An insight into the properties of Aegle marmelos pectin-chitosan cross-linked films

Pectin of Aegle marmelos (AP) ripe fruits processed in equal proportion with chitosan (CH) formed films that exhibited minimum swelling index and volume index on exposure to buffers of acidic and alkaline pH. Highest contact angle and spreading coefficient coupled with lowest work of adhesion in all buffers for this film suggested availability of limited number of functional groups for interaction with water molecules due to optimum cross-linking between -NH3+ groups of CH and -COO- groups of AP. This contention was substantiated by the presence of almost negligible charge on this film. The endothermic transition Delta H characteristic of -NH3+-COO- cross-linking between groups in this film was observed to decrease by only 1% after its sequential exposure to pH 1.2 (3 h) and pH 7.4 (6 h). Furthermore, the absence of pores or erosion in the scanning electron photomicrograph suggested the versatility of this film due to its resistance to acidic and alkaline pH. (C) 2012 Elsevier B.V. All rights reserved.