Comparative FTIR Characterization of Various Natural Gums: A Criterion for Their Identification

Proper identification and differentiation of natural polysaccharides is a very crucial task owing to some similarities in their appearance and properties. This research presents an extensive use of FTIR, a well-established and authenticated tool, for identifying and differentiating different classes of gums. Commercially important natural gums including plant exudate gums, seed gums, seaweed gums, microbial gums and animal gums were chosen for the study. For plant exudate gums, a peak at 1424 cm − 1 is common to all, which is absent in other classes of gums. A shoulder peak at 1728 cm − 1 and an ester group vibration peak at 1075 cm − 1 make gum karaya different from other gums. Peaks at 1647 cm − 1 and 1384 cm − 1 , common to all seed gums, are absent in other gums and help to set identifying criteria for seed gums. In microbial gums, xanthan and gellan have no peaks in the range of 755–775 cm − 1 , unlike other gums. In the case of animal gums (chitosan and gelatin) an intense sharp peak at 1636 cm − 1 is attributed to CONH 2 group. Similarly, the paper explains characteristic peaks for gellan, carrageenan, agar, sodium alginate and other gums. Along with the in-depth discussion of major gum’s FTIR, this paper also endorses FTIR as a potential technique for identifying and differentiating natural gums.