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Significance of Antinutritional
Compounds in Vegetables
Preetilagna Dhal
PhD Scholar,
Department of Vegetable Science, College of Agriculture,
Odisha University of Agriculture & Technology, Bhubaneswar-751003
Corresponding Author
Preetilagna Dhal
Email: preetidhal99@gmail.com
OPEN ACCESS
Keywords
Antinutritional factor, oxalates, saponin, haemagluttin, cynogens
How to cite this article:
Dhal, P. 2020. Significance of antinutritional compounds in vegetables. Vigyan Varta 1(4): 19-21
ABSTRACT
Antinutritional factor is known to interfere with metabolic processes such that growth and
bioavailability of nutrients are negatively influenced. Anti-nutrients are natural compounds
that interfere with the absorption of nutrients, hence are known to reduce nutrients
availability to animals and humans. Vegetables is an important source of protective food and
a part of healthy diet. However, plants generally contain toxic secondary metabolites or anti-
nutritional factors and they have been shown to be highly biologically active. Antinutritional
factor is known to interfere with metabolic processes such that growth and bioavailability of
nutrients are negatively influenced. They include saponins, alkaloids, protease inhibitors,
oxalates, haemaggluttinins (lectin), cyanogens, lethogens, and goitrogen. Some of these plant
chemicals have been shown to be deleterious to health or evidently advantageous to human
health, if consumed in appropriate amounts. However, some antinutrients may exert beneficial
health effects at low concentrations like phytic acid, lectins, tannins, saponins, amylase
inhibitors and protease inhibitors have been shown to reduce the availability of nutrients and
cause growth inhibition. However, when used at low levels, phytate, lectins, tannins, amylase
inhibitors and saponins have also been shown to reduce the blood glucose and insulin
responses to starchy foods and/or the plasma cholesterol and triglycerides. In addition,
phytates, tannins, saponins, protease inhibitors, goitrogens and oxalates have been related to
reduce cancer risks. This implies that anti-nutrients might not always harmful even though lack
of nutritive value.
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INTRODUCTION Cyanogens
nti-nutritional factors are those Cassava and some legumes like kidney bean
substances or chemical compounds contain cyanogenic glycosides from which
Af ound in fruits and food substances in hydrogencyanide (HCN) may be released by
general which are poisonous to humans. They hydrolysis (Akande et al., 2010). The
reduce the ability of nutrients such as minerals, compounds which release HCN on hydrolysis
vitamins and even proteins within the plant are called as “cyanogens”. HCN so released
material. This, in turn, affects the nutritional block the respiration. Their general function in
value of these plants. Anti-nutrients comprise plants is dependent on activation by β-
of amino acids to proteins, simple amines to glucosidases to release toxic volatile HCN as
alkaloids, glycosides and phenolic compounds. well as a ketones or aldehydes to fend off
Anti-nutritional factors are naturally occurring herbivore and pathogen attack.
compounds, present in different vegetables in
varying amounts depending on the kind of food, Oxalate
mode of its propagation, chemicals used in A salt formed from oxalic acid is known as an
growing the crop as well as those chemicals Oxalate: for example, Calcium oxalate, widely
used in storage and preservation of the food distributed in plant kingdom. Strong bonds are
substances (Panhwar, 2005). These anti- formed between oxalic acid, and various other
nutritional factors are also known as “secondary minerals, such as Calcium, Magnesium,
metabolites” in plants and they have been Sodium, and Potassium which, results in the
shown to be highly biologically active. These formation of oxalate salts. Sodium and
secondary metabolites are secondary potassium oxalate salts are soluble, but calcium
compound produced as side products of oxalate salts are basically insoluble. As calcium
processes leading to the synthesis of primary oxalate is insoluble, has the tendency to
metabolites. Antinutrients are chemicals which precipitate (or solidify) in the Kidneys or in the
have been evolved by plants for their own Urinary tract, when the levels are high enough,
defense, they are produced by plants to defend thus forming sharp-edged calcium oxalate
themselves against fungi, insects and predators, crystals. These crystals play a role to the
and offer a protective mechanism for the plant formation of kidney stones in the urinary tract
Tomatine when the acid is excreted in the urine (Nachbar,
2000).
Found in leaves and stem of tomato plants and
- -
has fungicidal, antimicrobial & insecticidal Nitrate (NO3) and Nitrite (NO2)
property. Chemically pure tomatine is a white The high level of these anions is harmful as
crystalline solid at standard temperature and these compounds convert haemoglobin to
pressure, used as reagent, precipitating metaemoglobin (a function less protein) that is
cholesterol act as antidote to mercury. unable to carry out the oxygen transport
Solanine and Chaconine function of the former. The NO3 level more than
75 ppm is toxic while NO2 results in toxicity
Green potatoes have elevated level of solanine beyond 200 ppm. An excessive nitrogen
(30-80% close to skin) which act as defence fertilization can lead to their accumulation in
mechanism to late blight disease and increase vegetables. Both environmental and
level of glycoalkaloid which is bitter in taste. agricultural factors can influence the nitrate
concentrations in vegetables. The former
includes soil moisture, light intensity and
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temperature and the later fertilizers, variety and utilization of nutrients, antinutritive can
crop protection strategies. interfere with food components before intake,
during digestion in the gastrointestinal tract,
Saponins and after absorption in the body but it has some
Saponin found in soybeans, sugar beets, positive effects like promoting the growth of
peanuts, spinach, asparagus, broccoli, potatoes, beneficial bacteria. The lectins present in
eggplants (Price et al., 1987). Saponin is bitter legumes assessed to act as a mucosal adjuvant,
in taste and can haemolyse red blood cells. It beneficial outcome in hypercholesterolemia
occurs in all parts of plant, although the after intake of heat-treated chickpea in rats have
concentration is affected by variety and stage of been observed.
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