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ARS Home » Southeast Area » New Orleans, Louisiana » Southern Regional Research Center » Food Processing and Sensory Quality Research » Research » Publications at this Location » Publication #398608
Research Project: Biochemical Approach to Protein Processing, Texturization and Nutritionally Beneficial Plant-based Foods

Location: Food Processing and Sensory Quality Research

Title: Protein composition of pulses and their protein isolates from different sources and in different isolation pH using a reverse phase high performance chromatography method

Author
item SADEGHI, ROHOLLAH - University Of Idaho
item COLLE, MICHAEL - University Of Idaho
item Smith, Brennan

Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/19/2022
Publication Date: 5/30/2023
Citation: Sadeghi, R., Colle, M., Smith, B. 2023. Protein composition of pulses and their protein isolates from different sources and in different isolation pH using a reverse phase high performance chromatography method. Food Chemistry. 409. Article 135278. https://doi.org/10.1016/j.foodchem.2022.135278.
DOI: https://doi.org/10.1016/j.foodchem.2022.135278

Interpretive Summary: For alternative proteins, the lack of biochemical consistency creates issues with processing and final quality of texturized vegetable proteins and high moisture meat analogs. Therefore, the objective of this study was to compare the composition of pulse protein isolates made from lentils, green peas, and yellow peas at varying isolation pH values and determine the effect of this variability on protein functionality. For this, each pulse type was extracted at two different pHs (9 and 11). Lentil flour showed the highest level of vicilin with a vicilin to legumin ratio of ~2.5, while this ratio was 1.3 and 1.2 for green and yellow pea flour, respectively. It is generally accepted that higher vicilin to legumin ratios result in stronger protein gels and may provide better extrusion characteristics. Albumin content of yellow pea was high (~36.1%) in flour, but it reduced to ~15-19% in isolated proteins, which shows a loss of albumins during the isolation process. Extraction pH increased protein yield but led to lower protein solubility. No changes in protein foaming properties or in-vitro digestibility for any of the treatments was observed.

Technical Abstract: The objective of this study was to compare the composition of pulse protein isolates made from lentils and green and yellow peas at varying isolation pH values and determine the effect of this variability on protein functionality. For this, each pulse type was extracted at two different pHs (9 and 11). Chromatogram peaks obtained from reverse phase high performance chromatography were identified by isolation of albumin-, vicilin- and legumin-rich fractions for the three pulses. Percentage of each protein class was obtained for each isolate and compared against that of the originating pulse flour. Lentil flour showed the highest level of vicilin with a vicilin to legumin ratio of ~2.5, while this ratio was 1.3 and 1.2 for green and yellow pea flour, respectively. Albumin content of yellow pea was high (~36.1%) in flour, but it reduced to ~15-19% in isolated proteins, which shows a loss in the subfraction during the isolation process. Extraction pH increased protein yield but led to lower protein solubility. No changes in protein foaming properties or in-vitro digestibility for any of the treatments.