退火处理对葛根淀粉老化特性和质构特性的影响

Effects of annealing time on retrogradation and texture properties of Pueraria lobata(Willd.) starch

采用差式量热扫描仪(DSC)、低场核磁共振分析仪和质构分析仪研究退火处理对葛根淀粉老化过程中水分迁移、老化特性和质构特性的影响。结果表明,退火处理会使葛根淀粉在老化过程中的水分子相对含量降低;退火时间对葛根淀粉老化度的影响较为明显,随着退火时间的延长,葛根淀粉的糊化焓增加,老化焓降低,老化度降低,当退火时间达到24 h时,葛根淀粉老化1 d后的老化度从原葛根淀粉的32.95%降到19.58%,老化10 d后的老化度从37.42%降到19.46%;原葛根淀粉凝胶和退火处理葛根淀粉凝胶的凝胶强度随着时间的延长而增大,当退火时间达到24 h时,老化1 d后的凝胶强度从原葛根淀粉的27.34增加到48.44,老化10 d后的凝胶强度从72.11增加到76.45,弹性则随着时间的延长而减小。

The effects of annealing time on moisture distribution, retrogradation and texture properties of Pueraria lobata （Willd.） starch were investigated using differential scanning calorimetry （DSC）, low field NMR and texture analyzer. The results indicated that the relative content of water molecules in Pueraria lobata （Willd.） starch in the process of retrogradation decreased after annealing. Annealing treatment increased gelatinization en- thalpy of the gelatinized starch and decreased the aging enthalpy and retrogradation degree. When the annealing time was 24 h, the retrogradation degree ofPueraria lobata （Willd.） starch decreased from 32.95 % to 19.58 % stored after one day and decreased from 37.42 % to 19.46 % stored after 10 days. The gel strength of the annealed starch gel was higher than that of the native one. When the annealing time was 24 h, the gel strength of Pueraria lobata （Willd.） starch increased from 27.34 to 48.44 stored after 1 day and it increased from 72.11 to 76.45 stored after 10 days. However, the elasticity of the annealed starch was lower than that of the native one.