Stevioside Purification Process Using Calcium Hydroxide and Iron Chloride
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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, limiting their purification to non-highly purified grades, which are not suitable for commercial 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 use in various food products and beverages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional extraction and purification methods are used, then production cost and process simplicity are maintained, but the purity of Stevioside and Rebaudioside A is insufficient (below 98%), resulting in residual bitterness and unpleasant aftertaste
Solution Approach 1:
The purification process is divided into multiple sequential stages: initial extraction, filtration through diatomaceous earth, ion exchange chromatography, and crystallization. Each stage targets specific impurities and progressively increases purity, transforming a single complex step into manageable segments that collectively achieve 98%+ purity.
Solution Approach 2:
Ion exchange resins and diatomaceous earth are introduced as intermediary materials to facilitate separation. These intermediaries selectively bind to impurities (proteins, tannins, colored substances) while allowing Stevioside and Rebaudioside A to pass through or be selectively eluted, enabling high-purity separation without direct complex processing of the crude extract.
2Object-affected harmful factors
If multiple purification steps are implemented to achieve high purity, then taste quality is improved, but production time and process complexity increase
Solution Approach 1:
The crude extract undergoes preliminary filtration through diatomaceous earth and ion exchange resin before main purification. This preliminary action removes bulk impurities (proteins, tannins, colored substances) early in the process, reducing the burden on subsequent purification steps and enabling faster achievement of high purity without excessive time investment.
Solution Approach 2:
The process utilizes phase transitions including adsorption (impurities binding to resin/diatomaceous earth), elution (purified compounds being washed out), and crystallization (pure Stevioside and Rebaudioside A forming crystals from solution). These phase transitions naturally separate components based on their physical-chemical properties, achieving high purity through physical rather than time-consuming chemical processes.
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 Stevioside and Rebaudioside A with improved taste profiles, achieving high purity and enhanced sensory characteristics, making them suitable for commercial use as sweeteners in diverse food and beverage applications.
Implementation Method 1
treatment with a base such as calcium hydroxide and then iron chloride
Implementation Method 2
The concentrate is then passed through an ultrafiltration membrane
Implementation Method 3
alcoholic precipitation to achieve high purity Stevioside and Rebaudioside A
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.