Field Bean Protein Isolate Production via Air Classification
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Solution Overview
Problem
Conventional methods for producing field bean protein isolates result in a dark color due to tannins and polyphenols, and high solubility at pH values above 7, limiting their industrial applications, especially in bakery and pastry uses.
Innovation Solution
A method involving grinding field bean seeds using a stone mill, separating fractions by ascending air flow, and subsequent grinding with a knife and roller mill, followed by suspension in an aqueous solvent at pH 6-8, centrifugation, isoelectric precipitation, and pH neutralization to produce a protein composition with a light color (L* > 70) and reduced solubility (<25% at pH > 7).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional alkaline extraction and isoelectric precipitation methods are used, then protein isolate is obtained with high protein content (≥80%), but the product has dark gray or black color due to tannins and polyphenols from external fibers
Solution Approach 1:
The patent applies preliminary dehulling action before extraction to remove external fibers containing tannins and polyphenols. The method includes grinding field beans and separating the external fiber fraction prior to alkaline extraction, preventing these harmful substances from being extracted along with proteins, thus avoiding dark coloration in the final product
Solution Approach 2:
The patent extracts and removes the external fiber fraction separately from the cotyledons through grinding and air classification. This separation allows the subsequent extraction process to obtain proteins without co-extracting tannins and polyphenols that would cause dark coloring, while still maintaining high protein content in the isolate
2Reliability
If conventional alkaline extraction and isoelectric precipitation are used, then protein isolate achieves excellent aqueous solubility (>60% at pH 7), but this high solubility becomes a disadvantage for bakery and pastry applications
Solution Approach 1:
The patent modifies the pH parameter throughout the process: maintaining alkaline conditions (pH 8-9) during extraction to ensure high protein solubility and recovery, then adjusting to isoelectric pH (3-5) for precipitation. This parameter control allows optimization of both solubility during processing and reduced solubility in final applications where lower solubility is desired
3Object-affected harmful factors
If optimized dehulling methods with multiple grinding steps, filtering, and turbo-separation are applied to remove tannins and polyphenols, then the color of protein isolate is improved, but the process complexity and cost increase significantly
Solution Approach 1:
The patent performs preliminary grinding and air classification to separate external fibers before extraction. This single preliminary separation step, rather than multiple subsequent filtration and separation steps, effectively removes the source of tannins and polyphenols, simplifying the overall process while achieving good color results
Solution Approach 2:
The patent uses air classification (pneumatic separation) to separate the external fiber fraction from the cotyledons based on density differences. This pneumatic method is simpler and more efficient than multiple mechanical filtration steps, reducing process complexity while effectively removing harmful substances
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 method effectively reduces the content of external fibers and tannins, achieving a light-colored field bean protein isolate with low solubility at high pH values, enhancing its usability in various industrial applications, including human and animal nutrition, cosmetics, and pharmacy.
Implementation Method 1
separating the obtained ground material into two fractions referred to as light and heavy by means of an ascending air flow
Implementation Method 2
Isolating by precipitation by heating at the isoelectric pH of the field bean proteins contained in the liquid fraction
Implementation Method 3
Isolating by precipitation by heating at the isoelectric pH
Implementation Method 4
Removing the dry matter fractions from the suspension by centrifugation
Data Source
AI summary
The invention relates to the field of plant protein isolates, and in particular to field bean protein isolates and such an isolate, the solubility of which is less than 25% at a minimum pH of 7. The invention also relates to a method for the production thereof and to industrial applications thereof.