In this master's thesis, we investigated different methods for monitoring the ripeness stage of 'Golden Delicious' apples, with an emphasis on the use of an electronic nose (E-nose) to detect volatile organic compounds released during ripening. The research took place over 26 days and included the measurement of standard ripeness parameters such as color, firmness, weight loss and ethylene production, as well as the comparison of these methods with measurements of volatile organic compounds obtained by electrochemical gas sensors (MQ-3, MQ-135, MQ -136, MQ-138) and ethylene sensor (ME3-C2H4). The results showed that the physical parameters, such as the weight loss and the decrease of color parameter brightness and the increase in the intensity of the yellow color, change according to the maturity stage of apples. Sensor measurements illustrated the expected correlation with standard methods, confirming their accuracy and reliability. Through PCA analysis, we found that the electrochemical sensors proved to be very effective in classifying apples into three different levels of ripeness stages (less ripe, ripe and very ripe), which was confirmed by comparing the color change analysis. The use of an electronic nose offers an easy and fast, and above all, a non-destructive solution for monitoring the maturity of apples, which can significantly contribute to improving storage control and reducing losses taking into account ripeness parameters.
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