Solvent-Free Extraction Of Botanical Ingredients

Tuesday, September 12th, 2017

In the search for all-natural ingredients, botanical extracts are attracting more attention. Extracting these through a novel, pressurised-water botanical extraction process might soon make current industrial solvent extraction processes obsolete. By Ben Lightburn, CEO, Mazza Innovation

The industry has been seeing a long-term secular international trend of consumers demanding clean-label and more natural foods and beverages for their families. But we are also seeing consumers begin to ask questions about the ingredients in the foods and supplements they consume. Just how natural are these products that are touted to be ‘naturally sourced’ or ‘organic’? How are their ingredients extracted?

For food and beverage manufacturers, incorporating botanical extracts as ingredients for their products presents a significant challenge. This is because the process by which many of these natural botanical ingredients are extracted and purified to make food products and supplements is anything but natural.

What is not well known is that many of these ingredients are currently extracted from their botanical sources using an energy-intensive, dirty industrial process that requires the heavy application of industrial solvents such as ethanol, methanol, ethyl acetate and others.

Even organic products are not immune and, although it should be said that not all ingredients are extracted using industrial processes, there need only be one of these ‘dirty’ ingredients present in the final product to compromise a carefully developed ‘natural’ or ‘organic’ brand reputation.

Another problem with using traditional solvent-based extraction processes is that some of these solvents can be toxic and/or highly flammable. This means they must be handled carefully during the extraction process and in accordance with strict government-mandated environmental procedures.

Such procedures are prone to circumvention, sometimes resulting in dangerous working conditions at solvent extraction facilities either at home or abroad. After use, their disposal presents an environmental challenge because the processed biomass is contaminated with the solvent.

There is also the concern that residual amounts of these solvents may remain in the extracted ingredients and therefore be present in the final consumer products. This is all problematic for many food and beverage manufacturers that advertise natural ingredients, and indeed for any product that includes botanical ingredients.

Given consumers’ rising demands for foods that are clean-label and made using natural ingredients and processes, a more environmentally friendly way of extracting botanical ingredients would certainly be welcomed by the food manufacturing industry globally. Today, just such an advance toward greener, more fully natural ingredients would create a stir in the extraction industry.

Pressurised Water-Based Extraction

Pressurised Water Based Extraction

One such solution was found by extraction scientist Dr Giuseppe (Joe) Mazza who founded Canadian company Mazza Innovation. Together with Dr Carl Pronyk and Dr Eduardo Cacace, they created and patented an innovative, green process to recover high-value bioactives from plants.

This pressurised water-based extraction technology changes the solubility properties of water so that it behaves like an organic solvent in terms of its ability to efficiently extract valuable plant compounds. The process eliminates the numerous drawbacks associated with the use of traditional industrial solvents.

Called the PhytoClean method, this process is able to extract high-quality, solvent-free botanical ingredients and bioactive compounds—including polyphenols, alkaloids, glycosides and specialty carbohydrates—that are of significant value and use to the food and beverage, supplement and personal care and cosmetic industries. Almost any ingredient that comes from a non-oil-based botanical source can be extracted efficiently and cost-effectively.

Standardised to deliver high concentrations of bioactive ingredients and yet free of any carriers or trace industrial solvents, clean ingredients extracted using this process could possibly make older, solvent-based extraction processes obsolete.

The Science Behind The Process

Unfortunately for botanical ingredient extraction, water has always been a generally poor solvent for separating valuable organic molecules from raw biomass; that is why industrial solvent processes were developed in the first place.

For an organic molecule to be dissolved by water, it must ‘compete’ with the hydrogen bonds that already exist between the water molecules. Hydrogen bonds are responsible for many of water’s unusual properties, including, for example, its relatively high surface tension and high boiling point. Since industrial solvents do not have this strong hydrogen bond problem, they are much more effective at dissolving target compounds.

