School of Food Science and Technology, Henan University of Technology, Zhengzhou, China.
J Sci Food Agric. 2019 Aug 15;99(10):4725-4730. doi: 10.1002/jsfa.9713. Epub 2019 Apr 30.
Since microcapsule technology has a good protective effect on unstable bioactive substances, many studies have focused on exploring the best technical conditions for forming microcapsules. Modified starch is a microcapsule wall material with good emulsifying and film-forming properties. The objective of this work was to study the creep-recovery behavior of modified starch pastes for various creep time, shear stress and temperature. Furthermore, the effect of creep-recovery behavior on the morphology of microcapsules made of the modified starch was investigated.
The maximum creep compliance (J ), instantaneous compliance (J ) and retardation compliance (J ) of modified starch increased proportionally with increasing creep time and shear stress but decreased with increasing temperature. The Newtonian viscosity (η ) increased with increasing creep time and temperature but decreased with increasing shear stress. The recovery rate of the modified starch pastes varied from 0.92 to 33.68% in the creep-recovery test conditions. Creep-recovery data could be well explained by a four-parameter Burgers model (R > 0.918).
Modified starch pastes exhibited time-, stress- and temperature-dependent creep-recovery behavior. The J values of modified starch pastes were low(<0.20 Pa ) and the η values high (>3.5 × 10 Pa s) for all test conditions. The results revealed the modified starch pastes had a good rigid network structure to resist deformation but recovery was difficult once deformation occurred. Microcapsules produced using the modified starch exhibited a small deformation with regular spheres and some dents, consistent with the results of creep-recovery tests. © 2019 Society of Chemical Industry.
由于微胶囊技术对不稳定的生物活性物质具有良好的保护作用，因此许多研究都集中在探索形成微胶囊的最佳技术条件上。改性淀粉是一种具有良好乳化和成膜性能的微胶囊壁材料。本工作旨在研究不同的应变时间、剪切应力和温度下，改性淀粉糊的蠕变恢复行为。此外，还研究了蠕变恢复行为对由改性淀粉制成的微胶囊形态的影响。
改性淀粉的最大蠕变柔量（J ）、瞬时柔量（J ）和延迟柔量（J ）随蠕变时间和剪切应力的增加而呈比例增加，但随温度的升高而降低。牛顿粘度（η）随蠕变时间和温度的增加而增加，随剪切应力的增加而降低。在蠕变恢复试验条件下，改性淀粉糊的恢复率在 0.92%至 33.68%之间变化。蠕变恢复数据可以用四参数 Burgers 模型很好地解释（R > 0.918）。
改性淀粉糊表现出时间、应力和温度依赖性的蠕变恢复行为。在所有测试条件下，改性淀粉糊的 J 值均较低（<0.20 Pa），η值较高（>3.5×10 Pa s）。结果表明，改性淀粉糊具有良好的刚性网络结构，可抵抗变形，但一旦发生变形，恢复就很困难。使用改性淀粉生产的微胶囊变形较小，呈规则球体，有一些凹痕，与蠕变恢复试验结果一致。 © 2019 英国化学学会。
