Oleogels Based on Chickpea Protein Fractions–Xanthan Gum Complexes: Preparation and Characterization

This study investigated the mechanism by which different fractions of chickpea protein influenced the formation of oleogels. Total chickpea protein (CPP, 0.5 wt%), chickpea albumin (ALB, 0.5 wt%), globulin (GLO, 0.5 wt%), and glutelin (GLU, 0.5 wt%) were separately used as oleogelators by combining with xanthan gum (XG, 0.5 wt%) at pH 7 to construct soybean oil-based oleogels via the emulsion-templated method. Particle size measurement revealed that the GLU-XG (526 nm) exhibited the smallest particle size compared to CPP-XG (605 nm), ALB-XG (642 nm), and GLO-XG (819 nm). The four complexes exhibited increasing surface hydrophobicity and conformational flexibility (as revealed by fluorescence spectroscopy) in the order of GLO-XG < ALB-XG < CPP-XG < GLU-XG. Compared with other complexes, the higher surface hydrophobicity, smaller particle size, and more flexible structure of GLU-XG conferred a superior surface activity. Consequently, the fabricated emulsion demonstrated a smaller droplet size (13.91 μm) and enhanced centrifugal stability (94.64%). The confocal laser scanning microscope images confirmed that the oleogel based on GLU-XG exhibited the most uniform and densest network, leading to the highest oil-binding capacity (98.7%) and storage/loss modulus, followed by those based on CPP-XG (97.2%), ALB-XG (95.6%), and GLO-XG (93.9%). This research provides a theoretical basis for using chickpea protein in oleogel formulations and enhances understanding of the structural and interfacial properties of these protein fractions.