Stevia Purification Process for Bitterness Removal
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Solution Overview
Problem
Existing methods for producing Stevioside and Rebaudioside A from the Stevia rebaudiana plant result in impurities leading to residual bitterness and unpleasant aftertaste, necessitating a process for highly purified sweeteners suitable for 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 use in various food products and beverages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional extraction methods are used to produce Stevioside and Rebaudioside A, then the production process is simple and cost-effective, but the product contains impurities causing residual bitterness and unpleasant aftertaste
Solution Approach 1:
The patent applies extraction principles by removing impurities from the steviol glycoside mixture through selective precipitation and filtration processes. Calcium hydroxide is used to precipitate unwanted components, and the mixture is filtered to separate impurities from the desired glycosides, thereby eliminating the harmful bitter taste while maintaining production feasibility
Solution Approach 2:
The patent changes physical and chemical parameters during processing, including adjusting pH levels with calcium hydroxide, controlling temperature during evaporation, and modifying solvent composition. These parameter changes enable selective precipitation of impurities while preserving the sweetness of Stevioside and Rebaudioside A, resolving the contradiction between simple processing and product quality
2Object-affected harmful factors
If multiple purification steps are added to remove impurities and improve taste, then the taste quality improves, but the device complexity and process difficulty increase
Solution Approach 1:
The patent combines multiple purification functions into integrated process steps. For example, calcium hydroxide treatment simultaneously performs pH adjustment, impurity precipitation, and partial purification in one operation. The evaporation and crystallization steps are combined to achieve both concentration and purification, reducing overall process complexity while maintaining high taste quality
Solution Approach 2:
The patent uses calcium hydroxide as an intermediary substance to facilitate purification. This mediator selectively reacts with and precipitates impurities, making them easy to remove through filtration. The intermediary approach simplifies the purification process while effectively improving taste quality by removing bitter compounds
3Ease of manufacture
If traditional purification methods are used, then the production cost is lower, but the purity of Stevioside and Rebaudioside A remains insufficient
Solution Approach 1:
The patent utilizes phase transition principles through controlled evaporation and crystallization. By gradually evaporating the solvent and controlling cooling rates, the desired glycosides crystallize in pure form while impurities remain in solution or precipitate separately. This natural purification through phase changes achieves high purity without requiring expensive advanced separation equipment
Solution Approach 2:
The patent employs parameter changes including temperature control during evaporation, pH adjustment with calcium hydroxide, and solvent composition modification. These controlled parameter changes enable selective crystallization of high-purity Stevioside and Rebaudioside A at each stage, achieving manufacturing precision comparable to expensive methods while maintaining cost-effectiveness
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 effectively removes impurities, resulting in sweeteners with improved taste profiles and enhanced purity, suitable for applications in foods, beverages, and pharmaceuticals, offering a commercially viable solution for producing highly purified Stevioside and Rebaudioside A.
Implementation Method 1
water extraction of dried Stevia leaves
Implementation Method 2
water extraction of dried and powdered leaves
Implementation Method 3
treatment with a base such as calcium hydroxide and then iron chloride
Implementation Method 4
treatment with a base such as calcium hydroxide and then iron chloride
Implementation Method 5
The filtrate was deionized on, e.g., Amberlite FPC23H, Amberlite FPA51, and Amberlite FPA98Cl
Implementation Method 6
isolation and purification of Stevioside and Rebaudioside A were developed using alcoholic precipitation and ultrafiltration
Implementation Method 7
isolation and purification of Stevioside and Rebaudioside A were developed using alcoholic precipitation
Implementation Method 8
The filtrate is concentrated under vacuum and spray dried
Implementation Method 9
The filtrate is concentrated under vacuum and spray dried
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.