title: Short anaerobiosis period prior to cold storage alleviates bitter pit and superficial scald in Granny Smith apples.
abstract: BACKGROUND
  Californian Granny Smith apples are very susceptible to bitter pit (BP) and superficial scald symptoms that develop during cold storage. The main preventive means are diphenylamine dipping and/or gaseous application of the ethylene inhibitor 1-methylcylclopropene (1-MCP), which is effective against superficial scald but not against BP. This study investigated the efficacy of a non-chemical alternative, low-O(2) (LO2) stress, in preventing these two physiological disorders.
  
  
  RESULTS
  Application of LO2 stress at 20 degrees C for 10 days prior to cold storage of Granny Smith apples reduced superficial scald and BP incidence and severity during 8 months at 0 degrees C. LO2 treatments induced volatile alcohols and reduced ethylene and 6-methyl-5-hepten-2-one (MHO-on) production, thereby reducing superficial scald development after 4 months at 0 degrees C. In addition, LO2-treated fruits had higher pectin methyl esterase (MdPME) gene expression, similar to that of 1-MCP-treated fruits, associated with their higher firmness. Conversion of MHO-on to 6-methyl-5-hepten-2-ol (MHO-ol) in LO2-treated fruits may explain the lower scald development.
  
  
  CONCLUSIONS
  The ratio between MHO-on and MHO-ol might serve as an index of superficial scald severity. Reduction of BP symptoms in LO2-treated fruits could be due to accumulation of volatile alcohols in the peel tissue.
authors.affiliation: Department of Postharvest Science of Fresh Produce, The Volcani Center, PO Box 6, Bet Dagan 50250, Israel. epesis@agri.go.il
authors.forename: Edna
authors.initials: E
authors.lastname: Pesis
authors.forename: Susan E
authors.initials: SE
authors.lastname: Ebeler
authors.forename: Sergio Tonetto
authors.initials: ST
authors.lastname: de Freitas
authors.forename: Malkeet
authors.initials: M
authors.lastname: Padda
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Mitcham
mesh_terms: D000222:Adaptation, Physiological; D000693:Anaerobiosis; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism; D003080:Cold Temperature; D005030:Ethylenes / Q000096:biosynthesis; D005511:Food Handling / Q000379:methods*; D005519:Food Preservation / Q000379:methods*; D005638:Fruit / Q000378:metabolism / Q000592:standards*; D015870:Gene Expression; D007659:Ketones / Q000378:metabolism; D027845:Malus / Q000235:genetics / Q000378:metabolism; D010100:Oxygen / Q000502:physiology*; D013312:Stress, Physiological; D055549:Volatile Organic Compounds / Q000378:metabolism
chemical_list: D005030:Ethylenes; D007659:Ketones; D055549:Volatile Organic Compounds; C029750:methylheptenone; C036216:ethylene; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase; D010100:Oxygen