Pulses
Introduction
Pulses are plants of the family Leguminosae which are collected and eaten mostly for their dry seeds. Such seeds have a big size (> 2 mm diametre), and are characterised by their high protein and carbohydrate content, which makes them a crucial source of food in most civilisations. Most species are annual.
Pulse species share many characteristics and many uses. This similarity allows a species to substitute another easily in gardens and cooking, making particularly difficult the identification of species out of popular names.
Many species are also grown for their fresh seeds (petit pois), their fresh pods, their roots or tubers, their leaves or shoots, or even their flowers. They are then considered as vegetables.
Soybean (Glycine max) is a pulse in China, but it is also an oil plant. Peanut (Arachis hypogaea) is considered as well as an oil plant or as a nut. Fenugreek (Trigonella foenum-graecum) has particular properties. As for vetches (Vicia), they are usually excluded from pulses, and included in forages.
Uses
In Europe, only pea is used in the forme of dry broken peas (pois cassés). In contrast, in India, more than 75% of pulse production is used after hulling seeds and separating the two cotyledons. This type of preparation is called dāl, whatever species is involved, be it lentil, urd, mung, cajan pea or chickpea. Dal can be eaten entire after cooking, in a soup or mashed into a purée. It is also pounded into a flour and grilled as flat cakes. India is by far the region in the world where consumption of pulses is highest, as a consequence of taboo on beef meat consumption in Hindu religion, or even on any meat for an important part of population. In the Near-East, some pulses are also eaten broken, as red lentil in Syria and Irak, or faba bean in Egypt.
Many pulses are known to provoque flatulences. The cause is their content in sugars such as raffinose and stachyose, which are not digested, but ferment in the big intestine, producing several gases (carbonic gas, hydrogen and methane). Entire seeds can be eaten when they begin to sprout, which enhances their taste; this is a frequent practice in eastern Asia. In India, they are often grilled after sprouting, a process also applied to cereals under the name of malting. Mung and pea are mostly used in that way, as well as soybean, cajan pea, faba bean and chickpea. At a later stage of sprouting, when plantlets or shoots reach several centimeters long, they can be eaten as a fresh vegetable, raw or cooked. The species mostly used by far as sprouts is mung, but soybean and pea can also be founde, as well as alfalfa (which is not considered here as a pulse).
Botany
All pulses belong to the family Leguminosae (Fabaceae), and more especially sub-family Papilionoideae (Faboideae). Species are classified in seven botanical tribes, two major ones being Phaseoleae and Vicieae.
- tribe Phaseoleae
- sub-tribe Cajaninae
- sub-tribe Diocleinae
- sub-tribe Glycininae
- sub-tribe Phaseolinae
- tribe Vicieae
- tribe Cicereae
- tribe Aeschynomeneae
- tribe Genisteae
- tribe Indigofereae
- tribe Trifolieae
Some authors consider as pulses some species of Caesalpinioideae (Cordeauxia, Tylosema) or Mimosoideae, which are often trees, but when seeds are eaten, have the same properties as other pulses.
