Synthesis of Ammonium-Based Ionic Liquids for the Extraction Process of a Natural Pigment (Betanin)

Pedro Morales-García,Irina V Lijanova,Evelyn Y Calvillo-Muñoz,Octavio Olivares-Xometl,Paulina Arellanes-Lozada,Natalya V Likhanova

doi:10.3390/molecules26185458

Abstract

The use of new synthesized ammonium-based ionic liquids was explored as an alternative to the current process implemented in the betanin extraction from red beet juice, resulting in high yields: 70% and 82%. Betanin is a vegetal pigment that has been applied to a large variety of products in the food industry, which is important, for it can work as a substitute for the red synthetic dyes used nowadays. Additionally, the use of the kosmotropic salt sodium acetate was explored in order to separate the complex formed by the ionic liquid and pigment of interest in a process that combined two techniques: ATPS (aqueous two-phase system) and SOES (salting-out extraction system). The results reveal that the studied techniques could work as a novel process for the extraction of betanin from red beet juice employing ionic liquids, which have not been tested for this purpose in other research.

Highlights

Ionic liquids (ILs) have started to play an important role as design-solvents in extraction processes of natural substances: phycobiliproteins from spirulina algae [1], the pigment curcumin [2], and anthocyanins [3]
Aqueous two-phase systems (ATPSs) [16] occur when combinations of hydrophilic solutes are incompatible in a specific aqueous solution above critical concentrations, and these systems have proved to be useful in different extraction processes of natural pigments [17,18,19]
For the design of the ILs used in the present work, it was necessary to consider the possible union sites in the betanin molecule (Figure 1), where the ILs could set up interactions, and to consider the physical properties of the pigment

Summary

Introduction

Ionic liquids (ILs) have started to play an important role as design-solvents in extraction processes of natural substances: phycobiliproteins from spirulina algae [1], the pigment curcumin [2], and anthocyanins [3]. The conditions of extraction processes of natural products are very important because they are susceptible to degradation due to factors such as high temperature (>70 ◦C), acid or alkaline pH, and air, betanins [7,8]. In this context, there are multiple reports on betanin extraction, employing different techniques: by low DC or pulsed electrical field [9,10,11], g-irradiation [12,13], diffusion apparatus [14], and ultrafiltration and osmotic distillation [15], but extraction by solvents is still the most used due to its simplicity and accessibility.

Methods

Results

Conclusion