Low-pH induced structural changes, allergenicity and in vitro digestibility of lectin from black turtle bean (Phaseolus vulgaris L.)

•Lectin of black turtle bean were incubated in acidic buffers for various times.•A steady state of lectin tertiary structure was formed by low pH treatment for 8 h.•Low pH treatment could cause structure alterations significantly and dissociation.•Allergenicity and digestibility of lectin were reduced by low-pH induced process. Lectin was incubated in corresponding acidic buffers (pH 1.0–3.5) for a certain period (0.5, 1, 2, 4, 8, 12 and 24 h) at 25 °C. Low-pH induced changes in structure, allergenicity and in vitro digestibility of lectin from black turtle bean (Phaseolus vulgaris L.) were investigated in the present study. Results indicated that the alteration in structure was a progressive unfolding process mainly depending on pH environment, and the treated lectin attained a stable state at 8 h. Electrophoretic, dynamic light scattering (DLS) and size exclusion chromatography (SEC) analyses suggested that lectin monomers appeared in the solutions of pH