Submitted to: Postharvest Biology and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/19/2008
Publication Date: 2/2/2009
Citation: Jin, P., Zheng, Y., Tang, S., Rui, H., Wang, C.Y. 2009. A combination of hot air and methyl jasmonate vapor treatment alleviates chilling injury of peach fruit. Postharvest Biology and Technology. 52:24-29. Interpretive Summary: Peaches are difficult to handle after harvest. They ripen rapidly at high temperatures and become soft and mealy. On the other hand, they are susceptible to chilling injury and internal breakdown if kept at cold temperatures. We found that by using a combined treatment of hot air and methyl jasmonate, peach quality could be maintained with less chilling injury symptoms at 0 degree centigrade. In addition, peaches exposed to this combined treatment retain more extractable juice with less flesh mealiness and higher sugars and acids than non treated fruit. Therefore, the combination of hot air and methyl jasmonate treatment could be a useful technique in alleviating chilling injury and maintaining quality of peach fruit during cold storage. The results of this research could be useful to the peach industry and consumers.
Technical Abstract: Peaches were harvested at firm-mature stage and treated with various combinations of methyl jasmonate (MeJA) and hot air. Severity of internal browning and flesh mealiness, firmness, extractable juice rate, total soluble solids (TSS), total acid, vitamin C and total phenolic contents were measured after 3 and 5 weeks of storage at 0 °C plus 3 d at 20 °C for shelf-life. The activities of phenylalanine ammonia-lyase, superoxide dismutase, polyphenol oxidase, peroxidase, pectin- methylesterase and polygalacturonase were analyzed every 7 d during the cold storage period. The results showed that fruits treated with 1 µmolL-1 MJ vapor at 38 °C for 12 h (HMJ), and heat treatment at 38 °C for 12 h and then treated with 1 µmolL-1 MJ vapor at 20 °C for 24 h (HA+MJ) had the highest quality and lowest percent of chilling injury symptoms. Hot air treatment alone significantly inhibited internal browning, but caused more severe flesh mealiness than other treatments, but this side effect was counteracted by MJ. The percent of extractable juice rate in combined treatments was higher than that in the control, however, no significant effect was found on firmness. TSS was 23 % and 25.3 % higher and total acid was 59.4 % and 62.5 % higher in treatments of HMJ and HA+MJ respectively, than that in control fruit after storage for 5 weeks. Vitamin C and total phenolic contents were also maintained at higher levels in combined treatments. In addition, the combined treatments resulted in higher activities in PAL, SOD and PG, and lower activities in PPO and POD than the control. The combination of hot air and MJ vapor treatment could be a useful technique to alleviate chilling injury and maintain peach fruit quality during cold storage.