Fruit ripening evolution in diverse commercial apricots by conventional and non-destructive methods: preliminary results

Cultivated apricot (Prunus armeniaca L.) is represented by a growing number of commercial cultivars featuring a wide variability of flesh texture and ripening evolution, affecting the entire chain from harvest to the final consumer. In order to establish fast and reliable tools easy applicable in the field to determine the harvest time, diverse commercial apricots were evaluated over 2 years for fruit ripening evolution by conventional and non-destructive methods. All fruit were harvested from a single tree at physiological ripening onset, then fruit were graded with a DA-meter® device, according to three ripening stages (physiological and commercial ripening, veraison), 30 fruit each. Fruit from each stage, after being scored by a near-infrared analyzer, were than randomly divided into three batches, each of which was subjected to standard ripening assessment: firmness (Fi) by using a digital penetrometer, soluble solids content (SSC) by using a digital refractometer, and total acidity (TA) by titration and pH measurement. Fi and SSC were assessed on both fruit sides, while TA and pH were determined on 10 homogenized fruits. The curves produced after optimization showed good predictability, particularly for TA, SSC and pH: R2 was 78.57, 79.17 and 80.56 (in cross-validation, respectively), despite the diversity of the assessed cultivars and the different stages of ripening. Some more work still has to be done to improve the predictability of Fi (R2=38.53), and further investigation has to be carried out to better fit the data from the penetrometer, or other devices measuring flesh texture. These results are to be considered as preliminary for the setting up of cultivar-specific harvest parameters.