Red Delicious和Granny Smith苹果在田间成熟及不同气调贮藏结合1-MCP处理下挥发性有机化合物谱的比较

亮点
    研究了‘Red Delicious’和‘Granny Smith’在田间成熟过程中的挥发性有机化合物（VOC）特征。
    品种特异性和贮藏特异性香气谱揭示了VOC的不同动态变化。
    超低氧（ULO）和基于叶绿素荧光的动态控制大气（DCA-CF）结合1-甲基环丙烯（1-MCP）处理可保持果实品质，但抑制了VOC的产生。
    在采后贮藏中需平衡整体品质与香气。


Abstract
Apples (Malus × domestica Borkh.) are stored up to one year, however, postharvest technologies designed to preserve texture, taste and to extend storage life may alter aroma by affecting volatile organic compound (VOC) biosynthesis. This study investigated VOC dynamics in two commercially important cultivars with contrasting ripening physiology, ‘Red Delicious’ and ‘Granny Smith’. VOC profiles were characterized during field ripening to establish cultivar-specific references. Subsequently, the effects of storage atmospheres (regular air, RA; ultra-low oxygen, ULO; and dynamic controlled atmosphere based on chlorophyll fluorescence, DCA-CF), with or without 1-methylcyclopropene (1-MCP), and an additional 8-week shelf-life period in RA were evaluated. During field ripening, ‘Red Delicious’ showed a climacteric pattern, shifting from aldehyde- to ester-dominated profiles, whereas ‘Granny Smith’ maintained low ethylene production and an aldehyde-driven profile. Across storage treatments, 1-MCP had the strongest effect, markedly suppressing VOC production, particularly esters in ‘Red Delicious’ and alcohols in ‘Granny Smith’, especially under DCA-CF. RA promoted higher VOC accumulation, while ULO and DCA-CF limited VOC production. Post-storage recovery partially restored alcohols and ester biosynthesis in ‘Red Delicious’, with negligible effects in ‘Granny Smith’. Multivariate analysis indicated that RA + 1-MCP, ULO and DCA-CF preserved aroma similarity to field reference in ‘Red Delicious’, whereas only ULO and DCA-CF, when combined with 1-MCP, preserved aroma similarity in ‘Granny Smith’. VOC discrimination was driven by esters in ‘Red Delicious’ and by aldehydes and alcohols in ‘Granny Smith’. These results highlight cultivar-specific trade-offs between storage conditions and aroma, supporting the use of field-reference VOC profiles as benchmarks for optimizing postharvest strategies.

摘要
苹果（Malus × domestica Borkh.）可贮藏长达一年，然而，旨在保持质地、风味并延长贮藏寿命的采后技术可能通过影响挥发性有机化合物（VOC）的生物合成而改变香气。本研究调查了两种具有不同成熟生理特性的商业重要品种——‘Red Delicious’和‘Granny Smith’苹果——的VOC动态。首先，在田间成熟期间对VOC谱进行了表征，以建立品种特异性参考。随后，评估了不同贮藏气调（普通空气，RA；超低氧，ULO；以及基于叶绿素荧光的动态控制大气，DCA-CF）结合或不结合1-MCP处理，以及额外8周普通空气货架期的影响。在田间成熟过程中，‘Red Delicious’表现出跃变型模式，VOC谱从以醛类为主转变为以酯类为主，而‘Granny Smith’则保持较低的乙烯产量和以醛类为主的谱型。在所有贮藏处理中，1-MCP的影响最显著，显著抑制了VOC的产生，尤其是在DCA-CF下，‘Red Delicious’的酯类产生和‘Granny Smith’的醇类产生受到明显抑制。普通空气贮藏促进了较高的VOC积累，而ULO和DCA-CF则限制了VOC的产生。采后货架期部分恢复了‘Red Delicious’中醇类和酯类的生物合成，而对‘Granny Smith’影响甚微。多变量分析表明，对于‘Red Delicious’，RA+1-MCP、ULO和DCA-CF处理保持了与田间参考相似的香气特征，而对于‘Granny Smith’，只有ULO和DCA-CF结合1-MCP处理保持了香气相似性。VOC的区分在‘Red Delicious’中主要由酯类驱动，而在‘Granny Smith’中主要由醛类和醇类驱动。这些结果突显了贮藏条件与香气之间品种特异性的权衡关系，并支持将田间参考VOC谱作为优化采后策略的基准。


Keywords：Malus domestica; Ripening; Target VOC analysis; Aroma; Dynamic controlled atmosphere; 1-MCP; Odor activity value

关键词： 苹果；成熟；目标VOC分析；香气；动态控制大气；1-MCP；气味活性值


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2. Materials and methods
2.2. Ripening monitoring and field reference definition
Starting on 22 August for ‘Red Delicious’ and 1 September for ‘Granny Smith’, fruits were sampled weekly during field ripening (Supp. Tab. 1). At each sampling, 30 fruits were collected from both the sun-exposed and shaded sides of the canopy at mid-canopy height from 10 representative trees per cultivar and analyzed with the semi-automated ‘Pimprenelle’ system (Setop Giraud Technology, France) which measures soluble solids content (°Brix), flesh firmness (N), and titratable acidity (g L⁻¹, expressed as malic acid (MA) equivalents). Measurements were performed on subsamples of 10 fruits (Zanella and Werth, 2004). These measurements were used to assess physiological ripening and reduce variability associated with fruit ripening differences; results are reported in the Supplementary Table 1. Fruit samples were additionally prepared for VOC profile analysis as described in Section 2.7. The “field reference” used for VOC profile comparison before and after storage was defined as the profile of fruit beyond the climacteric peak of ethylene production, as described in Section 3.1. This reference served as a physiological benchmark for evaluating postharvest-induced changes in VOC profiles.
2. 材料与方法
2.2. 成熟监测与田间参考定义
自8月22日（‘Red Delicious’）和9月1日（‘Granny Smith’）起，在田间成熟期间每周采集果实样品（见补充表1）。每次采样时，从每个品种的10棵代表性树的树冠中部高度处，分别从阳面和阴面各采集30个果实，并使用半自动“Pimprenelle”系统（Setop Giraud Technology, France）进行分析，测定可溶性固形物含量（°Brix）、果肉硬度（N）和可滴定酸度（g L⁻¹，以苹果酸当量计）。测量在10个果实的子样本上进行（Zanella和Werth，2004）。这些测量用于评估生理成熟度，并减少与果实成熟差异相关的变异性；结果见补充表1。果实样品还按第2.7节所述制备用于VOC谱分析。用于贮藏前后VOC谱比较的“田间参考”定义为果实超过乙烯跃变峰后的谱型，详见第3.1节。该参考作为评价采后处理引起的VOC谱变化的生理基准。