Changes in the volatile compounds and physicochemical properties of Wujiuxiang pear fruits during storage

The levels of sugars and organic acids in Wujiuxiang pear (Pyrus communis L. cv. Wujiuxiang) fruit were investigated using high-performance liquid chromatography (HPLC). Volatile compounds from stored Wujiuxiang pear were isolated by solid-phase microextraction (SPME) and analyzed by high-resolution gas chromatography and gas chromatography/mass spectrometry (GC/MS). Fructose was the dominant sugar, followed by glucose and sucrose. With the increase of storage time, fructose levels increased, and at the stage three, the fructose content was the highest. Sucrose and glucose levels decreased unremarkably. The main organic acid was citric acid, followed by malic acid. Citric acid and tartaric acid levels increased during storage. Malic acid and quinic acid increased from stage one to stage two. Shikimic acid level increased from stage one to stage three, then decreased slightly. Acetic acid changed unremarkably. Succinic acid changed not significantly from stage one to stage two, then increased and it was the highest in the stage three. The level in stage four and stage five was lower than the level in stage three. Flesh firmness decreased slightly during storage. Soluble solids content (SSC) increased after three months of storage, then slightly decreased. The dominant aroma components were hexyl acetate (49.35%), butyl acetate (19.56%), ethyl hexanoate (5.16%), ethyl butyrate (4.92%), ethyl acetate (1.08%), and ethyl (E,Z)-2,4-decadienoate (0.84%). Some of the aroma volatile components increased during storage, especially the ester compounds. The results indicated that the quality of Wujiuxiang pear was affected by the changes of volatile compounds and physicochemical properties.