title: Ester variability in apple varieties as determined by solid-phase microextraction and gas chromatography-mass spectrometry.
abstract: Solid-phase microextraction (SPME) with a polydimethylsiloxane fiber coupled with gas chromatography-mass spectrometry (GC-MS) was applied to the study of variability in volatiles released by 13 apple varieties. The relative amounts of 40 esters and alpha-farnesene were determined. Principal component analyses of these results clustered the apples into three groups according to skin color: red, green, and red-green. Total ester contents were highest with the red cluster apples, and the green cluster apples had the highest alpha-farnesene levels. This technology was also applied to the monitoring of changes in volatiles for apples removed from controlled-atmosphere storage with subsequent storage at 4 degrees C and room temperature. Total ester contents increased 25-fold, with the greater increases coming at room temperature, whereas alpha-farnesene levels increased only 5-fold. For apples stored at room temperature, after 11 days, the amount of increase was inversely proportional to the size of the ester: levels of smallest esters (molecular weight 116) increased 12.5-fold, and the largest esters (molecular weight 228) increased approximately 1.3-fold.
authors.affiliation: Food and Research Program, Agriculture and Agri-Food Canada, 93 Stone Road West, Guelph, Ontario, N1G 5C9, Canada. youngjc@agr.gc.ca
authors.forename: J Christopher
authors.initials: JC
authors.lastname: Young
authors.forename: C L George
authors.initials: CL
authors.lastname: Chu
authors.forename: Xuewen
authors.initials: X
authors.lastname: Lu
authors.forename: Honghui
authors.initials: H
authors.lastname: Zhu
mesh_terms: D004952:Esters / Q000032:analysis*; D005519:Food Preservation; D005638:Fruit / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D027845:Malus / Q000737:chemistry* / Q000145:classification; D010858:Pigmentation; D012717:Sesquiterpenes / Q000032:analysis; D013045:Species Specificity; D013696:Temperature; D013997:Time Factors
chemical_list: D004952:Esters; D012717:Sesquiterpenes; C062672:alpha-farnesene