INHIBITION OF BROWNING OF HARVESTED HEAD LETTUCE

Treatments to control browning of lettuce stem discs (cv Iceberg) were evaluated by measuring changes in the L, a* and b* parameters as wel l as Hue angle values. Cysteine, resorcinol, EDTA and citric acid prev ented discoloration. Different concentrations of organic acids (citric , acetic and gluconic), vinegar and lemon juice were also tested. The best results were obtained when the discs were treated with 10 mL/L an d 50 mL/L acetic acid solutions and vinegar. These treatments were the n applied to bead lettuces and browning was measured during 7 days sto rage at 2 degrees C plus an additional commercialization of 3 days at 13 degrees C. Vinegar and 50 mL/L acetic acid solution inhibited brown ing on lettuce stem cuttings and could be used to prevent lettuce butt discoloration during cold storage and commercial handling.