Effects of ethylene and 1-MCP on quality maintenance of fresh cut celery

Ethylene is accepted to be a key player in the regulation of climacteric fruit ripening and senescence of leafy vegetables. In contrast, there is still disparity in the literature on the role it may have on quality deterioration of edible petioles. In this work, we evaluated the influence of the ethylene generator 2-chloroethylphosphonic acid (Ethephon) and the ethylene action inhibitor 1-methylcyclopropene (1-MCP) on quality maintenance of fresh cut celery. Commercially mature stalks from self-blanching celery cv. Golden Clause were cut into 2 cm-long slices. Samples from the apical and basal petiole zones were segregated and treated with 2000 mg L-1 2-chloroethylphosphonic acid or with 1 mu L L-1 1-MCP. Corresponding slices without any treatment were used as control. Samples were packed and stored for 0, 6, 13 and 20 d at 4 degrees C and during this period celery visual deterioration (VD), respiration, weight loss and aerobic mesophilic bacteria, yeasts and molds counts were determined. Carotenoids, chlorophylls, phenolics, ascorbic acid, polyphenol oxidase (PPO), sugars, acidity, cell wall content and consumer acceptability were also evaluated. Ethylene had no major effects on weight loss, PPO, phenolic, sugars, acidity, and ascorbic acid. Instead, it increased respiration and accelerated chlorophyll degradation and surface yellowing. These changes were delayed in 1-MCP treated celery, which also maintained lower mesophilic bacteria and yeast counts, showed lower incidence of soft rots. 1-MCP treated celery received higher consumer acceptability scores. The effects were more marked on the samples obtained from the apical region of the petioles. Overall, results reassess the role of ethylene on celery petiole metabolism and indicate that 1-MCP treatments may be useful to supplement the benefits of refrigeration and extend the shelf life of fresh cut self-blanching celery.