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.