Stevia Extraction Using Hot Water and Chromatography
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Solution Overview
Problem
Current stevia extraction methods are complex, costly, time-consuming, and environmentally unfriendly, often requiring organic chemical solvents that are not recommended for human consumption, making it difficult to achieve an organic certifiable stevia extract with high sweetness and purity.
Innovation Solution
A solvent-less extraction method using hot water-based extraction of dried and ground stevia leaves, followed by successive chromatographic purifications with GRAS solvents like water and ethanol, to produce a stevia extract with high sweetness and antioxidant properties, suitable for organic certification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional extraction methods using organic chemical solvents are used, then high purity stevia extract can be obtained, but the process becomes environmentally unfriendly and unsuitable for organic certification
Solution Approach 1:
The patent extracts only the necessary components (stevia glycosides) from the plant material using water, deliberately excluding harmful organic solvents. This selective extraction achieves high purity (90% or more steviol glycosides) while maintaining environmental friendliness and organic certification suitability.
Solution Approach 2:
The patent changes the extraction parameter from organic solvents to water, and optimizes temperature parameters (hot water extraction at elevated temperatures) to achieve high extraction efficiency and purity without requiring harmful chemicals, thus resolving the contradiction between purity and environmental safety.
2Manufacturing precision
If multiple solvents and chemicals are used for extraction and purification, then high sweetness and purity can be achieved, but the process becomes complex, costly, and time-consuming
Solution Approach 1:
The patent removes unnecessary solvents and chemicals from the extraction process, using only water as the extraction medium. This simplification maintains high purity extraction while eliminating process complexity, cost, and time associated with multiple chemical agents.
Solution Approach 2:
Water serves multiple functions in this process: it acts as the extraction solvent, the purification medium, and the final product carrier. This multi-functionality eliminates the need for multiple different solvents and chemicals, simplifying the overall process while maintaining high purity.
3Productivity
If ethanol extraction is used to obtain high sweetness, then extraction efficiency is improved, but the taste profile of stevia extract is adversely affected
Solution Approach 1:
The patent changes the extraction temperature parameter (using hot water at elevated temperatures) to compensate for the lower solubility of steviol glycosides in water compared to ethanol, achieving high extraction efficiency without using ethanol, thus preserving the desirable taste profile.
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 results in a cost-effective, rapid, and less complex process that produces a high-purity stevia extract with at least 90% sweetening compounds, qualifying for organic certification and being amenable to large-scale production.
Implementation Method 1
extracting sweetening compounds from a dried and grinded preparation of stevia leaves by contacting same with at least a first hot extraction solvent being generally recognized as safe (GRAS) to form a crude extraction solution
Implementation Method 2
hot water-based extraction of dried and ground stevia leaves, followed by successive chromatographic purifications
Implementation Method 3
successive chromatographic purifications with GRAS solvents like water and ethanol
Data Source
AI summary
A simple extraction method for preparing an organic certifiable stevia extract with high sweetness and optionally with antioxidant properties is provided. The extraction method involves extraction of stevia leaves that have been dried and grinded with a hot solvent generally regarded as safe (GRAS), allowing the dissolution of the sweetening compounds naturally present therein. These sweetening compounds include steviosides and rebaudioside A, which are purified from the extracts by two or more successive chromatographic purifications steps. The sweetening compounds are then eluted with an appropriate elution solvent. The simplicity and organic certification of the method provide advantages over the methods currently employed in the stevia industry.