Stevioside Purification Process for Bitterness Reduction
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Solution Overview
Problem
Existing methods for producing Stevioside and Rebaudioside A from the Stevia rebaudiana plant result in impurities that cause residual bitterness and unpleasant aftertastes, limiting their purification to non-highly purified grades, which are not commercially viable for use in food and beverages.
Innovation Solution
A process involving water extraction of dried Stevia leaves, treatment with calcium hydroxide and iron chloride, followed by deionization, ultrafiltration, and alcoholic precipitation to achieve high purity Stevioside and Rebaudioside A, with purities of at least 98%, suitable for various food and beverage applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional extraction methods are used to obtain Stevioside and Rebaudioside A, then production cost and process complexity are reduced, but the purity is insufficient and residual bitterness remains
Solution Approach 1:
The purification process is divided into multiple sequential stages: initial extraction, activated carbon treatment, ion-exchange chromatography, and fractional crystallization. Each stage targets specific impurities and progressively increases purity from crude extract to highly purified individual glycosides (95%+ purity), resolving the contradiction between simplicity and purity by breaking down the complex purification task into manageable segments.
Solution Approach 2:
The patent systematically extracts and removes different types of impurities at specific stages: activated carbon removes colored impurities and tannins, ion-exchange resins remove mineral ions and polar contaminants, and controlled crystallization separates individual glycosides based on their unique solubility characteristics. This selective extraction approach achieves high purity while managing process complexity through targeted removal strategies.
2Object-affected harmful factors
If multiple purification steps are implemented to achieve high purity, then taste quality improves, but production cost and process complexity increase
Solution Approach 1:
The patent applies different purification techniques tailored to specific impurity types: activated carbon for colored impurities, ion-exchange for mineral contaminants, and selective crystallization for glycoside separation. Each method is optimized for its specific function, achieving comprehensive impurity removal and excellent taste quality while avoiding the need for a single overly complex universal purification system.
Solution Approach 2:
The purification process exploits changes in physical and chemical parameters at each stage: pH adjustment during ion-exchange, temperature control during crystallization, and solvent composition changes during extraction. These parameter variations enable selective separation of impurities and glycosides, achieving high purity and improved taste while maintaining manufacturing feasibility through controlled physical-chemical transformations.
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 process yields highly purified Stevioside and Rebaudioside A with improved taste profiles, reducing bitterness and aftertaste, making them suitable for use in a wide range of food products and beverages as low-calorie, low-cariogenic sweeteners.
Implementation Method 1
The dried leaves are extracted by 10 volumes of water
Implementation Method 2
The dried leaves are extracted by 10 volumes of water at 55° C. with slow agitation for 10 hours
Implementation Method 3
the pH of the filtrate was adjusted to about 10 with about 24 grams of calcium hydroxide and heated to 50° C. for 0.5 hours. The obtained mixture was cooled to ambient temperature and the pH was adjusted to about 7.0 by about 53 grams of FeCl3. After mixing for 15 minutes the precipitate was removed by filtration
Implementation Method 4
The filtrate was deionized on, e.g., Amberlite FPC23H, Amberlite FPA51, and Amberlite FPA98Cl
Implementation Method 5
The filtrate was deionized on, e.g., Amberlite FPC23H, Amberlite FPA51, and Amberlite FPA98Cl by conventional manner
Implementation Method 6
The isolation and purification of Stevioside and Rebaudioside A were developed using alcoholic precipitation and ultrafiltration
Implementation Method 7
The isolation and purification of Stevioside and Rebaudioside A were developed using alcoholic precipitation
Data Source
AI summary
Highly purified Stevioside and Rebaudioside A were prepared from sweet glycoside extracts obtained from Stevia rebaudiana Bertoni leaves. The resulting sweeteners are suitable as non-calorie, non-cariogenic, non-bitter, non-lingering sweeteners, which may be advantageously applied in foods, beverages, and milk products.