Evaluation of L-Cysteine as Anti-Browning Agent in Fresh-Cut Lettuce Processing

Abstract

Fresh-cut iceberg lettuce was treated with two different concentrations of L-cysteine, in order to select the proper treatment able to improve the storage in air. L-cysteine at 0.1% was selected because it significantly slowed down browning, respiration activity and soluble o-quinones formation and preserved the antioxidant activity. Thus, a second experiment in which this concentration was applied to fresh-cut lettuce processing was carried out. The effectiveness of the treatment with L-cysteine was confirmed and enhanced by the storage in modified atmosphere, increasing the shelf life of 40% respect to control samples. Sensory analysis confirmed the effectiveness of the treatment, showing that fresh-cut lettuce dipped with L-cysteine obtained better scores for appearance, texture, and absence of browning and of unpleasant odor than control. Finally, treatment with L-cysteine resulted with a suitable anti-browning agent, which could be used in fresh-cut lettuce processing. Practical Applications Browning of fresh-cut iceberg lettuce represents one of the major causes of quality loss, which limits its shelf life. This research provides scientific evidence of the use of L-cysteine, as anti-browning agent, in alternative to washing with only hypochlorite in fresh-cut lettuce processing. This treatment could be easily implemented in fresh-cut lettuce processing, as it does not require additional facilities or investment; moreover, it gives advantages to processors and consumers in terms of shelf-life extension and in the improvement of fresh-cut lettuce sensory and quality traits.