Optimization of controlled atmosphere (CA) storage of pome fruit crucially depends on understanding of respiratory gas exchange. Different fruit properties are involved in describing gas transfer and respiration kinetics, which can vary between cultivars, fruit batches and individual fruit. Determination of these properties currently requires a combination of different time-consuming techniques and data analysis procedures. This study introduces a more efficient single method for O gas exchange characterization of fruit based on the non-destructive pathlength-resolved GASMAS (gas in scattering media absorption spectroscopy) technique. GASMAS was used to measure the absolute intercellular O concentration in fruit of different apple cultivars ( x Borkh.) with distinct porosity including 'Jonagold', 'Braeburn', and 'Nicoter'. To resolve the ambiguity between variation in pathlength and O concentration inherent to GASMAS, the pathlength travelled through pores cavities was quantified through a second GASMAS measurement at the absorption line of HO vapour. Dynamic experiments were then performed in which the fruit was subjected to varying external O concentrations while measuring the internal O response. The observed dynamic profiles of external and internal O concentration were fitted with a lumped -respiration model to estimate the effective mass transfer coefficient, maximum respiration rate and Michaelis Menten constant of intact fruit. The model showed a good fit (>0.95) with the measured data and reliable estimates for the model parameters. The proposed method provides a novel and more efficient way to estimate the gas exchange properties of fruit that are essential for optimizing CA storage conditions. Future challenges for the proposed method are with applications to other gasses such as CO and ethylene.

中文翻译：

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使用光程分辨 GASMAS 有效估计苹果的气体交换和呼吸动力学

仁果气调 (CA) 储存的优化关键取决于对呼吸气体交换的了解。描述气体转移和呼吸动力学涉及不同的水果特性，这些特性在品种、水果批次和单个水果之间可能有所不同。目前，确定这些属性需要结合不同的耗时技术和数据分析程序。本研究介绍了一种基于无损光程分辨 GASMAS（散射介质中气体吸收光谱）技术的水果 O 气体交换表征的更有效的单一方法。 GASMAS 用于测量具有不同孔隙度的不同苹果品种 (x Borkh.) 果实中的绝对细胞间 O 浓度，包括“Jonagold”、“Braeburn”和“Nicoter”。为了解决 GASMAS 固有的光程变化和 O 浓度变化之间的模糊性，通过 H2O 蒸气吸收线处的第二次 GASMAS 测量来量化穿过孔腔的光程长度。然后进行动态实验，其中水果受到不同的外部 O 浓度的影响，同时测量内部 O 响应。观察到的外部和内部氧气浓度的动态曲线与集总呼吸模型相拟合，以估计完整果实的有效传质系数、最大呼吸速率和米氏常数。该模型显示出与测量数据的良好拟合（>0.95）以及模型参数的可靠估计。该方法提供了一种新颖且更有效的方法来估计水果的气体交换特性，这对于优化 CA 储存条件至关重要。所提出的方法未来的挑战是应用于其他气体，如二氧化碳和乙烯。