Aroma composition in relation with quality of 'Peento' flat peach during fruit development. (Special Issue: Tunisian fruit and vegetables.)

摘要

'Peento' flat peach (Prunus persica L.), increasingly encountered in Tunisian agrosystems, is characterized by tasty and flavoured fruit with a marked and specific aroma that develops when ripe. Volatile compounds of 'Peento' peaches were separated using liquid-liquid extraction with pentane and di-ethyl ether and analysed by gas chromatography/flame ionisation detection (GC/FID). Peach samples produced an average of 3674 micro g aroma/g fresh weight (FW) at full ripeness. Lactones was the major class of volatiles described with delta -dodecalactone as the main compound (18.4%) followed by delta -undecalactone (15.3%). Other constituents, including ketones (2), esters (1), alcohols (1), monoterpenes (1) and sesquiterpenes (1), were also identified. 'Elegant Lady' fruits, gathered during the same period, produced 2072 micro g aroma/g FW. Methyl isovalerate (13.0%) and delta -undecalactone (7.9%) were the major compounds identified. delta -Dodecalactone was less abundant in the fruit aroma (3.3%) compared to flat peaches. Changes in volatile composition showed a significant increase until maturity. Besides, volatile concentrations decreased. Lactones, the greatest contributors to the peachy note, continued to rise independently of total volatiles produced. The quality of 'Peento' flat peach is influenced by its aroma composition, in particular to the level of lactones in the parenchyma. The date of harvest seemed to be of great importance in preserving fruit quality attributes. Physiological maturity is considered to be the optimal time for harvest. Anticipated as well delayed harvest could result in a dramatic loss of scent and aroma developed by the fruit. The emission of volatile compounds appears to be a useful index for determining the physiological maturity of 'Peento' peaches in an orchard prior to harvest.