a sweet substance appearing at certain seasons on a wide range of plants, from trees to grasses. Manna is associated with infestation by scale insects, but it is often unclear whether the manna is exuded by the plant as the result of insect wounds or is, like honeydew, a secretion of the insects themselves. Because of the multiplicity of sources, the identity of a given manna is often debatable. Donkin (1980), in a book-length monograph on the subject, has made the greatest single contribution to such debates.
Three mannas have importance as food. The best known is tamarisk manna, a white, honey-like substance which appears on the desert tree Tamarix mannifera when infested by insects such as Coccus manniparus. This manna is known in Arabic as mann, in Persian as taranjabin (literally, ‘fresh honey’, because unlike bees' honey it is not enclosed in a comb but drips off the plant in hot weather), and as gezo (from gez, tamarisk) among the Kurds of N. Iraq, in whose region it is commercially gathered.
By the time tamarisk manna enters commerce it is a grey, sticky mass, about 10% of which is glucose and fructose, the remainder being sucrose and several other non-reducing sugars plus inedible residue. It is traditionally prepared by boiling in water and clarifying with eggs. The resulting syrup is most often made into a sort of halva (in Kurdish, helwa-y-gezo) with more eggs and perhaps the addition of almonds.
The second important manna appears on two spiny-branched shrubs known as camel's-thorn, Alhagi maurorum and A. pseudalhagi. It dries readily and is harvested by shaking the branches of the shrub over cloth. The highly descriptive Persian name is tabashir taranjabin (chalk manna). Camel's-thorn manna is primarily sucrose.
The third important manna is not produced by insects. It is a light or dark brown lichen, Lecanora esculenta, which can be dislodged from rocks by high winds and blown through the desert, sometimes raining on human settlements. Syrian Bedouins, whose name for it means ‘earth fat’, mix two parts of it with one part meal and make bread. A sort of jelly is also made. The Turkish word for lichen manna is tıgala, which provides the scientific name for the sugar present in it, trehalose.
Most other mannas are primarily of medicinal importance. Such is ash manna, produced by the flowering ash, Fraxinus ornus, which is the source of the laxative mannitol, although also used as a sweet confection.
The manna which is referred to as man in the 16th chapter of Exodus is a miraculous food, intended not only to sustain the Hebrews during their wanderings in Sinai, but to teach faith and obedience. Moses commanded the people not to gather more than they needed for one day, and those who doubted that Providence would send manna again on the morrow, and therefore gathered more than they needed, found that the excess rotted and bred worms. Conversely, a double portion was sent on Fridays so that it could be baked or boiled for consumption the next day without violating the Sabbath. This ‘bread of Heaven’ cannot be safely identified with any known vegetable manna.
Charles Perry, the leading authority on early Arab cookery, has recently published A Baghdad Cookery Book Newly Translated (2005) and a related 13
Donkin, R. A. (1980), Manna: An Historical Geography, The Hague: Dr W. Junk.
