Fractionation of pea flour components using continuous and discontinuous density gradient centrifugation

• Published in: Separation science and technology Vol. 60; no. 12; pp. 1630 - 1641
• Main Authors: Paul, Anjaly, Ekaette, Idaresit, Michel, Ana, Ngadi, Michael
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 13.08.2025
• Subjects: biocompatible polymer; Buoyant density; Iodixanol; plant protein; starch
• ISSN: 0149-6395; 1520-5754
• DOI: 10.1080/01496395.2025.2512362

Density gradient centrifugation (DGC) has been widely used for biomolecule separation based on their buoyant density. This study investigated the effectiveness of DGC in fractionating pea flour into starch- and protein-enriched fractions using three density gradient media (DGM) - polyvinylpyrrolidone (PVP), Optiprep, and corn syrup - applied as a continuous Optiprep gradient and five discontinuous gradients by layering different DGM. DGC was performed using 5 g of pea flour in 10 ml of DGM at 14,000 x g for 10 min. DGC achieved a clear fractionation of pea flour into top and bottom fractions, with 80-90% product recovery. The bottom fractions exhibited higher bulk and tapped densities than the top fractions, indicating successful density-based separation. Compositional analysis confirmed that starch was concentrated in the bottom fractions, while the top fractions were protein rich. The PVP-Optiprep-corn syrup gradient achieved three layered fractions with 71.83% starch (dry basis) in the middle fraction and 36.84% protein (dry basis) in the top fraction. Scanning electron microscopy also confirmed distinct starch granules in the bottom fractions and protein-starch aggregates in the top fractions. This study demonstrates the potential of DGC as a sustainable method for pea flour fractionation, offering an alternative to conventional starch and protein isolation techniques. Density gradient centrifugation separated pea flour into three fractions. Separation was based on the flour particle size and chemical composition. Dense-bottom fractions are starch-rich, while light-top fractions are protein-rich.