Solvents are used widely in the food processing industry, from removing caffeine in coffee and tea to extracting essential oils for flavouring. Whilst synthetic, petroleum-derived solvents have historically dominated the market, recently, there has been a push from the food industry towards greener alternatives.
Currently, these include ionic liquids and deep eutectic solvents. Ionic liquids are non-flammable, have low vapour pressure, and are highly stable, but their production cost is prohibitively high for industrial users.
Deep eutectic solvents (DESs) appear to be more promising, as they have similar properties to ionic liquids, but can be made from naturally occurring metabolites, which means they are environmentally friendly, degradable, and cost-effective.
DESs are comprised of two or more solid components, which upon mixing, result in a new chemical entity with a lower melting point than the individual compounds. The word ‘eutectic’ comes from ancient Greece and means ‘easily melted’. The eutectic point is the specific point at which a mixture of two solids becomes fully molten.
Eutectics explained
“Eutectic technology works by mixing two natural solid compounds, such as sugars, alcohols, organic acids, amino acids, terpenes and many more. If you mix them under very specific conditions and in certain proportions, their melting point drops dramatically, generating physical interactions – mainly hydrogen bonds – that turn the two solids into a super stable liquid,” explained Tomas Silicaro, CEO and co-founder of Argentinean startup Bioeutectics.
Bioeutectics is on track to start producing eutectic solvents for the food, personal care, and agrotech industries by the end of this year from its facility in Oklahoma in the US.
“We have customers today who are testing our products in Belgium, France, Spain, Sweden, Switzerland, Japan, Argentina, Chile, and the USA,” Silicaro told this publication.
He said that Bioeutectics is the only company producing eutectic solvents on an industrial scale, but that it welcomes competition, given the scale of the challenge of eradicating organic solvents.
“To our knowledge, there are only a couple of other companies active in eutectics and they are operating at a niche level. The truth is that, the more companies in this space, the better as we need to change an industry that is very large and is not used to this type of solution.”
Mimicking metabolic processes in plants
Bioeutectics’ solution involves using biomimetics to replicate how plants produce their own solvents. To create biodegradable liquid solvents, produced by a purely physical process, the company uses sugar, alcohols, organic acids, amino acids, terpenes, ammonium salts, and amines.
“We don’t use any petroleum as a raw material, we don’t generate any dangerous waste, and we avoid the exposure of workers to dangerous chemicals,” Silicaro explained.
“The big difference with our products is that manufacturers will have a clean label both in terms of toxicity and chemistry,” he added.
For regulatory purposes, Bioeutectics’ solvents are a “functional mix of ingredients that are already used in the food industry”, so no regulatory approval is required; manufacturers simply need to list the raw materials on the label: citric acid and glucose, for example.
And with DESs, there is no need to evaporate the solvent after it has performed its function, Silicaro explained.
“You don’t need to remove the solvent from the food because it is not harmful; it is food grade and can stay in the ingredient after extraction,” he noted.
Bioeutectics already has 100 products that have been validated as replacements for solvents such as hexane, toluene, glycols, methanol, ethanol, and N-methylpyrrolidone, according to Silicaro.
“We are already testing our products with a lot of different customers. We have entered into joint development agreements and R&D agreements with some, and there are pilot projects underway,” said Silicaro.
Food applications: Colours, proteins, hydrocolloids, gums, and more
In the food industry, the extraction of colourants, fragrances, oils, essential oils, proteins, hydrocolloids, pectins, gums, alginates, and medicinal plants are some of the main applications for Bioeutectics’ solvents.
In particular, the company sees protein extraction as an area with major potential. “For protein extraction, we developed a method that avoids the use of sulphuric acid and sodium chloride,” said Silicaro.
Similarly, he explained that Bioeutectics has developed an alternative method for extracting pectin or alginates without any type of acid, using just one of its solvents.
“Not only did we replace the undesirable solvents that were being used, we even improved the concentration of the final extract whilst eliminating the post-extraction evaporation step.”
The company has also extracted beta-carotene from carrots, lycopene from tomatoes, and antioxidants from grapes that have been pressed for winemaking.
In some cases, as well as behaving as solvents, they behave as ingredients, performing additional functions in the product matrix.
“They can be antimicrobial agents, natural preservatives, natural stabilisers, antioxidants, and much more,” said Silicaro.
Bioeutectics has also conceived an AI platform that accelerates the development of new solvents, which it said reduces the discovery process from months to minutes. “It is giving us digital availability of thousands of natural raw materials that we can mix and match to make our products,” Silicaro added.
