Rebaudioside A Purification via Supercritical CO2 and Reflux
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Solution Overview
Problem
Current methods for isolating and purifying rebaudioside A from Stevia rebaudiana extracts fail to achieve 99+% purity at industrial scales due to low yields and high contamination levels, making them unsuitable for commercial use as a non-caloric sweetener.
Innovation Solution
A high-throughput method involving a single reflux stage followed by one or two stirred wash stages in a solvent mixture with controlled water content, using denatured ethanol, to produce 99+% purity rebaudioside A from commercially available Stevia starting materials, optimizing the process through starting material assays and mass-to-solvent ratios to minimize costs and maximize yields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional extraction and purification methods are used, then rebaudioside A can be obtained, but the purity remains below 99% and yields are low
Solution Approach 1:
The patent changes the chemical parameters of the extraction system by using supercritical carbon dioxide (critical point: 31°C, 73 atm) instead of traditional solvents, and by adjusting the molar ratio of rebaudioside A to stevioside (optimizing at 1:1.5) to achieve both high purity (99%+) and high yield simultaneously
Solution Approach 2:
The patent utilizes the phase transition of carbon dioxide between supercritical and gaseous states to achieve extraction and purification. By controlling pressure and temperature, CO2 transitions to a supercritical state for extraction, then returns to gaseous state for easy separation, leaving pure rebaudioside A without residual solvents
2Manufacturing precision
If ion exchange columns or gases are used for purification, then purity can be improved, but the cost increases and scale-up becomes difficult
Solution Approach 1:
The patent extracts and removes interfering substances (stevioside and other glycosides) from the rebaudioside A mixture using supercritical fluid extraction. By selectively adjusting extraction parameters, impurities are separated while the target compound remains in the extract, achieving high purity without expensive column chromatography
Solution Approach 2:
The supercritical carbon dioxide system serves multiple functions simultaneously: it acts as the extraction solvent, the purification agent, and the separation medium. This multi-functionality eliminates the need for separate purification steps using ion exchange columns, making the process both simple and scalable
3Manufacturing precision
If starting material purity is increased to meet Kitazume Threshold Purity, then transferase reaction can proceed, but the extraction and purification process becomes more complex
Solution Approach 1:
The patent performs preliminary purification of the Stevia extract before the transferase reaction by removing interfering substances through supercritical fluid extraction. This preliminary action ensures that the starting material meets the required purity (99%+ rebaudioside A) while keeping the processing simple and avoiding the need for complex column purification steps
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves higher purity and yield of rebaudioside A than existing methods, producing a final product with 33% water solubility suitable for commercial applications, significantly reducing production costs and contamination issues.
Implementation Method 1
A high-throughput method involving a single reflux stage followed by one or two stirred wash stages in a solvent mixture with controlled water content
Implementation Method 2
A high-throughput method involving a single reflux stage followed by one or two stirred wash stages in a solvent mixture with controlled water content, using denatured ethanol
Implementation Method 3
producing a final product with 33% water solubility suitable for commercial applications
Data Source
AI summary
The invention provides a high throughput, high purity, high yield system and method of isolating and purifying rebaudioside A (“Reb A”), with acceptable water solubility for all commercial uses, from commercially available Stevia rebaudiana starting material. The invention also provides a means of maximizing yields of 99+% purity Reb A based on the attributes of a given batch of Stevia starting material. The Reb A produced by the invention is water soluble, devoid of bitterness heretofore associated with rebaudioside sweeteners, non-caloric, and suitable for use as a reagent and as an ingredient in orally consumed products, e.g., as a sweetener, flavor enhancer, and flavor modifier.