Study On Effects Of Lower Pressure, 1-MCP And CO₂ Treatments On Peach Fruits

"QING ZHOU MI TAO"peach (Prunus Persica (L) Batsch.), nectrarina (P. Persica Var.nectarina Maxim) and "PAN TAO"peach (P. Persica Var. compressa Bean.) fruits had been studied in this paper during 2001 and 2002. Lower pressure treatment was used as a main way to research the characteristics of peach fruits and to improve the ability of storage of peach fruits when stored in coldroom (0 0.5 C). The experiment was divided into three parts as following:(l) lower pressure treatment; (2) lower pressure+1-MCP treatment; (3) lower pressure +CO2 CA treament (2%~3%02+4%CO2). In this experiment the second and the third items treated and "PAN TAO" peach "QING ZHOU MI TAO" peach during 2002. Nectrarina was only treated by lower pressure during 2003.The results showed that "QING ZHOU MI TAO"peach is better than nectraina, which is better than "PAN TAO"peach in its ability of storage. "QING ZHOU MI TAO"peach, nectranrina and "PAN TAO " peach as climacertic fruits all have obviously two peaks of respiration rate during storage. Lower pressure and lower pressure+1-MCP treaments delayed the two peaks of respiration rate of "QING ZHOU MI TAO"peach and nectranria and could only delay (7days) the second peak of respiration of "PAN TAO" peach. Lower pressure+CO2 CA treatment delayed the two peaks of respiration of peach fruits of "QING ZHOU MI TAO and "PAN TAO "peaches. All treatments restrained dramatically the values of the second peak of respiration rate of fruits of three cultivars. At the end of storage (lOOdays for "QING ZHOU MI TAO" peach, 50days for "PAN TAO"peach and 50 days for nectraina), fruits of the three peach cultivars remained their original corlours. SOD and CAT activities of fruits treated by lower pressure+1-MCP were relative higher than those of controlled fruits and lower pressure+1-MCP treatment surpressed PPO activity largely. Though fruits of all treatments lost flavors in some degree during storage, the fruits treated by lower pressure+1-MCP and lower pressure treatments were better than controlled fruits. Fruits that were treated by lower pressure+CO2 CA had been moldy and those that weren't treated by lower pressure+CO2 remained well. This indicated that the content of CO2 (4%)used in the experiment had injured fruits, which is called carbon dioxide injure. Thus we need to manipulate the content of CO2 to a suitable degree.In short, this experiment showed that lower pressure and lowerpressure+1-MCP treatments are expected to be good approaches to improve the ability of storage of the peach fruits. If only we can identify the most suitable content of CO2, lower pressure+CO2 CA treatments is also a good way to prolong the storage time of peach. The fruter experiment should be focused on following items:(1) Identifing the most suitable content of CO2 in the treatment of lower pressure + CO2 CA.(2) How to protect the flavors of peach fruits.(3) How to prevent the fruits from browning.(4) Identifying the most suitable time for the fruits to enter into the market.