**4. Discussion**

Acorn squash has characteristic inedible, hard, thin skin, and firm flesh. The flesh is very sweet with a nut-like flavor after baking, microwaving, sautéing, or steaming. This squash is an excellent source of nutrients, including carotenoids, ascorbic acid, and vitamin C [7]. It is best known as a source of carotenoids—primarily b-carotene—and lutein, which are beneficial, respectively, as a provitamin A compound and for general health [8]. Market opportunities for growers have extended into the fall/winter season and Acorn squash occupies an important late-season niche in Israel, therefore it is anticipated that this market has scope for increased growth in Israel and elsewhere [9].

To the best of our knowledge, there is very little published information about the optimal temperature for prolonged storage of Acorn squash. Acorn squash is considered a winter squash that can be stored at 10–12 ◦C for 2–3 months, while lower temperatures cause chilling injuries, and those above 20 ◦C increase weight loss and decay incidence [10]. In the present study 15 ◦C was found the best temperature to keep the fruit for 3.5 months. However, to keep the fruit at 15 ◦C for several months without affecting its quality, it is necessary to use HWRB treatment, whose beneficial effects on fresh-harvested produce were reported by Fallik [5,6]. HWRB treatments can remove fungal pathogens from the fruit surface through the brushing effect, and the natural wax platelets could be melted and smoothed to seal stomatal openings or invisible surface cracks, thereby reducing decay development and water loss and, in turn, increase fruit firmness (Tables 1 and 2) [5]. The lower decay incidence in HWRB-treated Acorn squash could also be attributed to the induction of pathogenesis-related proteins and the accumulation of enzymes such as chitinase and β-1,3-glucanase, which hydrolyze the fungal cell walls and inactivate the pathogens [5]. This treatment also was reported to delay fruit ripening, which may partially account for the delayed color development of the HWRB-treated fruits (Tables 1 and 2; Figure 1).

In conclusion, a prestorage HWRB treatment at 52 ◦C for about 15 s, followed by storage at 15 ◦C can maintain Acorn squash quality and marketability for several months. However, more research is needed to extend Acorn squash storability beyond 3.5 months, by evaluating new varieties and other prestorage treatments such as plant-growth regulators that delay chlorophyll degradation during prolonged storage, or by using edible coating materials.

**Author Contributions:** D.C., S.A.-T. and M.Z.-P. are research engineers in Elazar Fallik's laboratory; they conducted the experiments, evaluated fruit quality, and analyzed the data in both 2016 and 2017. E.F. planned the research, harvested the fruits, analyzed the results and wrote the manuscript.

**Funding:** This paper is Contribution No. 825.18 from the Agricultural Research Organization, the Volcani Center, Rishon LeZiyyon, Israel.

**Conflicts of Interest:** The authors declare no conflict of interest.
