Stevia Purification Process for Bitterness Removal
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Solution Overview
Problem
Current 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 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
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 that cause residual bitterness and unpleasant aftertaste
Solution Approach 1:
The purification process is divided into multiple sequential stages: initial extraction, treatment with calcium hydroxide to remove impurities, treatment with iron chloride for further purification, deionization, ultrafiltration, and alcoholic precipitation. Each stage targets specific impurities and progressively increases purity to at least 98%, eliminating bitterness and aftertaste while maintaining manufacturing feasibility
Solution Approach 2:
Chemical intermediaries are introduced to facilitate purification: calcium hydroxide is used to precipitate acidic impurities, iron chloride removes tannins and other contaminants, deionization resins eliminate ionic impurities, and alcohol serves as a precipitating agent for the final purification step. These intermediaries enable high-purity product recovery without excessive process complexity
2Manufacturing precision
If multiple purification steps are implemented to achieve high purity, then bitterness and aftertaste are reduced, but the manufacturing process becomes more complex and costly
Solution Approach 1:
Multiple purification functions are combined into an integrated process flow where each step builds on the previous one. The calcium hydroxide treatment, iron chloride treatment, deionization, ultrafiltration, and alcoholic precipitation are merged into a sequential process that achieves cumulative purification effects, reaching at least 98% purity while avoiding redundant operations
Solution Approach 2:
The process exploits parameter changes at each stage: pH adjustment during calcium hydroxide treatment to precipitate impurities, temperature control during iron chloride treatment, ionic exchange capacity during deionization, molecular weight cutoff during ultrafiltration, and solvent polarity changes during alcoholic precipitation. These parameter variations enable selective purification without requiring overly complex equipment
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 sweeteners.
Implementation Method 1
water extraction of dried Stevia leaves
Implementation Method 2
water extraction of dried Stevia leaves
Implementation Method 3
treatment with calcium hydroxide and iron chloride
Implementation Method 4
ultrafiltration
Implementation Method 5
alcoholic precipitation to achieve high purity
Data Source
AI summary
Highly purified Stevioside, Rebaudioside A and a purified sweet steviol glycoside mixture 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.