New post-harvest aproach for high quality fresh ‘Medjhool’ date

•Evaluation of post-harvest treatments to produce “super fresh” ‘Medjhool’ dates.•Non-destructive NIR measuring system was established for sorting the Khalal dates.•38-40 Brix% was found as minimum TSS for production of “super fresh” ‘Medjhool’.•The best postharvest treatment was the heating followed by freezing and defrosting.

In Israel, ‘Medjhool’ has become the major date fruit variety. In a certain ripeness stage they become super succulent, juicy, tasty (“Super Fresh” ‘Medjhool’) and have a high market value compared to regular ‘Medjhool’ dates. At this particular stage, the dates are very difficult to handle (picking up, removing etc.). Harvesting of ‘Medjhool’ dates after having matured but before ripening (Khalal ‘Medjhool’) followed by suitable postharvest treatment to enforce ripening, might provide farmers a method to produce a high quality product. At this pre-ripe stage, dates' total soluble solid (TSS) content varies considerably. The objectives of this study were to find an appropriate post-harvest treatment to produce “Super Fresh” ‘Medjhool’ dates from the Khalal fruits and to develop a method for online sorting of Khalal ‘Medjhool’ dates according to their TSS content using a mini NIR spectrometer. A cells' conveyor, an automatic sorting apparatus and a NIR (850–1880 nm) scanning device were designed and constructed, simulating a real sorting operation. Spectral models for TSS prediction were developed, based on Partial Least Squares regression. The root mean square prediction error of TSS was in the range of 0.9–1.6% in the different prediction models. This study establishes the basis for sorting dates for consequent postharvest treatment, using NIR spectroscopy, in the production process of “Super Fresh” ‘Medjhool’ dates.