ABSTRACTPeroxidase activity was determined in haricot seed prior to germination, 5 days after germination, after 50 days of development and in the mature succulent green bean (80 days after germination). Specific activity of peroxidase, expressed as μ‐mole oxidized o‐dianisidine/mg protein/min, was low (38.2) before germination; it increased substantially after 5 days of germination (90.1) and then increased dramatically with development (50 days, 189.7), followed by a decrease with time to maturity (55.0). Blanching treatment denatured peroxidase and this resulted in the immediate loss of 98% of its activity; 20% of the original enzyme activity was restored when blanched seed was stored for 12 months at −18°C. Peroxidase activity increased slightly in the unblanched seed after 12 months of freeze‐storage at −18°C. Peroxidase activity was also regenerated dramatically when frozen seed was held at room temperature. Freeze‐drying inactivated peroxidase whereas air‐drying showed limited inactivation of this enzyme.