Effects of carbon monoxide on quality, nutrients and antioxidant activity of post‐harvest jujube

Abstract

To effectively extend the shelf life of fresh jujube, carbon monoxide (CO), as a small molecular gas, was applied to fumigate fresh jujube. The quality and antioxidant activity of jujubes fumigated with carbon monoxide at concentrations of 0 (control), 5, 10, 20 and 40 µmol L⁻¹ for 1 h under ambient temperature were investigated. The jujube fumigated with 10 µmol L⁻¹ CO showed the best preserving effect amongst all samples. At 30 days, the decay incidence of jujube fumigated with 10 µmol L⁻¹ CO is only two-thirds of that of control sample; its red index and weight loss rate were 22.8% and 19.4% lower, and its firmness, soluble solids content (SSC) and acidity were 18.7%, 5.4% and 12.2% higher than that of control samples, respectively. Its vitamin C and total flavonoid contents were also the highest. However, no significant difference in total polyphenol content was found. The jujubes treated with 10 µmol L⁻¹ CO exhibited the highest antioxidant activity in terms of reducing power and 2,2-diphenyl-1-(2,4,6-trinitrophenyl)hydrazyl radical scavenging activity. However, the jujubes fumigated with 40 µmol L⁻¹ CO showed inferior characteristics compared with the control sample. Fumigating jujubes with proper concentration of CO probably is a potential novel method for post-harvest jujube preservation in the future.