C24 and C26 aldehydes are potential natural additives of coating for citrus water retention

•Counted the water loss rate of 75 citrus varieties.•Observed the stomatal state and crystal morphology of 47 citrus varieties.•The water loss rate of fruit was strongly affected by epicuticular wax components.•C24 and C26 aliphatic aldehydes had the greatest impact on fruit water loss rate. Water loss is a key factor for the postharvest senescence of fruit. It has been reported that natural cuticular wax at high concentrations has better performance than commercial coating in water retention of fruit, which can prevent postharvest water loss without the accumulation of off-flavor. Here, we analyzed the correlation between epicuticular wax and postharvest water loss with 75 citrus varieties from a natural population. The water loss rate of the fruit was little influenced by the wax microstructure (stomata and wax crystal morphology), but strongly affected by epicuticular wax components. Further, C24 and C26 aliphatic aldehydes showed the greatest impact on fruit water loss rate, whose correlation coefficients reached –0.63 and –0.67, respectively. These two substances could significantly reduce the fruit water loss rate, indicating that they are potential natural additives to be used in the coating for citrus fruit water retention.