Deacidification of Palm Oil Using Betaine Monohydrate-Carboxylic Acid Deep Eutectic Solvents: Combined Extraction and Simple Solvent Recovery

Kamarza Mulia,Ida Zahrina,Elsa Anisa Krisanti,Mohammad Nasikin

doi:10.3390/pr8050543

Abstract

Steam stripping is commonly used to remove free fatty acids from crude palm oil. An alternative deacidification method, solvent extraction performed at a much lower temperature, would preserve the natural antioxidants in the refined palm oil. In this work, palmitic acid was extracted using betaine monohydrate-propionic acid and betaine monohydrate-acetic acid deep eutectic solvents (DESs). The effect of temperature (40 °C to 80 °C), mass ratio of palm oil to solvent (2:1 to 1:2), and palmitic acid content in the palm oil feed (2% to 8% mass) on the distribution coefficient values of palmitic acid (0.44–0.93) was investigated. For the first time, a facile recovery of DESs could be accomplished by a cooling process where up to 98% of the palmitic acid separates as solid. A solvent extraction process for palm oil deacidification, employing a DES with a distribution coefficient value much higher than unity, will provide advantages over the steam stripping process.

Highlights

In the palm oil industry, steam stripping is a common deacidification method used to remove undesirable materials such as free fatty acids, mainly palmitic acid (41%–47%) and oleic acid (36%–41%) [1]
The distribution coefficient values obtained using the betaine monohydrate-propionic acid and betaine monohydrate-acetic acid deep eutectic solvents (DESs) as a function of the mole fraction of acid are shown in Figures betaine monohydrate-acetic acid
This study shows the advantages of using DESs to separate palmitic acid from palm This study shows the advantages of using DESs to separate palmitic acid from palm oil, as no oil, as no byproducts are formed, and the antioxidants practically remained in the palm oil

Summary

Introduction

In the palm oil industry, steam stripping is a common deacidification method used to remove undesirable materials such as free fatty acids, mainly palmitic acid (41%–47%) and oleic acid (36%–41%) [1]. The presence of free fatty acids in palm oil indicates that degradation has occurred. As free fatty acids are susceptible to autoxidation, affecting the organoleptic qualities of the oil, palm oil is refined to obtain a stable product for consumption [2]. In a steam deacidification optimization study, the final oil acidity was found to be dependent on temperature, percent of stripping steam, and composition of the model palm oil [6]. Other deacidification methods have been investigated, including esterification reaction of the free fatty acid with methanol catalyzed by an acid ion exchange resin [7], and with glycerol catalyzed by a lipase enzyme [8]

Methods

Results

Conclusion