Microscopic Detection of Adulteration of Bengal Gram (Cicer Arietinum) Flour with other Legume Flour based on the Seed Testa Macrosclereids

Besan, the flour of Bengal gram (Cicer arietinum
Linn), a legume, is a popular ingredient of many culinary
dishes in India. Because of its high demand, its flour is
often adulterated by that of other legumes, such as,
Lathyrus sativus (lathyrus) or Pisum sativum (pea) by
unscrupulous traders. There are chemical methods of paper
chromatography and HPLC by which the adulteration with
the flour of L. sativus can be established but they are
sophisticated techniques. At present, there are no chemical
methods by which the adulteration with the flour of P.
sativum can be detected. Microscopy is a simple technique
and has been used for detection of adulteration of a number
of food grains. Microscopic observation of the flour of
these three legumes showed that their seed testa macrosclereids
are distinct in their shape and size. The macrosclereids
of C. arietinum are longer with a mean length of
155.6 microns and are bent at one end. Those of either P.
sativum or L. sativus are shorter with a mean length of 61.8
and 72 microns respectively, with flat ends and with a
different morphology. The seed testa macrosclereids of
other edible legumes also show differences in morphology.
Thus, it was observed that microscopic observation of the
besan flour for the macrosclereids of other legumes is a
powerful but simple means by which detection of adulteration
of besan with the flour of P. sativum or L. sativus or
by other edible legumes can be made. These observations
make the subject matter of this manuscript.