CUCUMBER SEEDS (TOḴM-E ḴIĀR)

Cucumis sativus Linnaeus (Family Cucurbitaceae), commonly known as cucumber, bears fruit with mucilage inside those aids in attaching the seeds to the pulp. Initially cultivated in Southern Asia, it now thrives on most continents, flourishing in both tropical and temperate regions. The term for cucumber (Cucumis sativus L.) in various languages, including Persian, is "khiār," as mentioned by Biruni (440 A.H./1048 A.D). The characteristics of cucumber and its cultivation are also discussed by Shahmardan b. Abi’l-Kheir al-Razi in Nozhat name-ye ‘ala’i (490-495 A.H./1097-1102 A.D.).

Recipes
Regarding paper sizing, historical recipes mention cucumber seed mucilage, most likely referring to the extract of the mucilage inside the fruit, which aids in attaching the seeds to the pith. Both Golzār-e Ṣafā and Ḵaṭṭ va Morakkab both written in 16th century briefly mention it as another paper sizing material. In Golzār-e Ṣafā (950 A.H./1543 A.D.), Ali Seyrafi notes cucumber-seed mucilage as the third suitable material out of six ingredients for sizing, following mucilage of psyllium and preceding grape syrup:

سومین تخم خیار است ضرور

The third is cucumber seed, of value

Hossein Aqili Rostamdari says the following in his book Ḵaṭṭ va Morakkab (978 A.H./1571 A.D.):

طریقی دیگر آن که تخم خیار را در آب ریزند تا لعاب باز دهد و بعد از آن کاغذ در آن اندازند و بیرون آورند

Another method is to place cucumber seeds in water until their mucilage is extracted. Afterwards, place the paper in [the mixture] and remove it.

It is to be noted that the term toḵm-e ḵiār may also refer to the seeds of melon family since It is reported that in different parts of Iran provinces such as in Kermān and Bahābād the term ḵiār when it is used alone is referred to a melon known ḵarboze and the general term for cucumber is called ḵiār-e sabz or ḵiār bālang meaning green cucumber. Jamāli-ye Yazdi in his book Farrokhnameh has used the term ḵiār for melon (ḵarboze).

In Jowhar-e Simi and Resāle dar Bayān-e Kāḡaḏ Morakkab va Ḥall-e Alvān, the authors state āb-e tohkm-e ḵiārein[1] as one of the sizing materials. The word āb, usually refers to juice or extract, is probably used to mean mucilage in this case since it refers to the seeds of the fruit. (See the recipe of Mixed Sizes).

[1] Steingass: a خیارین  ḵẖiyārain (dual), The two kinds of cucumber, i.e. the cucumber and the musk-melon  (cucumis melo); their seeds (used medicinally).