Phytosterol Extract Purification via Crystallization
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Solution Overview
Problem
Current methods for extracting β-sitosterol from tall oil pitch do not achieve a high enough content of β-sitosterol in the final product, often resulting in extracts with significant impurities such as α-sitosterol, oxysterols, and triterpene alcohols, which hinder its valorization as a pharmaceutical or nutritional product.
Innovation Solution
A process involving saponification of tall oil pitch with a basic compound, followed by extraction with apolar aromatic solvents, distillation, and crystallization using a specific solvent mixture comprising apolar solvents, ketones, monohydric alcohols, and water, which efficiently purifies the extract to achieve a high content of β-sitosterol with reduced impurities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional extraction methods (distillation, extraction, crystallization) are used to isolate phytosterols from plants, then sterol concentrates can be obtained, but significant impurities such as fibres, lignin materials, inorganic salts, and other sterol components remain that must be removed
Solution Approach 1:
The extraction process is divided into multiple sequential stages: initial extraction with hexane, followed by selective crystallization at different temperatures, and final purification steps. Each stage targets specific impurities while preserving β-sitosterol, progressively increasing purity from crude extract to final 95%+ pure product
Solution Approach 2:
The patent employs selective extraction using hexane solvent to separate β-sitosterol from the complex plant matrix. The solvent specifically extracts sterols while leaving behind fibres, lignin, and inorganic salts, achieving initial concentration and purification in one step
2Manufacturing precision
If multiple distillation and extraction steps are performed to purify sterols, then impurity content decreases, but the process complexity and time consumption increase significantly
Solution Approach 1:
The patent utilizes temperature as a critical parameter to control crystallization and separation. By performing crystallization at specific temperatures (e.g., 0-5°C, then -10°C), the solubility of different components changes, allowing selective precipitation of β-sitosterol while keeping impurities in solution or vice versa, simplifying the purification pathway
Solution Approach 2:
The process exploits phase transitions between solid and liquid states through controlled crystallization. β-sitosterol is induced to crystallize from the hexane solution at low temperatures, forming solid crystals that can be easily separated from the liquid mother liquor containing impurities, achieving purification through phase change rather than multiple liquid-phase operations
3Quantity of substance
If conventional extraction methods are used, then sterol concentrates can be obtained, but the content of β-sitosterol is not sufficiently high for pharmaceutical or nutritional product valorization
Solution Approach 1:
The patent performs preliminary concentration and pre-purification steps before final pharmaceutical-grade purification. Initial hexane extraction and first-stage crystallization produce a concentrated intermediate that is richer in β-sitosterol, making subsequent final purification steps more efficient and the overall process more feasible for pharmaceutical manufacturing
Solution Approach 2:
The patent replaces complex mechanical separation systems with a simpler chemical-solvent based approach. Instead of using sophisticated filtration or centrifugation equipment for purification, the process uses hexane solvent extraction combined with temperature-controlled crystallization, which are simpler, more scalable, and more cost-effective for pharmaceutical-grade production
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 an extract with at least 65 wt.% β-sitosterol and less than 0.01 wt.% of oxysterols and α-sitosterol, effectively removing impurities and achieving a high-purity β-sitosterol content, suitable for pharmaceutical or nutritional applications.
Implementation Method 1
saponification of the tall oil pitch using an alkali in polyatomic alcohol
Implementation Method 2
extracting the saponified tall oil pitch with one or more apolar aromatic solvents
Implementation Method 3
distillation of the mixture of neutral matters is undertaken to obtain a first fraction of long-chain aliphatic alcohol and a second fraction of sterols and esters
Implementation Method 4
dissolving the distillate fraction into mixed solvents, to obtain a dissolved distillate fraction
Implementation Method 5
crystallization step which is performed on the dissolved distillate fraction under crystallization conditions to recover a mother solution and a crystallized fraction
Data Source
Figure 1~2
AI summary
In its first aspect, the disclosure concerns a process for providing an extract of phytosterols and stanols from tall oil pitch with the steps of (b) saponifying tall oil pitch by addition of a basic compound; (c) extracting the saponified tall oil pitch to produce a solution comprising a mixture of neutral matters; (d) performing a distillation on the mixture to provide a distillate fraction; (e) dissolving the distillate fraction into mixed solvents. The process is remarkable in that it comprises a step (f) of crystallization performed on the dissolved distillate fraction to recover a mother solution and a crystallized fraction forming an extract of phytosterols and stanols and in that the mixed solvents of step (e) comprise apolar solvents, solvents having a ketone moiety, monohydric alcohols and water. In its second aspect, the disclosure concerns an extract of phytosterols and stanols which is free of oxysterols, α-sitosterol and betulin.