Effects of different ratios of water and glycerol on the physicochemical properties of starch-based straws

This study aimed to assess the effects of different ratios of water and glycerol on the physicochemical properties of starch-based straws (SBS) and explore their plasticising mechanism. X-ray diffraction analysis revealed that the V -type complex formation was influenced by adjusting the ratio of glycerol and water. The extruded samples exhibited lower water content (4.72–7.65 %) than those of native starch (12.39 %). The change in hydrogen bond interactions among water, starch and glycerol was the main reason for the difference in the performance. The glass transition temperature (T g ’) ranged from −6.2 to −9.1 °C for the SBS with glycerol, while the T g ’ values was −2.7 °C for the native starch. The sample with 15 % glycerol and 5 % water showed the highest maximum decomposition temperature (323.91 °C) and contact angle (72.07°) among all of the analysed SBS. The E b values of glycerol-containing samples (136.13–308.13 N/cm) were lower than that of the water-containing samples (291.26–356.53 N/cm).