Quality monitoring of table grapes stored in controlled atmosphere using an S3+MOS nanosensor device

This study explores the use and the effectiveness of advanced sensor technology to monitor and maintain the quality of table grapes, cv. Italia, stored at 2 °C in controlled atmospheres (CA) over different storage times. Two CA conditions were evaluated: CA-1 with suitable conditions (3 % O₂, 10 % CO₂) and CA-2 harsh conditions (3 % O₂, 30 % CO₂), in comparison to conventional air storage. Using the Metal Oxide Gas sensors (S3 + electronic nose) and the classical approach of Solid Phase Microextraction-Gas Chromatography-Mass Spectrometry (SPME-GC-MS) to validate sensor data, the research analyzed the grapes' volatilome, identifying total volatile organic compounds (VOCs) and markers of freshness and quality degradation. Results indicate that gaseous mixtures significantly influence the volatile composition of grapes, affecting sensory attributes and shelf life. While both CA treatments improved visual quality by reducing oxidation, browning, and mould development, they also increased respiration rates, leading to the production of volatiles that negatively impacted aroma over time. The S3 + electronic nose findings are closely aligned with GC-MS results, demonstrating that grapes stored in CA-2 deviated significantly from both fresh samples and those stored in CA-1 or conventional air. CA-2, with its higher CO₂ concentration, was the least favorable for maintaining grape quality. The study highlights the potential of S3 + IoT nanosensors for real-time VOC monitoring, providing an effective tool for agri-food quality management. Integrating S3 + sensors into storage systems could optimize conditions, minimize waste, and enhance supply chain efficiency and sustainability.