Methods for making plant protein concentrates
Methods of making food-grade plant protein compositions, including yellow pea protein compositions, are provided. The methods use pulses, such as yellow peas, and flours derived therefrom.
1. A method for making a plant protein composition, the method comprising:
(a) providing an aqueous slurry comprising hydrolyzed water-soluble and water-insoluble pulse proteins;
(b) removing the water-insoluble pulse proteins and other water-insoluble components from the aqueous slurry to provide a water-soluble, protein-rich liquid fraction comprising both hydrolyzed globulin proteins and hydrolyzed albumin proteins;
(c) separating water-soluble pulse proteins in the protein-rich liquid fraction from water-soluble lower molecular weight peptides and water-soluble non-proteins in the protein-rich liquid fraction via ultrafiltration using an ultrafiltration membrane that concentrates hydrolyzed globulin proteins and hydrolyzed albumin proteins in a protein-rich retentate; and
(d) removing water from the protein-rich retentate to provide a dry plant protein composition having a pulse protein concentration of at least 70%, based on a dry weight basis.
2. The method of claim 1 , wherein the water-soluble pulse proteins in the aqueous slurry and in the dry plant protein composition have a degree of hydrolysis of greater than zero percent and less than 15 percent.
3. The method of claim 2 , wherein the water-soluble pulse proteins in the aqueous slurry have a degree of hydrolysis of greater than 1 percent, but no greater than 12 percent.
4. The method of claim 1 , wherein the aqueous slurry comprises from 5 wt. % to 12 wt. % pulse particles, the pulse particles having a maximum particle size of less than 200 microns; and the water-soluble, protein-rich liquid fraction has an insoluble solids content of no greater than 2.0 vol. %.
5. The method of claim 1 , wherein the step of providing the aqueous slurry comprising the hydrolyzed water-soluble and water-insoluble pulse proteins comprises conducting an alkaline proteolytic extraction and hydrolysis on an aqueous slurry of pulse particles.
6. The method of claim 1 , wherein the ultrafiltration membrane has a molecular weight cutoff of 5 kDa or smaller.
7. The method of claim 1 , wherein the pulse proteins comprise yellow pea proteins and the plant protein comprises yellow pea protein.
8. The method of claim 1 , wherein the pulse proteins are selected from chickpea proteins, lentil proteins, fava bean proteins, and mung bean proteins and the plant protein is selected from chickpea protein, lentil protein, fava bean protein, and mung bean protein.
9. The method of claim 1 , wherein the dry plant protein has a solubility of at least 95%.
10. The method of claim 1 , further comprising performing an amylase carbohydrate reaction on the water-soluble, protein-rich liquid fraction after removing the water insoluble proteins and other water insoluble components from the aqueous slurry, but before separating the water-soluble proteins in the protein-rich liquid fraction from water-soluble lower molecular weight peptides and water-soluble non-proteins in the protein-rich liquid fraction.
11. The method of claim 10 , wherein the water-soluble pulse proteins in the aqueous slurry have a degree of hydrolysis of greater than zero percent and less than 15 percent.
12. The method of claim 11 , wherein the water-soluble pulse proteins in the aqueous slurry have a degree of hydrolysis of greater than 1 percent, but no greater than 12 percent.
13. The method of claim 10 , wherein the aqueous slurry comprises from 5 wt. % to 12 wt. % pulse particles, the pulse particles having a maximum particle size of less than 200 microns; and the water-soluble, protein-rich liquid fraction has an insoluble solids content of no greater than 2.0 vol. %.
14. The method of claim 10 , wherein the amylase carbohydrate reaction is carried out on the water-soluble, protein-rich liquid fraction at a pH in the range from 5.0 to 6.0 and results in the conversion of starch, dextrins, maltodextrins, and complex sugars into smaller fragments that pass through into a permeate fraction of the ultrafiltration process.
15. The method of claim 1 , wherein the plant protein composition comprises legumin, vicilin, and convicilin proteins having molecular weights in the range from 20 kDa to 70 kDa and albumin proteins having molecular weights in the range from 1 kDa to 40 kDa.
16. The method of claim 1 , wherein the dry plant protein composition has a pulse protein concentration of at least 80%, based on a dry weight basis.
17. The method of claim 1 , further comprising heat-treating the protein-rich retentate to kill microorganisms, pathogens, or both.
18. The method of claim 1 , further comprising adding the dry plant protein composition to a foodstuff.
19. The method of claim 1 , further comprising adding the dry plant protein composition to a beverage.
20. The method of claim 1 , further comprising mixing the dry plant protein composition with a coloring agent, a flavoring agent, a plant-based oil, vitamins, minerals, preservatives, or emulsifying agents.