Near infrared spectroscopy: a new tool for studying physical and chemical properties of polysaccharide gels

This study explored the use of short-wavelength near infrared spectroscopy (SW-NIR, 600–1100 nm) to characterize gellan gel, a polysaccharide gel. SW-NIR can classify commercial low acyl (LA) and high acyl (HA) gellan gel mixtures and predict the ratio of LA and HA gellan in a gel mixture (R2=0.93, standard error of prediction=9.19%). In addition, SW-NIR methods can classify LA gellan gels based upon storage temperature (4 and 22 °C) and can determine gelling temperature of LA gellan gel. SW-NIR methods demonstrated that the structure of LA gellan gel (4 mM Ca++) remained stable under room temperature following gelation (5–72 h).