Effect of cross-linking and esterification on hygroscopicity and surface activity of cassava maltodextrins

The hygroscopicities of cassava maltodextrins, namely cassava maltodextrin (CMD), cassava cross-linked maltodextrin (CCMD), cassava octenyl succinic maltodextrin (COMD) and cassava cross-linked octenyl succinic maltodextrin (CCOMD), gradually increased as the dextrose equivalent (DE) and relative humidity (RH) increased. The hygroscopicities of four types of maltodextrins, with DE 10.2, were 13.42%, 9.89%, 11.80% and 8.91%, respectively, at 25 °C and RH 85%. It was observed that cross-linking and esterification decreased hygroscopicities by 26.5% and 12.1%, whereas the combination of them reduced it by 33.7%. The surface activities of cassava maltodextrins were estimated from the surface tension measurement. At 5%, the air–water surface tensions of CMD, CCMD, COMD and CCOMD solutions were 67.24 mN/m, 64.61 mN/m, 52.93 mN/m and 52.21 mN/m, respectively. The influence of esterification on surface activity was more effective than that of cross-linking.