Distribution and competition between carvacrol and propylene glycol for trapping by amylose in aqueous suspensions based on potato starch and konjac glucomannan
Résumé
The quantification and the distribution of carvacrol and propylene glycol between the continuous phase and the dispersed phase of aqueous suspensions based on potato starch and konjac glucomannan were investigated. For this purpose, a series of potato starch suspensions with or without konjac glucomannan were prepared by hydrothermal treatment. Two different modes of adding ligands were used: either added before the heating of the suspensions or after the heating of the suspensions. X-ray diffraction and differential scanning calorimetry studies confirmed the presence of carvacrol complexes in V-6III type. Propylene glycol did not create complex with amylose but promoted the formation of amylose-carvacrol complexes in the presence or not of konjac glucomannan. Differential scanning calorimetry study showed that low concentrations of konjac glucomannan (0.2%) seemed to disturb the establishment of amylose-carvacrol complexes. Results showed that the time of adding carvacrol to starch dispersions, i.e. prior or after the heating of suspensions, and the presence of konjac glucomannan influenced the location of carvacrol in the different phases. These results allow understanding how the location and the amounts of ligands in the biphasic suspension influence the retention of carvacrol. By comparing the distribution of carvacrol on a period of 24H, the trapping by amylose was shown amplified with time. This demonstrated that the implementation of amylose - carvacrol interactions was highly dependent on the experimental conditions and on time.
