Study on r-Amylase Hydrolysis of Potato Amylopectin by a Quartz Crystal Microbalance

Potato amylopectin with phosphate groups was immobilized on a quartz crystal microbalance with dissipation monitoring (QCMD) using the attractive interaction between opposite charges, and enzymatic starch hydrolysis was monitored directly. Poly(L-lysine) (PLL) proved to be an appropriate cationic linker between the QCMD silica sensor and potato amylopectin. Increased mass and
dissipation were observed when amylopectin was adsorbed onto the PLL layer and reversed when R-amylase was added. The effect of chitosan with cationic property on the hydrolysis of amylopectin was studied. Chitosan was observed to be adsorbed onto the amylopectin surface and to suppress hydrolysis by R-amylase. The formation of alternating layers of amylopectin and chitosan was
monitored by QCMD. Amylopectin-chitosan trilayers increased resistance to digestion by R-amylase compared to one layer and to control without chitosan.