Nfluence Of Ethylene On The Quality Of Peach Fruit And Its Physiological Mechanism During MA Storage

Peach is one of the widely planted fruit trees in the world. Consumers like peach fruit because of its delicious flavor. The storage and transportation of peach fruit at ambient temperature is challenging because of the easy soft and decay. Low temperature can prolong the storage time, but is associated with several side-effects including severe symptoms of chilling injury and altered characteristic flavor, which result in reduced commercial value. At present, researchers pay more attention to persevering the flavor characteristics of peach fruit during the low temperature storage.This study investigated the influence of exogenous ethylene of different concentrations on the major flavor compounds and activities of relative enzyme of'Okubao'(Amygdalus persica L.) and'Bayuecui'(Amygdalus persica L.) peach fruit during MA(Modified Atmosphere,0～1℃) storage as well as 3 days shelf-life at 20℃using the techniques of HS-SPME; the influence of exogenous ethylene on the relative physiological indices of peach fruit and interaction between exogenous ethylene and endogenous ethylene were also conducted. The results were as following:1. The exogenous ethylene compensation increased the adaptability of the peach fruit during the early stage of the storage. Peach fruit had an improved ability to copy with the chilling injury after 3 days shelf life of the middle stage of the storage. Although the ethylene inhibitor treatment delayed the peach fruit consenescence during the low temperature storage and had a lowest rot exponent after 3 days shelf life, it reduced the low temperature adaptability at the early stage of the storage. After 24 days storage, the peach fruit exhibited harder firmness earlier than untreated controls and showed irreversible hardness.2. Ethylene compensated treatment increased the ethylene released peak value and respiration rate peak value at the early stage of the storage. The ethylene inhibitor—1-MCP treatment, delayed the respiration peak value and reduced the ethylene peak value.3. Ethylene had different effects on several enzymes inside the peach fruit. Our research indicated that exogenous ethylene treatment reduced the peach fruit PPO activity and LOX activity. So it lightened the fruit browning. 1-MCP treatment had dual effects on the fruit, it reduced the LOX activity during the storage stage in favor of delaying the consenescence. It stimulated the LOX activity after 3days shelf life and increased the degree of chilling injury.4. Ethylene inhibitor counteracted the increase of PE activity at the early stage of the storage and delayed the soluble pectin making fastigium. PG activity was not obviously affected. The ethylene compensation treatment increased the pectin disassembling and accelerated the membrane metabolic activity, which make the fruit oral ripen at the early stage of the storage.5. Ethylene restraining or compensation had no evident effects on the benzaldehyde content; both 1-MCP treatment and ethylene absorbor treatment inhibit the production of the hexanal and trans-2-hexanal. The ethylene compensation significantly accelerated the production of trans-2-hexanal while had no evident effect on the hexanal. The ethylene inhibitor increased the linalool content and reduced theγ-decalactone content indicating that ethylene counteracted function on the front content and accelerated function on the behind content. This research indicated that ethylene inhibition or elimination altered the normal mature of peach fruit and some mechanisms of chilling injury.In summary, the exogenous ethylene treatment results in the physiological and biochemic changes in peach fruit. So it can affect the peach fruit quality. Ethylene treatment affected the peach fruit during the MA early and middle storage. Considering the comprehensive effects of different ethylene concentrations on the main quality factors of peach fruit, we concluded that the treatment with (5～10)μl·L-1 exogenous ethylene had the best effect.