Expanded snacks were manufactured entirely from pea flour using a twin-screw extruder operated at moisture content ranging [18; 26%], temperature [120; 170°C] and specific mechanical energy [500; 1200 kJ/kg]. All pea snacks, extruded using different operating conditions and die geometries, were expanded radially. Some snacks, that exhibited either maximum longitudinal expansion index or maximum radial expansion index on an anisotropy map, were selected for other analyses: protein solubility reflecting protein cross-linking amount by disulphure bonds, X-ray tomography (foam density, cellular structure features), CSLM (morphology of cell wall), DMA (glass transition temperature Tg and elasticity of molten blends), and compression test (Young’s modulus). Snacks density decreased from 800 to 80 kg/m-3 while extrusion temperature increased, accompanied concomitantly by protein solubility rise. Mean cell size (MCS) and mean cell wall thickness (MWT) of snacks varied between 0.66 and 2.38 mm and between 131 and 512µm, respectively. The more intense the protein aggregations, the higher the Tg and the melt storage modulus (‘melt elasticity’). The benefits are bubbles coalescence and shrinkage are hindered, and overall expansion is increased, accompanied by a higher radial expansion index, larger MCS and thicker MWT. The high melt elasticity also suppressed bubbles nucleation inside die, thus longitudinal expansion. All snacks exhibited fragile mechanical behaviour with rupture in the elastic domain. The variation of normalized Young modulus with relative density followed a power law model. The modulus values were dispersed at low density (< 200 kg.m-3) suggesting an important contribution of cellular structure and cell wall morphology on snack texture.