The achievement of the technology is in making water perform like a solvent with respect to the dissolution capacity of organic molecules. Once the water is heated, the kinetic energy of the heated water molecules increases, thus improving the solubility of compounds—i.e. the targets of the extraction. The key, however, is to maintain the water in a liquid state through the use of pressure, even though it is above its atmospheric boiling point of 100 deg C.

Furthermore, by adjusting the temperature (and thus the water’s solubility), it is possible to selectively target certain compounds for extraction while excluding others. Another advantage is that the process includes a built-in ‘kill step’ to lower micro-organism counts for food, cosmetics and supplement products.

In essence, the technology makes water perform as well as (and often better than) than some industrial solvents, but without any of the many negative downsides involved in using solvents. Moreover, since the biomass spends only minutes at elevated temperatures in a purged and closed system, heat-sensitive compounds can be extracted successfully.

The extraction processor produces an initial extract of approximately 1-3 percent solids in purified water. Subsequently, an evaporator is used to remove most of the water. After that, a drying technology called refractance window drying is employed.

This approach to drying the solids is extremely gentle and preserves the extract’s bioactive content and viability. This processing step removes the remaining moisture in the extract and produces a dry, highly concentrated final product that can be ground to meet customers’ specific needs.

The company’s commercial extractor can process 1,000 kg (dry weight) per day of biomass with an acceptable input moisture of 0-90 percent and a minimum particle size of 1-3 mm. It has a footprint of approximately 15 sq m, with five columns that operate sequentially or semi-continuously.

In comparison to conventional techniques, this pressurised water extraction process eliminates the need for multiple environmental certifications and uses a common material handling process. It also improves operator safety (since no flammables are involved), produces usable by-products with limited waste, and is environmentally friendly (figure 1).

More recently, due to rapid growth in customer demand for its processing services, the company has constructed a second extractor processing unit, more than doubling its production capacity. Additional production capability is planned and extractor sales to customers are also occurring.

Traceability And GMP-Registered

Another emerging aspect of the clean-label movement for food and beverage manufacturers is supply-chain visibility, traceability and transparency for the ingredients they purchase from suppliers, both locally and overseas.

The process is able to successfully extract from whole raw biomass—that has not yet been dried and ground up— helping with initial identification and verification of the raw material being processed while it is still in a state to be identified visually. Traceability is also an important need for clean-label manufacturers, and this process enables a high degree of traceability. This delivers the full supply-chain transparency increasingly being demanded by both product manufacturers and consumers.

The process is used in a GMP registered facility and is fully compliant with the quality requirements of dietary supplements and natural health product manufacturers. It has also achieved organic certification under the US, Canadian, European and Japanese organic regimes. And, since this innovative extraction process uses only water as its solvent, no costly solvent handling environmental safety permits or explosion-proof equipment were needed in its design and construction. This translates into competitive pricing for the ingredients and contract processing services it provides to customers.

Food Manufacturers Demanding Solvent-Free Ingredients

Existing technologies leave food and beverage producers with poor choices. As mentioned, organic solvent extraction can yield products that contain residues of highly toxic solvents. Operating safely with organic solvents also requires complicated, expensive physical and regulatory infrastructure.

A further and very important concern is that some extracting companies may not be meeting current environmental standards for minimising solvent residuals in the extracted botanicals, or in handling and disposing of solvents properly.

If manufacturers desire an ingredient that is free of solvent residue, they must rely on either low-performing water extraction or expensive, complicated supercritical carbon dioxide extraction. This extraction technology provides an alternative: a cost-effective process for the extraction of industrial solvents without any of their inherent drawbacks.

Looking Ahead

There continues to be ongoing concerns in the global ingredients marketplace about the ability of traditional solvent-based extraction methods to deliver clean-label products of high quality. With processes such as these, manufacturers can create the fully natural, clean-label products being demanded by consumers.

This means it is full steam ahead for food and beverage producers to pursue a new set of next-generation, solvent free standards for the manufacture of countless products that make use of botanical ingredients.