Advantanges
  1. Semi-continuous process

  2. Lesser number of process steps.

  3. Lesser number of equipments.

  4. More efficient extraction with less water use

  5. Higher energy efficiency

  6. Less floor space requirement

  7. No separate solvent recovery system required

  8. No costly nanofiltration system

  9. Lower consumable cost

  10. Process based on crystallization and not on spray drying, hence no solvent vapour loss

Resin Free Steviol Glycoside Extraction Technology

I started working on steviol glycoside extraction in 2006 when I was working in Sun Biotechnology Ltd. as Senior Scientist and looking after their industrial enzyme production unit. At that time, very little information was available in public domains on steviol glycoside extraction methods. The Chinese were the only people commercially extracting steviol glycoside back then. I didn’t have any details about the resin technology used by them and thus worked out a process which is entirely different.

 

The process was first developed in Sun Biotechnology Ltd. in lab bench scale and the dried leaves were kindly provided by Medicinal and Aromatic Plant Department of Narendrapur Ramakrishna Mission. Later, the technology was scaled up to pilot level in Innova Biosystems Ltd. Finally, a commercial unit was built in Himachal Pradesh in collaboration with Stanpack Pharma Ltd. with financial assistance from Technology Information Forecasting and Assessment Council (TIFAC), Department of Science and Technology, Government of India.

 

TIFAC released the grant on May 14th, 2008 and constituted a monitoring committee comprising the following personnel –

TIFAC Monitoring Committee

Prof. Deepak Kunjru

M.S., Bucknell University, Ph.D., University of Pittsburgh,

Emeritus Fellow – IIT Kanpur, Department of Chemical Engineering

Mr. Soumitra Biswas 

M. Tech Chem. Eng., IIT Kharagpur

Adviser/Scientist-'G', TIFAC, Dept. of Science & Technology, Govt. of India

Dr. I.P. Singh 

Ph.D., Shizuoka University, Japan & Punjab Agricultural University

Professor, National Institute of Pharmaceutical Education and Research (NIPER)

Prof. Rintu Banerjee

Ph.D.(IIT Kharagpur)

Professor, Agricultural & Food Engineering, IIT Kharagpur

Mr. P.R. Basak,

B.Tech., Chemical Engineering, University, Calcutta University

Head, Technology Innovation Programme at TIFAC, Govt. of India

STANPACK

Representative

Shantanu C

Innovator of the technology

The committee critically assessed the technical feasibility of the process before release of the financial grant. The committee also monitored the establishment of the extraction unit and reviewed its performance in every stage. Finally, the monitoring committee approved the unit for commercial production on May 14th, 2010, after they are satisfied with the process performance. Later, several other organizations adopted the technology for commercial stevia extraction.   

 
Process Description

Dried whole leaves are extracted with hot water in a counter current continuous extractor

The water extract is clarified by electro-coagulation

The moist spent leaves are dewatered with a screw extruder and sent for solid waste disposal

Crude steviol glycoside crystallizes out. It is separated from the mother liquor by centrifugation

Separated mother liquor is sent back in the process

Crude steviol glycoside is either dried in vacuum tray dryer or sent for further purification

Crude steviol glycoside is dissolved in specific alcohol water mixture under refluxing condition and then the solution is cooled to re-crystallize purified steviol glycoside/rebaudioside A

Crystallized purified steviol glycoside is dried in vacuum tray dryer

Steviol glycoside is extracted from the aqueous extract in a continuous countercurrent liquid liquid extraction column with a water immiscible alcohol mixture.  

The alcoholic phase is stripped of all emulsified water by a high-speed disc-stack centrifuge

The moisture free alcoholic phase is passed through a activated charcoal column the remove pigments and impurities

Recovered solvent is recycled in the process

The decolorized alcoholic extract is filtered through sparkler filters

The filtered alcoholic extract is evaporated under reduced pressure in a modified rising film evaporator and the alcohol vapour is recovered by condensing in a heat exchanger cooled by chilled brine.

 
 
Specific Advantages of Individual Unit Processes 
Process Diagram

Water Extraction Stage

Solvent Extraction and Clarification Stage

Vacuum Evaporation and Crystallization Stage

Picture Gallery
First Crystallization
This is a picture of historical importance. This is a sample of crystallized steviol glycoside along with mother liquor from the first production batch
Crystallization
View of crystallized steviol glycoside mixed with mother liquor
Vacuum tray dryer
Vacuum tray dryer is used to dry crystallized steviol glycoside.
Small extraction unit view 1
A view of the first extraction unit
Small extraction unit view 2
A view of the first extraction unit
Small extraction unit view 3
A view of the first extraction unit
Show More
 
 

Report on TIFAC website

Development and optimization of enzymatic process for producing Stevioside from Stevia leaves

Partner : M/s. Stanpack Pharma Pvt. Ltd. at Baddi, Himachal Pradesh

The project aimed at developing know-how and optimizing the process parameters for producing stevioside from stevia rebaudiana leaves. Entire plant and machinery were fabricated, installed and commissioned and the production unit was made operational. The process for producing stevioside from stevia leaves had been successfully optimized in the project. The project progress was closely monitored and reviewed by an Advisory and Monitoring Committee constituted for the project. The project had achieved the targeted milestones and delivered the product after optimizing the process of extraction as envisaged. The project was declared successfully completed by the Advisory and Monitoring Committee in May 2010.

Click on image to visit  TIFAC webpage