title: High-temperature conditioning induces chilling tolerance in mandarin fruit: a cell wall approach.
abstract: BACKGROUND
  High-temperature conditioning (3 days at 37 °C and 95% relative humidity), which protects 'Fortune' mandarins from chilling injury (CI), manifested as pitting in the outer part of the peel (flavedo), was applied prior to cold storage (2 °C) in order to investigate the involvement of cell wall composition in the chilling tolerance of mandarins.
  
  
  RESULTS
  Both low-temperature storage and high-temperature conditioning barely modified the alcohol-insoluble substance (AIS) content or the degree of pectin esterification in the flavedo. Water-soluble pectins (WSP) were higher in heat-conditioned than in non-conditioned fruits at the onset of CI. In addition, the heat-conditioning treatment was able to increase chelator-soluble pectins (CSP) after short cold storage periods. Covalently bound polyuronides in alkali-soluble pectins (ASP) increased only in fruits with high incidence of CI. Cellulose and hemicellulose increased at 2 °C in both conditioned and non-conditioned fruits, indicating that these polysaccharides may be altered by low temperature but are not related to chilling-induced damage.
  
  
  CONCLUSIONS
  High-temperature conditioning may reduce chilling-induced flavedo pitting in 'Fortune' mandarin fruit by maintaining normal levels of WSP and increasing putative sites for calcium bridge formation within the cell wall, but not by inducing changes in other matrix cell wall components.
authors.affiliation: Instituto de Agroquímica y Tecnología de Alimentos, CSIC, Burjassot, Valencia, Spain.
authors.forename: Nély
authors.initials: N
authors.lastname: Holland
authors.forename: Francisca L da Silva
authors.initials: FL
authors.lastname: Nunes
authors.forename: Igor U Dantas
authors.initials: IU
authors.lastname: de Medeiros
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Lafuente
mesh_terms: D002473:Cell Wall / Q000737:chemistry*; D002482:Cellulose / Q000032:analysis; D002957:Citrus; D003080:Cold Temperature / Q000009:adverse effects*; D004951:Esterification; D005030:Ethylenes / Q000096:biosynthesis; D005519:Food Preservation / Q000379:methods*; D061353:Food Storage; D005638:Fruit / Q000378:metabolism / Q000648:ultrastructure*; D006358:Hot Temperature; D006813:Humidity; D010368:Pectins / Q000032:analysis / Q000737:chemistry; D012995:Solubility; D014574:Uronic Acids / Q000032:analysis
chemical_list: D005030:Ethylenes; D014574:Uronic Acids; C018402:traumacel; D010368:Pectins; D002482:Cellulose; C036216:ethylene