Department of Food Engineering and Technology, Tezpur University, Assam 784028, India.
Department of Food Engineering and Technology, Tezpur University, Assam 784028, India.
Int J Biol Macromol. 2019 May 15;129:1006-1014. doi: 10.1016/j.ijbiomac.2019.02.104. Epub 2019 Feb 19.
Dual modification of barley starch using annealing and hydroxypropylation was carried out. The native starch was first annealed in single step and dual step. After that, hydroxypropylation of the native, single step and dual step annealed starches were performed. The properties of native and modified starches were then investigated. Relative crystallinity of the modified starches decreased with level of hydroxypropylation and increased on annealing. Swelling, solubility, freeze-thaw stability and paste viscosities increased on hydroxypropylation and decreased with annealing. Paste clarity increased on both annealing and hydroxypropylation. Freeze-thaw stability, paste clarity and final viscosity were higher for dual modified barley starches modified by combining annealing and hydroxypropylation. Rheological studies revealed pseudoplastic nature of the starches. The flow behaviour index was found to decrease with level of hydoxypropylation for native starch, but increased for the dual modified starches. Dual modification of barley starch by combining dual step annealing with hydroxypropylation significantly improved the properties of native starch.
采用退火和羟丙基化双重修饰大麦淀粉。首先对天然淀粉进行单步和双步退火，然后对天然淀粉、单步和双步退火淀粉进行羟丙基化。然后研究了天然淀粉和改性淀粉的性质。改性淀粉的相对结晶度随羟丙基化水平的增加而降低，随退火的增加而增加。随着羟丙基化的增加，淀粉的溶胀性、溶解度、冻融稳定性和糊粘度降低，而随着退火的增加，糊粘度降低。在退火和羟丙基化作用下，糊的透明度均增加。通过将退火和羟丙基化相结合对双改性大麦淀粉进行改性，可显著提高淀粉的冻融稳定性、糊的透明度和最终粘度。流变学研究表明，淀粉具有假塑性。对于天然淀粉，发现流变性指数随羟丙基化水平的增加而降低，但对于双改性淀粉则增加。通过将双步退火与羟丙基化相结合对大麦淀粉进行双重修饰，可显著改善天然淀粉的性能。
