From http://www.avesta.org/mp/grb12.htm:
- The principal fruits are of thirty species; ten species of them are fit to be eaten inside and outside, such as the fig, the apple, the quince, the cucumber, the grape, the mulberry, [the cluster of dates,] the pears and others of this species; [and other] ten are fit to be eaten outside, and are not fit to be eaten inside, such as the date, the peach, the small apricot of white [breast, the lote fruit, the myrobalan, the 'sar' and others of this species]; those [ten] which are fit to be eaten inside, and are not fit to be eaten outside, are [such as] the walnut, the almond, the pomegranate, the cocoanut, the hazel nuts the chestnut, the tree of Georgia [which they also name the pistachio nut, and] those, too, which [are] more than these, but [these] several [are] the principal ones; [those which they plant with two splits and two stems, such as the 'veh khurmar', the myrobalan, the 'awam', and others of this species they call the grafts.]
I thought you used "inside" and "outside" to mean "indoors" and "outdoors" but from reading the passage it seems clear that it refers to the inside and outside of the fruit: you can eat both the inside and outside of a cucumber, only the inside of a walnut (the outside is a shell) and only the outside of a peach (the inside is the stone).