Effect of Cross-linking with Epichlorohydrin on the Properties of Cassava (Manihot esculenta Crantz) Starch.

Alummoottil N. Jyothi; Subramoney N. Moorthy; Kallikat N. Rajasekharan

Cassava starch was cross-linked with epichlorohydrin (EPI) at 45°C for 2 h in three different media which include water, water in the presence of a phase transfer catalyst (PTC) and N,N-dimethylformamide (DMF). The products were characterized by determining their physicochemical, thermal and retrogradation properties. In aqueous medium, the use of a PTC, tetrabutylammonium bromide (TBAB) produced derivatives with higher degree of cross-linking than those prepared without the use of the catalyst. The degree of cross-linking was found to be higher using the same concentration of EPI when the reaction was carried out in DMF. At low levels of cross-linking, the peak viscosity of the cross-linked starches increased in comparison to that of the native starch. With increasing degree of cross-linking, the peak viscosity showed a significant reduction. The swelling volume, solubility and light transmittance of the starch pastes were lower for the modified starches. The cross-linked starches showed slightly reduced values for the gelatinization temperatures, Tonset, Tpeak and Tend. The enthalpy of gelatinization of the modified starches increased with increase in the degree of cross-linking. The modified starches exhibited higher water-binding capacities (WBC) than the native starch; but with increase in the degree of cross-linking, there was a gradual decrease in WBC. The in vitro alpha amylase digestibility of the modified starches decreased gradually with increase in the level of cross-linking.

MANIHOT; EUPHORBIACEAE; STARCH; PHASE-transfer catalysis

Starch / Staerke, 2006, Vol 58, Issue 6, p292

0038-9056

Academic Journal

10.1002/star.200500468