Postharvest chilling injury (PCI) is a significant limitation in the storage of temperature-sensitive fruits, leading to quality deterioration and reduced marketability. However, low temperatures delay senescence—consistent with the Q10 principle, where metabolic reaction rates change 2–3-fold per 10 °C—and chilling-sensitive fruits experience membrane destabilization, oxidative imbalances, and structural degradation under cold stress. Physiological assessments consistently report elevated electrolyte leakage, increased malondialdehyde accumulation, and reduced membrane fluidity, coupled with disruptions in respiration and cellular energy metabolism. Biochemically, PCI is characterized by enhanced ROS production and a 20–50% decline in key antioxidant enzymes, along with disturbances in calcium signaling and hormone regulation. At the molecular level, chilling-responsive transcription factors such as CBF, CAM, HSF, and WRKY show strong induction, while lipid remodeling and epigenetic modifications further shape cold adaptation responses. Advances in multi-omics, including transcriptomics, proteomics, metabolomics, lipidomics, and volatilomics, have revealed chilling-associated metabolic shifts and regulatory cascades, enabling the identification of potential biomarkers of tolerance. Emerging mitigation strategies, including physical and chemical treatments, as well as CRISPR-based interventions, have shown a 30–60% reduction in PCI in controlled studies. This review synthesizes recent progress in physiology, molecular biochemistry, and postharvest technology to support future research and practical PCI management.

The storage of fruit at minimum oxygen condition is crucial for optimal fruit quality maintenance. However, the optimal oxygen partial pressure of fruit varies according to several factors such as species, cultivar, harvest maturity, temperature, growing season and storage period. Based on these factors, storage technologies were developed that allow for the detection of the lower oxygen limit (LOL) and the storage of fruit under the lowest optimal oxygen partial pressure. One emerging technology is known as dynamic controlled atmosphere (DCA). Commercially, there are four DCA systems used: [1] DCA based on ethanol production and accumulation (DCA-Eth); [2] DCA based on chlorophyll fluorescence (DCA-CF); DCA based on the respiratory quotient (DCA-RQ) and [4] DCA based solely on CO2 production (DCA-CD). This reviews the recent developments of these DCA systems and their effect on fruit quality. Generally, the storage of fruit under DCA has a positive effect on the overall fruit quality, with regards to reduced physiological disorders and higher flesh firmness maintenance, when compared to controlled atmosphere (CA). Evidence also shows that storing fruit under DCA-RQ and DCA-CD allowed higher volatile compound emission and concentration, which can contribute positively to fruit flavor. The DCA systems are “green storage technologies” because the system enables the increase of storage temperature and thereby saving electrical energy. Storage of apples under DCA maintains an overall fruit quality similar to CA combined with the ripening inhibitor 1-Methylcyclopropen (1-MCP), which is an interesting option for organic fruit storage. Dynamic controlled atmosphere is a recently developed storage technique and is in constant improvement. The latest developed DCA techniques (DCA-RQ and DCA-CD), in contrast to DCA-CF, allow the use of extremely low oxygen levels. In the future, new and multi-sensor DCA systems are under development, which might not just control O2 partial pressure but also temperature and other parameters to allow for more energy efficient but high quality fruit storage systems.

Apples are stored at temperatures close to 0 °C and high relative humidity (up to 95%) under controlled atmosphere conditions. Under these conditions, the cyclic operation of the refrigeration machine and the associated temperature fluctuations can lead to localized undershoots of the dew point on fruit surfaces. The primary question for the present study was to prove that such condensation processes can be measured under practical conditions during apple storage. Using the example of a measuring point in the upper apple layer of a large bin in the supply air area, this evidence was provided. Using two independent measuring methods, a wetness sensor attached to the apple surface and determination of climatic conditions near the fruit, the phases of condensation, namely active condensation and evaporation, were measured over three weeks as a function of the operating time of the cooling system components (refrigeration machine, fans, defrosting regime). The system for measurement and continuous data acquisition in the case of an airtight CA-storage room is presented and the influence of the operation of the cooling system components in relation to condensation phenomena was evaluated. Depending on the set point specifications for ventilation and defrost control, condensed water was present on the apple surface between 33.4% and 100% of the duration of the varying cooling/re-warming cycles.