Hemp Protein Extraction via pH Shift and Alcohol Precipitation
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Solution Overview
Problem
Current methods for extracting proteins from hemp result in denatured proteins and unpleasant flavor due to the presence of phenolic complexes, leading to low-quality protein products unsuitable for human consumption, with high protein losses and residual oil hindering effective separation.
Innovation Solution
A 5-stage aqueous separation process involving prewashing hemp pressing remnants with water to separate oil and phenolic compounds, followed by alkalization and precipitation using a short-chain alcohol to achieve a high-protein content of over 70% with minimal protein loss and improved sensory properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional extraction processes (alkaline solution with precipitation or ethanolic-aqueous extraction) are used, then protein concentrates or isolates can be obtained, but the proteins are denatured and the product has unpleasant flavor due to phenolic complexes
Solution Approach 1:
The extraction process is divided into multiple sequential stages: initial alkaline extraction to solubilize proteins, followed by acidification to precipitate proteins while leaving phenolics in solution, then centrifugation to separate the precipitated proteins from the phenolic-containing supernatant. This segmentation allows selective removal of harmful phenolic complexes while preserving protein quality.
Solution Approach 2:
The process extracts proteins from hemp press cake using alkaline solution, then separately extracts and removes phenolic complexes through acidification and centrifugation. The phenolic complexes are taken out from the protein matrix and separated into a distinct phase that can be discarded, leaving pure protein concentrate.
2Productivity
If heating to 80°C is applied during extraction, then extraction efficiency is improved, but proteins are partially denatured leading to increased loss
Solution Approach 1:
The process uses moderate temperature extraction (avoiding excessive heating) combined with pH parameter changes to control protein solubility and extraction efficiency. By adjusting pH from alkaline to acidic conditions, the process achieves effective protein recovery without requiring high temperatures that would cause denaturation and loss.
3Object-generated harmful factors
If large quantities of water are used for washing extracted proteins, then sensory properties are enhanced, but protein losses increase
Solution Approach 1:
The process uses acidification as an intermediary step that causes proteins to precipitate out of solution while phenolic complexes remain dissolved. This intermediary chemical transformation allows separation without requiring extensive water washing, as the phenolics are already separated in the supernatant phase during centrifugation.
4Ease of manufacture
If residual oil is present in the raw material, then the starting material is more readily available, but effective separation of proteins from the organic matrix is hindered
Solution Approach 1:
The process changes the pH parameter to alkaline conditions during extraction, which alters the solubility characteristics of both proteins and oils. Under alkaline conditions, proteins become soluble while oils remain as separate phases, enabling effective separation despite the presence of residual oil in the starting material.
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 preserves the gel-forming capacity of hemp proteins, reduces bitterness, and achieves a high protein content with low oil and phenolic residues, resulting in a sensorially acceptable protein concentrate suitable for consumer products.
Implementation Method 1
Prewashing the hemp pressing remnants with the addition of water, with suspension of the hemp pressing remnants to form an aqueous suspension
Implementation Method 2
Extracting proteins by alkalizing the high-protein prewashed phase with resuspension to form an aqueous suspension and separating the phases
Implementation Method 3
Precipitating proteins with the addition of a short-chain alcohol having fewer than four carbon atoms and with the addition of an acid to shift the pH value into the acidic range
Implementation Method 4
Separating the phases, in particular by centrifugal phase separation, into a low-protein phase and a high-protein phase
Data Source
AI summary
Proteins are obtained from hemp by prewashing the hemp pressing remnants with addition of water, with suspension of the hemp pressing remnants to form an aqueous suspension having a pH value <7 and phase separation to form an aqueous low-protein contaminant phase containing oil and/or oil-accompanying products and a high-protein prewashed phase. Proteins are extracted by alkalizing the high-protein prewashed phase with resuspension to form an aqueous suspension and separating the phases to form a shell fraction and an aqueous protein fraction. Proteins are precipitated with the addition of a short-chain alcohol having fewer than four carbon atoms and with an acid to shift the pH value into the acidic range. The phases are separated into a low-protein phase and a high-protein phase.