Determination of the Critical Micelle Concentration of Gelatin, ι-Carrageenan, Pectin, Gellan Gum and Xanthan Gum by Mid Infrared Spectroscopy Among Other Techniques

Critical micelle concentration (CMC) is the main physico-chemical parameter to be determined for surfactants due to its impact on surface activity and self-assembled aggregation. The aim of the present study is to determine CMC at 40 °C of gelatin, ι-carrageenan, pectin, gellan gum and xanthan gum by using different analytical techniques, particularly mid-infrared (MIR) spectroscopy as a rapid technique. The CMC values obtained for each hydrocolloid were relatively identical regardless of the applied technique: rheometer, conductimetry and automatic drop tensiometer (tracker). Indeed, CMC values of 55.16 g/L, 14 g/L, 6.04 g/L, 7 g/L and 3.48 g/L were obtained, respectively, for gelatin, ι-carrageenan, pectin, gellan gum and xanthan gum by using the surface tension method (tracker). Similar results were obtained for MIR spectroscopy since CMC values of 70 g/L, 15 g/L, 7 g/L, 5 g/L and 6 g/L were observed, respectively, for gelatin, ι-carrageenan, pectin, gellan gum and xanthan gum. The results presented here clearly demonstrate that it is possible to use MIR spectroscopy as a rapid analytical technique for the CMC determination of the investigated hydrocolloids.