On the water-sorption properties of pectin

In this work we investigate the water-sorption isotherms of three types of pectins (from apple, citrus and sunflower) at 25 °C, 35 °C and 45 °C through the classical gravimetric method. The experimental data are treated with BET and GAB model equations for finding the monolayer moisture content Xw,a, BET and Guggenheim constants. The investigated pectins were characterized by their X-ray and infrared spectra and an attempt was made to correlate between their water-sorption properties and their molecular structure and crystal organization.