Use of the DAindexTM for monitoring fruit ripening evolution in A. chinensis to precisely assess harvesting time “in planta”

BACKGROUND: The assessment of the fruit maturity stage is essential to establish the optimal harvest time and it is considered to be crucial to determine the overall quality and the length of fruit storage-life. In fact the maturity stage reached at harvest is strictly related to the fruit characteristics such as flesh color, taste and aroma resulting in high consumer acceptability. Fruits from the Actinidia chinensis cultivar are traditionally harvested when the flesh color reaches a value of 103◦ Hue equivalent to a bright yellow color (“gold”), recognized as optimal to fulfill the supply chain requirements. This parameter is measured on a fruit sample in the last phase of maturity with a colorimeter, after removing of a thin layer of epicarp. However, since this method implicates the fruit sample destruction, the batch of the considered fruits could be poorly representative. OBJECTIVES: A non-destructive alternative for the assessment of fruit ripening/harvesting was investigated. METHODS: The recently developed Kiwi-meter, a device based on the vis/Near Infrared Spectroscopy (NIRs) allows to monitor fruit flesh color evolution non-destructively by means of the DAindexTM. RESULTS: This work reports the results obtained in different trials in the past years on two A. chinensis cultivars and confirms the importance of the Kiwi-meter device to establish the proper fruit harvest time, fundamental to optimize quality and post-harvest management of kiwifruit, by grouping fruits in homogeneous ripening classes. CONCLUSIONS: The results showed that the Kiwi-Meter could be used “in planta” to monitor the ripening evolution and to assess the harvest time.