Entrapment of ethyl vanillin in calcium alginate and calcium alginate/poly(vinyl alcohol) beads

Electrostatic extrusion was applied to the encapsulation of 3-ethoxy-4-hydroxybenzaldehyde (ethyl vanillin) in calcium alginate and calcium alginate/poly(vinyl alcohol) beads. The calcium alginate/poly(vinyl alcohol) hydrogel spheres were formed after contact with the cross-linker solution of calcium chloride, followed by the freeze-thaw method for poly(vinyl alcohol) gel formation. The entrapment of aroma in beads was investigated by FTIR and thermal analysis (thermogravimetry/differential thermal gravimetry; TGA/DTG). The mass loss in the temperature range of 150-300A degrees C is related to degradation of the matrix and the release of ethyl vanillin. According to the DTG curve, the release of ethyl vanillin occurs at about 260A degrees C. TGA measurements of the stored samples confirmed that formulations were stable for a period of one month. FTIR analysis provides no evidence for chemical interactions between flavour and alginate that would alter the nature of the functional groups in the flavour compound. (C) 2012 Institute of Chemistry, Slovak Academy of Sciences