Physiological Studies On Aroma Volatile Formation In Peach Fruit

Peach is one of the widely planted temperate-zone tree fruit in the world, and it an important position in Chinese fruit production, the area and yield at first place in the world. Melting peach cultivar is know for its excellent flavor and juiciness, and grown worldwide in southern China. With the improvement of life in recent years, people take more care of fruit quality. Especially, aroma was much accounted by planters, consumers and breeders. It has been one of the essential factors for evaluating peach fruit quality. This study, using two melting peach varieties, 'Hujingmilu' (Prunus persica L.) and 'Yulu' (Prunus persica L.) were therefore designed to test three subjects: (1)Changes in formation of aroma compounds during fruit development; (2)The influence of 1-MCP treatments on synthesis of ethylene and aroma in peaches at postharvest; (3)Changes in free fatty acid and several enzyme activities in LOX during peach fruit maturation. Results were as following:(1) Seven major aroma compounds were detected in two peach varieties, such as so-called "green aroma" trans-2-hexenal and cis-3-hexenol, and so-called "fruity aroma" γ-hexelactone, γ-octalactone, γ-decalactone, 5-decalactone, and γ-dodecalactone. The formation of characteristic aroma compounds of peach is a dynamic process during maturation, so the characteristic aroma composition changes both qualitatively and quantitatively. The composition was similar in two varieties, but the concentration of aroma was different. Trans-2-hexenal and cis-3-hexenol are the major compounds in immature fruit. The concentration of C6 compounds decreased, whereas those of γ-hexelactone, γ-octalactone, γ-decalactone, 5-decalactone, and γ-dodecalactone increased significantly as fruit maturation and reaching the highest in mature fruit. The formation of "fruity aroma" largely after commence of ethylene climactic, moreover, aroma concentration and ethylene production reach maximum at the same time. It is suggested that ethylene release take important role in regulation of aroma formation. In addition, with ethylene and respiration rate climactic, flesh firmness decreased, ground color from green to yellow, TSS increased, TA decreased during maturation.(2) Effect of 1-MCP on the ethylene production and aroma formation in melting "Hujingmilu" was tested. Application of 1-MCP was at 20℃ for 12 h and at concentrations were 1ppm, 5ppm, and 50ppm. Air treatment was as control (CK). The...