title: Effects of carbon monoxide on quality, nutrients and antioxidant activity of post-harvest jujube.
abstract: BACKGROUND
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  Fumigating jujubes with proper concentration of CO probably is a potential novel method for post-harvest jujube preservation in the future.
authors.affiliation: College of Engineering, Shanxi Normal University, Linfen City, Shanxi, 041004, China.
authors.forename: Shaoying
authors.initials: S
authors.lastname: Zhang
authors.forename: Na
authors.initials: N
authors.lastname: Li
mesh_terms: D000963:Antimetabolites / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D000975:Antioxidants / Q000032:analysis* / Q000737:chemistry; D001205:Ascorbic Acid / Q000032:analysis; D002248:Carbon Monoxide / Q000737:chemistry / Q000494:pharmacology* / Q000633:toxicity; D055598:Chemical Phenomena; D002681:China; D005419:Flavonoids / Q000032:analysis; D005519:Food Preservation; D063427:Food Quality; D061353:Food Storage; D005638:Fruit / Q000737:chemistry / Q000187:drug effects*; D005651:Fumigation / Q000009:adverse effects; D006801:Humans; D006863:Hydrogen-Ion Concentration; D055595:Mechanical Phenomena; D009753:Nutritive Value; D010858:Pigmentation / Q000187:drug effects; D012995:Solubility; D031957:Ziziphus / Q000737:chemistry / Q000187:drug effects*
chemical_list: D000963:Antimetabolites; D000975:Antioxidants; D005419:Flavonoids; D002248:Carbon Monoxide; D001205:Ascorbic Acid
keywords: antioxidant activity; carbon monoxide; jujube; nutrients; quality