Fractionation of Short and Medium Chain Fatty Acid Ethyl Esters from a Blend of Oils via Ethanolysis and Short-Path Distillation

Summary

We were able to use short-path distillation to obtain useful fractions which can be used as starting materials in subsequent processes to produce structured lipids, nutraceuticals, functional foods, or other value-added products, such as antimicrobials and emulsifiers.

Situation

There are several studies as well as a number of reviews reporting uses of medium chain triacylglycerols (MCTs) and short (SCFA) and medium chain fatty acids (MCFA). MCTs are triacylglycerols with all three positions of the glycerol molecule esterified with C6:0 to C12:0 fatty acids, also known as medium chain fatty acids. SCFA, which range from 2 to 6 carbons long, have also been reported to possess bioactive properties. Consumption of these compounds was reported to provide a rapid source of energy that is readily digested and easily absorbed. MCTs are rapidly absorbed and transported to the mitochondria where they are utilized for fuel and may be less likely stored as body fat. MCFA do not require chylomicron formation and they are transported back to the liver directly by the portal system. MCT are used as a part of the fat blend for liquid diet formulas intended for patients with impaired digestion or diverse medical conditions requiring fluid restriction, such as AIDS, cystic fibrosis, postoperative cancer patients, multiple traumas, burn injury, respiratory distress, hepatic or renal disease. Classical processes such as distillation, urea complexation, low-temperature crystallization, or liquid-liquid extraction have been applied to fractionate numerous lipid samples from different sources. However, newer technologies, such as supercritical fluid extraction or short-path distillation are adequate for the production of food-grade ingredients and offer advantages against conventional methods, mainly due to the greener chemistry and mild conditions involved, enhanced versatility, selectivity, and efficiency. Short-path distillation is a process based on evaporation of molecules into a substantially gas-free space vacuum. The controlling factor is the rate at which the molecules escape from the heated surface of the distilling liquid and are received by the cooled condenser surface. Hence, short-path distillation offers an alternative method to fractionate lipid samples into a heavy fraction (residue) and a light fraction (distillate) on the basis of volatility. There are many examples of application related to lipids: fractionation of ethyl esters from marine sources, fractionation of milk fat, or purification of structured lipids.

Response

In the present study, dairy fat and coconut oil were blended (1:1, vol/vol) to obtain a suitable raw material composed mainly of triacylglycerols rich in butyric, caproic, caprylic, capric and lauric acid residues. In this study, the composition of the original blend of oils was transformed by converting the triacyglycerols into FAEE. In the second step, we studied the fractionation of the FAEE produced using short-path distillation. The fractionation was based on the different volatility of FAEE and mainly on their different chain lengths. Composition and yield of distillates and residues were determined in order to describe the process and to determine the most important conditions.

Impact

The main objective of the present work was to obtain fractions enriched in short (SCFAEE) and medium chain (MCFAEE) fatty acid ethyl esters (FAEE). For this purpose, coconut oil and dairy fat were blended and a transesterification of this blend was performed in order to transform the triacylglycerols into their corresponding FAEE. A detailed study of fractionation conditions for FAEE was carried out using short-path distillation. Different conditions were explored such as feed rates and temperatures; operating conditions, such as successive steps or a single step. The composition and yield of SCFAEE and MCFAEE were determined at different distillation conditions. Optimal fractionation of desired compounds was achieved. High purity of SCFAEE and MCFAEE (94 wt.%) was attained in with a yield of ~50%. An increased yield of SCFAEE and MCFAEE was achieved (85%) with a purity of 83 wt.%. A broad range of high value fractions were obtained depending on conditions selected. The fractions we obtained can be used as starting materials for the production of functional lipids.

State Issue

Food, Nutrition and Health

Details

• Year: 2010
• Geographic Scope: University
• County: Clarke
• Program Areas:
  • Agriculture & Natural Resources