Monitoring Postharvest Ethylene Emissions in Fresh Produce: Potential of Metal Oxide Semiconductor-Based Gas Sensors

Ethylene is a key plant hormone that regulates the ripening and senescence of fresh produce. Although it is essential for maturation, its presence also accelerates deterioration, leading to quality loss and food waste. Real-time ethylene monitoring is crucial for optimizing postharvest management and extending shelf life in storage and distribution networks. Among the various gas sensing technologies, metal oxide semiconductor (MOS)-based sensors have emerged as a promising solution owing to their high response, simple structure, and cost-effectiveness. However, detecting ethylene in complex postharvest environments remains challenging because of its low reactivity and cross-sensitivity to interfering gases. This review explores advancements in modern ethylene sensor technologies, with a particular focus on MOS-based ethylene sensors. Key strategies for enhancing sensor response and selectivity are examined, including nanostructuring, catalyst decoration, composite material development, and bilayer film fabrication. Additionally, the integration of sensor arrays and machine learning techniques for precise real-time ethylene detection is discussed. By addressing existing challenges and recent innovations, this review provides valuable insights into MOS-based ethylene sensing and offers guidance for the development of next-generation sensors. These advancements hold significant potential for improving postharvest management, reducing food waste, and enhancing supply chain efficiency in fresh produce distribution networks.