Host-guest molecular interactions in vanillin/Hylon VII inclusion complexes

S. D. RODRÍGUEZ; DELIA L. BERNIK

APPLIED SPECTROSCOPY

SOC APPLIED SPECTROSCOPY

Lugar: New York; Año: 2013 vol. 67 p. 884 - 891

0003-7028

The interaction of 4-hydroxy-3-methoxybenzaldehyde (vanillin) and Hylon VII due to the formation of an inclusion complex is studied by Fourier transformed infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and circular dichroism (CD). The results confirm the close interaction among the different functional groups of vanillin and its host.  In addition, a second case study was carried out with an amylose from a different source (100% amylose, APTIII). As a result, remarkable differences were found in the vanillin complexation capability of this amylose, which is only evidenced in solution by circular dichroism spectroscopy studies through a clear Cotton effect. This finding confirm the value of using CD studies, which allow finding that, depending of the amylose source, inclusion complexes can be found only in solution, or both in solution and the coexisting precipitates, when this is evidenced by other techniques such as X-ray diffraction (XRD) or Differential Scanning Calorimetry (DSC). Moreover, solubility assays and complexation of both starches with iodine and subsequent absorption spectroscopy studies gives more information regarding the possible source of the starch encapsulation capability. Thus, Hylon VII evidences higher capacity as vanillin encapsulant than APTIII, showing the formation of inclusion complexes both in solution and solid phase, whereas APTIII complexes are only perceivable in solution.