Discrimination of odors emanating from 'La France' pear by semi-conducting polymer sensors

Odors emanating from 'La France' pears were examined by the electronic odor detection system based on the adsorption on to and subsequent desorption of volatile compounds from an array of semi-conducting polymers, a so-called electronic nose. 'La France' pears were grouped in three storage treatments after being harvested. The first group was the pears stored for 115 days at 277 K, the second and third groups were the pears ripened in a chamber at 303 K for 1 and 5 days, respectively, after the storage of 115 days at 277 K. The physiological states of pears in the three treatments were thought to be different. Pears of the first group were judged to be immature, those of the second group were mature, and those of the third group were over mature. Gas chromatography separation of volatile compounds emanating from 'La France' pear resulted in seven peaks representing acetaldehyde, ethanol, methyl acetate, ethyl acetate, butanol, butyl acetate and hexyl acetate. Odors from pears were detected by the sensor array with 32 different polymers. The odors were classified into three classes dependent on their physiological states through distinctive odor pattern formed by 32 outputs. It was observed that there was the strong relationship between the results obtained by headspace GC and the electronic nose. (C) 2000 Elsevier Science B.V. All rights reserved.