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 APPLICATIONSBrowning 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.

Suitability for Ready-to-Eat Processing and Preservation of Six Green and Red Baby Leaves Cultivars and Evaluation of Their Antioxidant Value during Storage and after the Expiration Date

“…These last values are lower than those reported for fresh‐cut iceberg lettuce (about 20–40 mL CO 2 /kg/h) (Deza‐Durand and Petersen ; Pace et al . ), confirming the good suitability of these cultivars to be processed as RTE product (Kader ).…”

“…), whereas in whole iceberg lettuces no changes in phenol content were observed over storage (Pace et al . ).…”

Effect of basil leaves and wheat bran water extracts on enzymatic browning of shredded storage iceberg lettuce

“…This phenomenon is reflected in an increase in the value of the browning index (Mi et al ., ). Previously, enzymatic browning was effectively inhibited by phenolic‐rich extracts (Sukhonthara & Theerakulkait, ; Wessels et al ., ; Sukhonthara et al ., ; Romani et al ., ) as well as thiol‐containing compounds such as cysteine (Pérez‐Balibrea et al ., ; Arogundade & Mu, ; Pace et al ., ); hence, extracts that were rich in these components were studied in the screening. According to literature data, wheat bran is an excellent source of ferulic acid (Prückler et al ., ).…”

“…Pace et al . () reported the highest value of the browning index after 6 days of storage of fresh‐cut iceberg lettuce. Also, Chen et al .…”

Mild heat treatment inhibits the browning of fresh-cut Agaricus bisporus during cold storage

“…Various approaches have been used to control browning of fresh-cut fruits and vegetables, e.g. chemical antioxidants (Barbagallo, Chisari, & Caputa, 2012;Pace, Capotorto, Ventura, & Cefola, 2015;Zhou, Li, Wu, Fan, & Ouyang, 2015), edible coating (Sharma & Rao, 2015), essential oil treatment (Chen et al, 2017;Kim, Kim, Chung, & Moon, 2014), UV treatment (Lante, Tinello, & Nicoletto, 2016) and combination of them (Koushesh Saba & Sogvar, 2016). However, some of these strategies could have drawbacks, including potentially toxicity, high cost, low stability and impairing the organoleptic and nutritional properties of the produce.…”