TOXIC CONSTITUENTS
Some pulses contain chemical constitucnts having toxic properties.
Trypsin inhibitors
They are present in red gram, Bengal gram, cowpea, double beans, soyabean, lathyrus sativus and
peas. Trypsin inhibitors are proteins that inhibit the activity of trypsin in the gut and interfere with
digestibility of dietary proteins and reduce their utilisation. Pancreas enlargement and growth retardation
0ccur in animals that consume diet containing trypsin inhibitors. The release of essential amino acids.
particularly, methionine is hampered by the presence of inhibitors. They are generally heat labile and
moist heat treatment like pressure cooking destroys them. Autoclaving at 120°C for 15-30 minutes
inactivates almost all trypsin inhibitors. Trypsin inhibitors are easily inactivated from dals but more
drastic heat treatment is necessary to inactivate trypsin inhibitors of soyabean and kidney bean. These
inhibitors prevent degradation of storage proteins during seed maturation.
Lathyrogens
Lathyrism is a nervous disease that cripples man. This is entirely preventable. The disease now
known to result from an excessive consumption of the pulse Lathyrus sativus. It affects young men
between the age of 15 to 45 years.
Lathyrus sativus is grown in dry districts of Madhya Pradesh, Uttar Pradesh, Bihar, West Bengal,
Maharashtra, Mysore and Andhra Pradesh. Throughout the country, it is known by the common
name "Khesari Dal". The dehusked seeds resemble Bengal gram dal or red gram dhal. Hence, some
times kesari dhal is used as an adulterant in other dals. If the rains fail and there is poor crop of
wheat, a useful harvest of lathyrus may be reaped. When it is eaten in small quantities lathyrus seeds
are valuable as food since it contains 28 per cent protein. But if they are the main source of energy
providing more than 50 per cent a severe disease of spinal cord may result.
The symptoms of lathyrism are muscular rigidity, weakness, paralysis of the leg muscle.
Stages of Lathyrism
First stage: It is characterised by a typical manner of walking with short steps and jerky movements
and akind of scissors or crossed gait. This is non-stick stage. The patient may remain in this condition
for the rest of his life, or he may pass on to the next stage.
Second stage: The muscular stiffness is increased and this makes it necessary to perform all
walking by tilting the pelvis to such a degree that a stick is necessary to maintain balance. This is
called one-stick stage.
Third stage: The muscular rigidity is so great that the patient needs two sticks for support and
there is marked tilting of the pelvis sideways to maintain balance. This is called two-stick stage.
Final stage: By this time, the patient is unable to walk upright on account of considerable
bending of the knees and extreme stiffness of the lower limbs. The patient is then reduced to crawling
by taking his weight on his hands.
Some pulses contain chemical constitucnts having toxic properties.
Trypsin inhibitors
They are present in red gram, Bengal gram, cowpea, double beans, soyabean, lathyrus sativus and
peas. Trypsin inhibitors are proteins that inhibit the activity of trypsin in the gut and interfere with
digestibility of dietary proteins and reduce their utilisation. Pancreas enlargement and growth retardation
0ccur in animals that consume diet containing trypsin inhibitors. The release of essential amino acids.
particularly, methionine is hampered by the presence of inhibitors. They are generally heat labile and
moist heat treatment like pressure cooking destroys them. Autoclaving at 120°C for 15-30 minutes
inactivates almost all trypsin inhibitors. Trypsin inhibitors are easily inactivated from dals but more
drastic heat treatment is necessary to inactivate trypsin inhibitors of soyabean and kidney bean. These
inhibitors prevent degradation of storage proteins during seed maturation.
Lathyrogens
Lathyrism is a nervous disease that cripples man. This is entirely preventable. The disease now
known to result from an excessive consumption of the pulse Lathyrus sativus. It affects young men
between the age of 15 to 45 years.
Lathyrus sativus is grown in dry districts of Madhya Pradesh, Uttar Pradesh, Bihar, West Bengal,
Maharashtra, Mysore and Andhra Pradesh. Throughout the country, it is known by the common
name "Khesari Dal". The dehusked seeds resemble Bengal gram dal or red gram dhal. Hence, some
times kesari dhal is used as an adulterant in other dals. If the rains fail and there is poor crop of
wheat, a useful harvest of lathyrus may be reaped. When it is eaten in small quantities lathyrus seeds
are valuable as food since it contains 28 per cent protein. But if they are the main source of energy
providing more than 50 per cent a severe disease of spinal cord may result.
The symptoms of lathyrism are muscular rigidity, weakness, paralysis of the leg muscle.
Stages of Lathyrism
First stage: It is characterised by a typical manner of walking with short steps and jerky movements
and akind of scissors or crossed gait. This is non-stick stage. The patient may remain in this condition
for the rest of his life, or he may pass on to the next stage.
Second stage: The muscular stiffness is increased and this makes it necessary to perform all
walking by tilting the pelvis to such a degree that a stick is necessary to maintain balance. This is
called one-stick stage.
Third stage: The muscular rigidity is so great that the patient needs two sticks for support and
there is marked tilting of the pelvis sideways to maintain balance. This is called two-stick stage.
Final stage: By this time, the patient is unable to walk upright on account of considerable
bending of the knees and extreme stiffness of the lower limbs. The patient is then reduced to crawling
by taking his weight on his hands.
