Steviol Glycoside Crystallization for Nitrogen Reduction

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Solution Overview

Problem

Current methods for purifying steviol glycosides from fermentation broths result in high nitrogen content, which is undesirable and affects the quality and purity of the final product.

Innovation Solution

A method involving crystallization of steviol glycosides from an aqueous solution at a pH of 7.0 or higher, followed by a recrystallization step in water, significantly reduces the nitrogen content to levels below 800 ppm, ensuring a high-purity steviol glycoside composition with at least 80% dry weight of rebaudioside A, D, or M.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If steviol glycosides are purified from fermentation broths using conventional methods, then the purification process is simple, but the nitrogen content in the final product remains high

Engineering Contradiction:

Improvenitrogen content reductionVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by adjusting pH to 7.0 or higher during crystallization, which fundamentally alters the solubility characteristics of steviol glycosides versus nitrogen-containing impurities. This pH parameter change enables selective crystallization that effectively removes nitrogen while maintaining product yield and quality

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The purification process is segmented into distinct stages: initial concentration of fermentation broth, pH adjustment to 7.0 or higher, crystallization step, and filtration. This segmentation allows each stage to optimize for its specific function, with the crystallization stage specifically targeting nitrogen removal through controlled pH conditions

Inventive Principle:

Principle #1Segmentation

2Quantity of substance

If steviol glycosides are extracted from Stevia plants, then the source material is readily available, but substantial land area and intensive labour are required

Engineering Contradiction:

Improvesteviol glycoside productionVSAvoidcultivation requirements

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical/biological system of Stevia plant cultivation with a fermentative process using microorganisms. This substitution eliminates the need for agricultural land, seasonal cultivation cycles, and intensive manual labor while maintaining high steviol glycoside production. The fermentation process uses controlled bioreactors instead of agricultural fields

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces microorganisms as an intermediary system to produce steviol glycosides. These microorganisms serve as a mediator that converts simple substrates into steviol glycosides through fermentation, replacing the need for complex plant cultivation while providing a controlled, scalable production method

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If steviol glycosides are crystallized from aqueous solution at pH 7.0 or higher, then nitrogen content is reduced to below 800 ppm, but the crystallization process requires precise pH control

Engineering Contradiction:

Improvepurity levelVSAvoidpH control requirements

Core Design Contradiction:

Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent applies preliminary action by adjusting the pH to 7.0 or higher before initiating crystallization. This pre-adjustment ensures that the crystallization environment is optimally prepared to favor the precipitation of steviol glycosides while keeping nitrogen-containing impurities in solution, thereby achieving high purity without requiring complex real-time monitoring during crystallization

Inventive Principle:

Principle #10Preliminary action

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

This process effectively reduces nitrogen levels in steviol glycoside compositions, enhancing their purity and quality, making them suitable for use as high-potency sweeteners with improved sensory properties.

Implementation Method 1

crystallizing steviol glycosides from an aqueous solution comprising steviol glycosides

Methodology Applied

Scientific EffectCrystallization: Crystallisation

Data Source

PatentEP3320104B1Method for preparing a steviol glycoside composition

Publication Date: 2021.11.10 DSM IP ASSETS BV

AI summary

The present invention relates to a composition comprising one or more steviol glycosides which composition comprises nitrogen in an amount of no more than about 1000ppm. The invention also relates to a method for preparing a steviol glycoside composition, which method comprises: providing a steviol glycoside composition; combining the steviol glycoside composition with water to form a steviol glycoside solution; and crystallizing a steviol glycoside composition from the solution. The invention also relates to a method for reducing the nitrogen content of a steviol glycoside composition, which method comprises: providing a steviol glycoside composition which comprises nitrogen; combining the steviol glycoside composition with water to form a steviol glycoside solution; and crystallizing a steviol glycoside composition from the solution, thereby to reduce the amount of nitrogen in the steviol glycoside composition.