The fruit is contained in a spiny (very sharp) cupule 5–11 cm in diameter, also called "bur" or "burr". The burrs are often paired or clustered on the branch (source: wikipedia)
Chestnuts depart from the norm for culinary nuts in that they have very little protein or fat, their calories coming chiefly from carbohydrates. Fresh chestnut fruits have about 180 calories (800 kJ) per 100 grams of edible parts, which is much lower than walnuts, almonds, other nuts and dried fruit (about 600 kcal/100 g). Chestnuts contain very little fat, mostly unsaturated, and no gluten.(source : wikipedia)
To preserve their freshness for a few months with no artificial refrigeration, the chestnuts can be soaked in cold water for about 20 hours immediately after harvest, after which they are dried in the shade, then layered in dry sand(source:wikipedia)
In Korea, jujubes are called daechu (대추) and are used in Daechucha teas and samgyetang.