Investigation of dual modification on physicochemica morphological, thermal, pasting, and retrogradation characteristics of sago starch

The aim of this study was to evaluate the characteristics of dually modified sago starch by acid hydrolysis (AH)-hydroxypropylation (HP). For this purpose, sago starch was modified with the combination by AH (5-20 h hydrolysis times) followed by HP (5%-25% ratio of propylene oxide) processes. The results showed that the dual modification of the sago starch structure didn't have a significant effect on the size of starch granules, and the granule size was in the range of 0,005-0,151 pm; however, the pasting properties and the glass transition temperature decreased significantly (p < .05). Increasing the level of propylene oxide from 5% to 25% caused a significant increase in the substitution degree (DS) and swelling ability of starches and reduced the syneresis, while with increasing acid hydrolysis time from 5 h to 20 h, starch swelling decreased and syneresis increased (p < .05). AH process at high hydrolysis times (20 h) increased the gelatinization temperatures and decreased retrogradation temperatures. Increasing the level of propylene oxide in both single and dual modification reduced the temperatures and enthalpy of gelatinization and retrogradation of sago starch. In summary, dually modified sago starch has a great potential to use in specific food products such as frozen dough or frozen bakery products.

Automated summary

This study evaluated the characteristics of dually modified sago starch by acid hydrolysis (AH)-hydroxypropylation (HP). The dual modification didn't affect the size of starch granules significantly, but decreased the pasting properties and the glass transition temperature. Increasing the level of propylene oxide increased the substitution degree and swelling ability of starches, and reduced syneresis. Increasing acid hydrolysis time decreased starch swelling and increased syneresis. High hydrolysis time increased gelatinization temperatures and decreased retrogradation temperatures. Increasing the level of propylene oxide reduced the temperatures and enthalpy of gelatinization and retrogradation of sago starch. Dually modified sago starch has potential applications in specific food products.