On the gelation of mungbean starch and its composites

Light microscopy and the concentration dependence of the elastic modulus of mungbean starch (MB) gel indicate that the gelation of MB is mainly governed by a close-packing mechanism. The mechanical property of the entire network is influenced by the strength of swollen amylose-rich discrete gel particles rather than the surrounding matrix. However, when the physicochemical properties of the surrounding matrix is altered by the presence of flour fillers possessing lower gelatinisation temperature and enthalpy, both the stress-related and strain-related parameters of MB-based mixed flour gels were reduced (P < 0.05). Addition of iota-carrageenan (1.0% w/v), in both the absence and presence of calcium lactate (0-20 mM), further reduced both the stress-related and strain-related parameters of the composite gels. This study shows the detrimental effect of the anionic hydrocolloids and divalent cation addition on the mechanical properties of a composite structure stabilised by close-packing mechanism.