Enhancement of Lipid Extraction from Soya Bean by Addition of Dimethyl Ether as Entrainer into Supercritical Carbon Dioxide

Abstract

Soya beans contain a variety of lipids, and it is important to selectively separate neutral lipids from other lipids. Supercritical carbon dioxide extraction has been used as an alternative to the selective separation of neutral lipids from soya beans, usually using non-polar hexane. However, supercritical carbon dioxide extraction has a high operating pressure of over 40 MPa. On the other hand, liquefied dimethyl ether extraction, which has attracted attention in recent years, requires an operating pressure of only 0.5 MPa, but there is concern about the possibility of an explosion during operation because it is a flammable liquefied gas. Therefore, this study aims to reduce the operating pressure by using a non-flammable solvent, supercritical carbon dioxide extraction mixed with liquefied dimethyl ether as an entrainer. The extraction rate and the amount of neutral lipids extracted increased with increasing amounts of added liquefied dimethyl ether. In the mixed solvent, the amount of neutral lipids extracted was higher at an operating pressure of 20 MPa than in pure supercritical carbon dioxide extraction at 40 MPa. The mixing of liquefied dimethyl ether with supercritical carbon dioxide allowed an improvement in the extraction of neutral lipids while remaining non-flammable.

Extraction and Separation of Natural Products from Microalgae and Other Natural Sources Using Liquefied Dimethyl Ether, a Green Solvent: A Review

“…DME has similar physical properties to LPG and has been developed as a synthetic fuel. In China, it is used commercially as a substitute for LPG in city gas, often blended with 20% propane for consumer use [137]. It is also used as a fuel in automotive and industrial applications.…”

“…It is also used as a fuel in automotive and industrial applications. However, pure DME has an explosive range of 3.427 vol% in air, which is a significant safety concern when used as an extraction solvent [137]. To address this issue, the blending of DME with CO 2 has been investigated.…”

“…To address this issue, the blending of DME with CO 2 has been investigated. When the mole fraction of CO 2 exceeds 0.882, the mixture falls out of the explosive range and becomes non-flammable [137]. In addition to flammability concerns, DME offers unique extraction capabilities.…”

“…In addition to flammability concerns, DME offers unique extraction capabilities. DME, although weakly polar, has the ability to extract both polar and nonpolar substances, unlike supercritical carbon dioxide and hexane that are non-polar and selectively extract non-polar substances [137].…”

Surfactant-Free Decellularization of Porcine Auricular Cartilage Using Liquefied Dimethyl Ether and DNase

“…DME is a solvent frequently used for the extraction of organic matter; for example, extraction from rice bran [24], river sediment [25], sugarcane leaves [26], hop [27,28], microalgae [29], livestock waste [30], soy beans [31], milk [32], and plants [33] has been demonstrated. The ability to handle high-moisture objects stems from the weak hydrogen bonds in DME [34], which allow liquefied DME to partially mix with water [35][36][37].…”