Effects of addition amounts of crosslinker and etherifying agent on properties of modified waxy corn starch

Abstract

Objective: This study aimed to control the degree of crosslinking and etherification in the preparation process of crosslinked hydroxypropyl starch and improve the product performance. Methods: Waxy corn starch was used as a raw material to prepare the composite modified starch （hydroxypropyl distarch phosphate, HDP） under alkaline conditions, during which process sodium trimetaphosphate （STMP） and propylene oxide （PO） was used as the cross-linker and etherifying agent, respectively. The effects of the addition level of STMP and PO on the properties of the Brabender viscosity behavior, transparency and freeze-thaw stability of waxy corn starch were investigated. Results: Combined with the preliminary laboratory exploration and the optimization of this study, a HDP with improved thermal stability, transparency and freeze-thaw stability and lowered gelatinization temperature was obtained. The preparation conditions of HDP were as follows: in the case that the amount of sodium trimetaphosphate was 0.30 g/100 g and cross-linking reaction time was 45 minutes, and the amount of propylene oxide added was 6 mL/100 g and the etherification time was 90 minutes. Conclusion: Compared to raw waxy corn starch, the cross-linked and etherified starches with decreased gelatinization temperature and improved freeze-thaw stability, thermal stability and gelling properties are observed.

Keywords

• waxy corn starch
• crosslinking
• etherification
• viscosity
• thermal stability