Stevia Extraction Technologies and Recent Developments
Scientific and honest information about industrial extraction technologies of stevia are very scarce in public domain. Whenever a person starts looking for basic information about the extraction technology options, he encounters the following things –
Patents documents written in mystic language – which hide more that they reveal
Webpages of technology developers – who often make unjustifiable tall claims and use a lot of marketing jargons
Research papers – Some are legit and others are fakes – but all of them are too technical.
In this webpage, I am presenting a collection of articles on steviol glycoside extraction technology. In these articles, I tried to explain the basics of extraction technology in simple language. It is my humble endeavor for dissemination of honest information for the benefit of all interested readers.
I am now looking for overseas technology partners for jointly working for technology dissemination. The objective for the collaboration will be –
Establishing local single window facilities for technical assistance to Stevia Start Ups
Jointly executing overseas turnkey project
Promotion of location specific appropriate technology
Assimilation of local home-grown technologies and their commercialization.
I am looking forward to establish long-term relationship based on mutual trust and simultaneous growth. If you are interested…….kindly drop a message.
The industrial process of extraction of steviol glycoside is often the least understood aspect in entire value addition chain of Stevia. All the information available in the public domain about the extraction process is either too technical for general audience or infested with overhyped marketing jargon. Let me try to explain the process in detail in simple and straightforward language.
In almost all the industrial technologies for extraction and purification of steviol glycosides, leaves are extracted with water as the first step. Generally, the process involves seeping whole dried leaves with hot water, sometime with agitation, and then separation of the liquid extract from the spent leaves. Most of the time, the economics of the whole extraction and purification process depends on the efficiency of this water extraction process.
We started working on steviol glycoside extraction in 2006. At that time, we worked out a process which is entirely different from the conventional resin based technology. Later, the technology was scaled up to pilot level and finally, a commercial unit was built in Himachal Pradesh financial assistance from Technology Information Forecasting and Assessment Council (TIFAC), Department of Science and Technology, Government of India.
All the extraction process actually yields simultaneously a spectrum of products with different total glycoside content and glycoside profile (i.e. relative percentage of different glycosides). All these products fetch different prices. Thus, to maximize profit, all the production parameters are to be planned in such a way, which maximizes production of products which sale at higher price.
New Methods for Activated Carbon Decolorization in Stevia Extraction
In the extraction and purification process of steviol glycosides has several steps which involve removal of coloured components from liquid extract by activated carbon. Activated carbon treatment is a very delicate unit process which needs proper equipment and precision process control. The conventional Chinese origine extraction process engineering is yet to assimilate the modern methods of activated carbon treatment. Thus, very often the extraction units end up with activated carbon treatment units with primitive design with very low efficiency and high process time.
Let us discuss about some modern activated carbon treatment systems and equipments which may be integrated into the extraction process for higher process efficiency and lower processing cost.
Use of ion exchange resins, chemical flocculating and chelating agents and solvents in the conventional extraction and purification process of steviol glycosides seemed as incompatible to its “natural” and “organic” image to a group of workers. To address these issues, the membrane filtration based extraction technology has been proposed.
The essential features of this technology are as follows –
Apart from water, no other solvent is used in the process
Steviol glycosides are purified only on the basis of physical filtration
Recently, this technology is often being promoted as the “Holy grail” of extraction processes. But, like all other process technologies, it has also its pros and cons. Here, I am trying to “demystify” the process through a simple process description and discussions about its advantages and drawbacks.
For about an year we are anxiously waiting for commercial launch of steviol glycosides produced through fermentation. At least three commercial companies are working on industrial scale production of fermentation derived products.There has been intense interest and competition to commercialize the fermentation based production of steviol glycosides, driven by two key factors.Firstly, possibility of mass producing rare steviol glycosides like Reb M, Reb D etc., which are said to have better taste profile than Reb A, at cheaper cost. Secondly, the prospect of getting those fermentation based steviol glycosides legally described and labeled as “Natural”, which may enable producers to quietly incorporate them in profitable natural products markets.The initiative of developing a production process for stevia sweeteners, which is supposed to make the entire stevia farming sector irrelevant, generated a mixed reaction among the stakeholders. In this article, I tried to provide a commentary on the topic.
Produced by nutrition from earth, rain and sunshine from a plant…….found by ancient wisdom
Produced by a genetically modified organisms in an industrial setup utilizing inorganic/synthetic nutrients
I have started working on a micro-scale Stevia extraction set up. The objective of the work is to standardize a system, which can be accommodated on few tables….but capable of producing steviol glycoside economically. In short, I am trying to break the “scale of economy” barrier. The system is actually a miniaturization of the industrial process, to be used as process modification and standardization platform. For this process, I have worked out the engineering details and standardized the process parameters for an electro-coagulation system for clarification of the water extract. This process does not require use of hazardous chemical flocculants like Calcium Hydroxide, Ferric Chloride of Alums. We are now one more step closer to absolute organic extraction process.