 0.1 Pa. The results suggested that the first scheme of 2-step distillation operation was able to achieve 89.9-wt% of DAG purity without exceeding the limit of 0.1-wt% of FFA. A final yield of 21.5-wt% and DAG recovery of 47.8% were obtained using the first scheme. A detailed DAG profile was identified and product characterizations such as fatty acid composition, slip melting point, and solid fat content profile were also investigated. It was observed that purified-DAG product showed lower iodine value and higher slip melting point than raw material palm olein. The final product had 1134 AE 10 ppm tocols content.Practical applications: This paper has two main practical applications: (i) Enables production of highly purified DAG-based palm olein via appropriate processing method and processing conditions. (ii) Provide knowledge and understanding of the physicochemical properties of DAG-enriched palm olein fraction, which is a crucial aspect in food applications.

Production and concentration of monoacylglycerols rich in omega-3 polyunsaturated fatty acids by enzymatic glycerolysis and molecular distillation

“…Previous studies about SPD show that the operating parameters having greater effect on the separation efficiency are evaporator temperature, feed flow rate, and vacuum pressure (P. B. L. Fregolente, Pinto, Wolf-Maciel, & Filho, 2010;Yeoh, Phuah, Tang, Siew, Abdullah, & Choong, 2014). The feed temperature, the condenser temperature, and rotational speed have little influence on the separation (Zhang, Liu, & Liu, 2013;Zhu, Li, Wang, Yang, & Ma, 2011), and in this work, these parameters were fixed at 45 °C, 50 °C and 375 rpm, respectively.…”

“…SPD was performed to obtain a highly pure MAG fraction after the glycerolysis reaction. The order of removal in the distillate stream would follow the same order as vapor pressure of different acylglycerols: Glycerol < FFA < MAG < DAG < TAG (Yeoh, Phuah, Tang, Siew, Abdullah, & Choong, 2014).…”

“…while low flow rate fosters efficient separation, yet increases the processing time (Yeoh, Phuah, Tang, Siew, Abdullah, & Choong, 2014). In several studies, the feeding rate was around 1.5 mL/min for a UIC KDL1 system (Zha, Chen, Wang, Wang, Chen, & Zheng, 2014;Zhang, Liu, & Liu, 2013) and for MD-S80 distiller (Zhu, Li, Wang, Yang, & Ma, 2011).…”

“…Most of the studies about the separation of MAG from DAG and TAG mixtures by SPD are focused on purification of saturated and monounsaturated compounds such as monoolein by glycerolysis from coconut oil (Zha, Chen, Wang, Wang, Chen, & Zheng, 2014), or high oleic sunflower oil (Zhu, Li, Wang, Yang, & Ma, 2011). Concentration of MAG and DAG by SPD from glycerolysis of palm olein (Yeoh, Phuah, Tang, Siew, Abdullah, & Choong, 2014), soybean oil (P. B.…”

Synthesis, physicochemical properties, and health aspects of structured lipids: A review

“…In addition to physical properties, the oxidative stability of SLs also needs to be assessed as a function of chemical structure and processing conditions (Shahidi & Zhong, 2010). Compared to unmodified fats and oils, SLs are produced by applying extra processing and purification steps with altered fatty acid profiles and even acylglycerol composition (Osborn & Akoh, 2002;Sproston & Akoh, 2016b;Yeoh et al, 2014). Furthermore, when they are applied in the form of emulsions (Diao, Guan, Zhao, Chen, & Kong, 2016;Kabri et al, 2013;Zou & Akoh, 2015b), SLs may exhibit a more complicated behavior regarding oxidative stability, which need to be fully understood and controlled for extended shelf-life and acceptable quality.…”