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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Small Grain and Food Crops Quality Research » Research » Research Project #445025

Research Project: PCHI: Improving Extraction Yield, Purity, and Functionality of Proteins from Pulse Grains using Enzyme-Assisted Green Extraction

Location: Small Grain and Food Crops Quality Research

Project Number: 3060-21650-002-051-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Sep 1, 2023
End Date: Dec 31, 2025

The objectives of this research are to (1) Determine the amount and type of crude fibers in in-house prepared pulse flour and protein isolates; (2) Evaluate the biodegradation of each crude fiber component upon enzyme hydrolysis; (3) Establish the tuned enzymatic strategies to effectively decompose crude fibers in different pulse flours; (4) Develop the combined enzyme strategies as if the application of a single enzyme is insufficient to improve the extraction yield and purity of the protein; and (5) Comprehensively evaluate the physicochemical properties, including solubility, foaming, and emulsification properties, as well as aromatic profile of the pulse proteins prepared with crude fiber hydrolytic enzymes.

Yellow pea, lentil, and chickpea flours will be prepared in the Cereal Science program at North Dakota State University. The chemical composition of each flour, including moisture, ash, crude protein, crude lipid total starch, and total fiber will be analyzed. Three carbohydrolase enzymes, including pectinase, cellulase, and ß-xylanase, will be selected to hydrolyze endogenous non-starch fibers in pulse flours during protein extraction. The activity of the enzymes will be assayed. For enzyme treatment, the impacts of enzyme-to-pulse flour ratio, extraction pH (7.0, 8.0, 9.0, and 10.0), and duration time (1 h, 2 h, 3 h or 4 h) will be investigated at room temperature. The optimum conditions will be selected according to the amount of released reducing sugars. For the optimized enzymes formula, the efficacy will be assessed by adding the optimal ratio of the enzymes into either the alkaline extraction or isoelectric precipitation step. The enzyme strategy will be optimized by comparing the extraction performance, properties, functionalities, and aroma profiles of pulse proteins prepared with these two steps. The structural changes of proteins will be determined by size separation, surface hydrophobicity, and intrinsic fluorescence analysis. Zeta potential, particle size, surface morphology of pulse protein solution will also be characterized. The functionality of proteins, including absolute solubility, emulsification properties and foaming will be examined. The aroma profile of pulse proteins will be assessed with Agilent Technologies 7890B GC system and 5977A mass detector. Database and standards will be used for identification of compounds according to their mass spectra. Total ion counts will be used for quantifying the amounts of compounds.