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 well as Hue angle values. Cysteine, resorcinol, EDTA and citric acid prevented 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 and 50 mL/L acetic acid solutions and vinegar. These treatments were then applied to bead lettuces and browning was measured during 7 days storage at 2 degrees C plus an additional commercialization of 3 days at 13 degrees C. Vinegar and 50 mL/L acetic acid solution inhibited browning on lettuce stem cuttings and could be used to prevent lettuce butt discoloration during cold storage and commercial handling.