Abstract The effect of long-term storage of ‘Conference’ pears under ultra-low oxygen levels with or without multiple oxygen pull downs of different duration on fruit quality, ethylene emission, fermentative metabolites and volatile organic compounds (VOCs) was investigated. Pears were cold stored for seven months under three different atmospheres: initial low oxygen stress (ILOS), dynamic low oxygen pull downs monitored with a chlorophyll fluorescence sensor (DLOS1) and extended dynamic or repeated low oxygen pull downs (DLOS2). Overall, the application of repeated oxygen pull downs in the atmosphere composition (DLOS1 and DLOS2) did not affect the fruit firmness upon removal from cold storage. Our results showed that fruit submitted to multiple oxygen pull downs (DLOS1 and DLOS2) ripened slower when further placed at 20 °C, as indicated by changes in the index of absorbance difference (IAD), the fruit ethylene production capacity and the accumulation of ethanol within the fruit pulp. Moreover, the detected concentrations of specific VOCs (butyl acetate, hexyl propanoate and α-farnesene) inside the storage atmosphere correlated well with some ripening parameters (IAD), thereby suggesting that specific VOCs could be used as fruit ripening state markers for real-time monitoring throughout the storage of ‘Conference’ pears.

中文翻译：

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长期冷藏期间“会议”梨重复氧气下降的 VOC 排放和质量演变

摘要 研究了在超低氧水平下长期储存“会议”梨，有或没有不同持续时间的多次氧气下拉对果实质量、乙烯排放、发酵代谢物和挥发性有机化合物 (VOCs) 的影响。梨在三种不同的气氛下冷藏七个月：初始低氧压力 (ILOS)、用叶绿素荧光传感器监测的动态低氧下拉 (DLOS1) 和延长的动态或重复低氧下拉 (DLOS2)。总体而言，在大气成分（DLOS1 和 DLOS2）中重复应用氧气下拉不会影响水果从冷藏中取出后的硬度。我们的结果表明，在 20 °C 下进一步放置时，经受多次氧气下拉（DLOS1 和 DLOS2）的水果成熟得更慢，如吸光度差指数（IAD）、水果乙烯生产能力和果肉内乙醇积累的变化所示。此外，在储存气氛中检测到的特定 VOCs（乙酸丁酯、丙酸己酯和α-法呢烯）的浓度与一些成熟参数（IAD）有很好的相关性，从而表明特定 VOCs 可以用作水果成熟状态的实时标记。在整个“会议”梨的存储过程中进行监控。