Present Production and Utilization of Khesari
Production
Khesari covers about 30% of the area and production of all pulses in Bangladesh. There is a gradual decline in both hectarage and production of this crop (Islam and Rahman 1990). This decline is associated with the overall reduction in the total hectarage and production of all pulses. It is one of the major sources of protein in the diet of the poor people of Bangladesh where 59% of the households suffer from protein deficiency. It is also the cheapest of all pulses although its present price is likely to go beyond the reach of the common people soon. It is a tasty food. It may contain up to 3 5 % protein and has a good amount of lysine, which improves the usual rice-based diet. Khesari, therefore, provides a nourishing diet of good-quality protein and carbohydrate (350 cal 100-1 g). According to Misra (1978), khesari may be deficient in methionine but not in tryptophan like other pulses. Hence its protein is of good quality.
The utilization Khesari is often a common ingredient of the menu of the daily diet of the people of Bangladesh, especially the poor. Most often khesari seeds are eaten as dhal which is an aqueous slurry cooked with spices. It is also eaten as a cooked paste mixed with vegetables or occasionally with dry fish in some regions of Bangladesh along wit h the major meal. Khesari is consumed quite often in the form of chapati (unleavened bread) or dhalpuri containing varying proportions of wheat and khesari and also as bora prepared in the form of deepfried paste balls. Often this bora contains different proportions of lentil (Lens culinaris Medic.) and khesari seed powder. In addition, khesari is also consumed by boiling the mature pods and as roasted seed with roasted rice. Khichuri, a Bengali dish, is prepared by cooking rice with variable proportions of khesari seed. This is a really nutritious meal in terms of quality and quantity of protein. Sometimes whole or crushed khesari seeds are boiled in water and eaten as porridge. The young khesari plant is a very nutritious and tasty leafy vegetable eaten with rice meal. During the lean period, especially in the northern region of Bangladesh, poor people live on khesari. It is known to be a survival food item during the famine. Often the farm laborers are given their daily wage in the form of khesari seed, a factor that seems to contribute to the incidence of lathyrism.
Khesari makes an excellent fodder crop. Lactating cows grazing on young khesari plants are often believed to yield more milk. After harvest, the plants are dried and stored for future use as feed. Khesari grain and bran are known to be fattening feed concentrates.
Khesari and Lathyrism
Lathyrism
Lathyrism is a neurologic disease which results from excessive consumption of khesari seed. This disease is characterized by muscular rigidity, weakness, and paralysis of the leg muscles. The onset of the disease is often sudden. A laborer while trying to resume his work after a rest at the end of hard work for a couple of hours or after a night's sleep, suddenly stumbles and falls. He complains of pain in the back. His lower limbs become stiff. A physician may term this disability as spastic paralysis of lower limbs. Reports of lathyrism were found in many countries including some in Europe and Africa. It has been eradicated in European countries by a ban on khesari cultivation. But it is still a crippling disease in India and Bangladesh. Legislative measures to ban khesari in India failed to discourage farmers from growing it. There are now about 10000 patients of lathyrism in Bangladesh (Kaul and Islam 1982).
Several factors are believed to cause lathyrism. These include phytates, alkaloids, lack of vitamins A , B and C, and virus infection (Sarma and Padmanabhan 1969). High selenium and low methionine in the lathyrus seeds were considered to cause lathyrism. Also the seeds of Vicia species present as contaminants of market samples of khesari seeds were claimed to cause toxicity. The main problem in identifying the toxic factor was the lack of a suitable experimental animal which responds to the toxic factor in khesari seed. Roy et al. (1963) devised an assay procedure using khesari extract on 1-day old chicks when symptoms similar to human lathyrism appeared. This assay procedure led to the identification in khesari of the toxic factor ß-N-oxalyl-L ß-diaminopropionic acid (ODAP), otherwise designated as ß-N-oxalyl aminoalanine (BOA A ).
Vitamin C and lathyrism Ahmad and Jahan (1983) reported that adult guinea pigs and monkeys when fed on cooked khesari supplemented with all vitamins except vitamin C became paralyzed in 3-7 weeks while those on the same diet supplemented daily with 5 mg of vitamin C remained healthy. When khesari was replaced by any other legume or cereal in a vitamin A-deficient diet neurolathyrism symptoms or neurolathyrism did not appear. They claimed to have cured fresh cases of human lathyrism by intravenous administration of 500 to 1000 mg of ascorbic acid daily. Reports corroborating these findings are yet to be published. These findings, however, lend support to the view that incidence of lathyrism is closely linked to the deficiency of nutrients (Islam 1983).
Quantities and Procedures for Safe Consumption
It has been found that harmful effects of neurolathyrism are produced in 2-4 months with a diet of which 4 0 % or more is made up of khesari seeds. In order to avoid its toxic effects, khesari should never form more than one-fourth of the total amount of cereals and pulses eaten each day. Ahmad and Jahan (1982) opined that a population well-nourished in respect of vitamin C will not develop neurolathyrism in spite of the use of khesari as a principal item in the diet. A number of procedures were suggested to eliminate the toxins from khesari for safe consumption. Mohan et al. (1966) suggested the removal of the toxin by, (a) steeping dehusked seed in hot water for several hours, (b) boiling the seed in water and draining the supernatant, and (c) parboiling. These methods of detoxification would remove several of the useful water-soluble nutrients, reduce the weight (of pulse grain), and affect taste and glutinous property required for the preparation of dough for chapatis. Roy et al. (1963) recommended the roasting of seeds. However, it adversely affects the chapati-making property. Ahmad and Jahan (1982) reported that khesari is not fully detoxicated if it is treated with hot water to wash out the toxin which is, nevertheless, a water-soluble substance. They found that residues of washing caused lathyritic symptoms in animals suggesting that either a considerable amount of it exists in bound form not removed by hot water or there are other toxins that are not soluble in water. Thus a variety of khesari having less O D A P may not necessarily be nontoxic