Department of Food Science and Technology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
Glyn O. Phillips Hydrocolloids Research Centre, School of Food and Biological Engineering, Hubei University of Technology, Wuhan 430068, PR China.
Adv Colloid Interface Sci. 2020 Nov;285:102278. doi: 10.1016/j.cis.2020.102278. Epub 2020 Sep 23.
Enhancement on the mechanical properties of hydrogels leads to a wider range of their applications in various fields. Therefore, there has been a great interest recently for developing new strategies to reinforce hydrogels. Moreover, food gels must be edible in terms of both raw materials and production. This paper reviews innovative techniques such as particle/fiber-reinforced hydrogel, double network, dual crosslinking, freeze-thaw cycles, physical conditioning and soaking methods to improve the mechanical properties of hydrogels. Additionally, their fundamental mechanisms, advantages and disadvantages have been discussed. Important biopolymers that have been employed for these strategies and also their potentials in food applications have been summarized. The general mechanism of these strategies is based on increasing the degree of crosslinking between interacting polymers in hydrogels. These links can be formed by adding fillers (oil droplets or fibers in filled gels) or cross-linkers (regarding double network and soaking method) and also by condensation or alignment of the biopolymers (freeze-thaw cycle and physical conditioning) in the gel network. The properties of particle/fiber-reinforced hydrogels extremely depend on the filler, gel matrix and the interaction between them. In freeze-thaw cycles and physical conditioning methods, it is possible to form new links in the gel network without adding any cross-linkers or fillers. It is expected that the utilization of gels will get broader and more varied in food industries by using these strategies.
水凝胶的机械性能增强使其在各个领域的应用范围更广。因此，最近人们非常有兴趣开发新的策略来增强水凝胶。此外，食品凝胶在原材料和生产方面都必须是可食用的。本文综述了一些创新性技术，如颗粒/纤维增强水凝胶、双重网络、双重交联、冻融循环、物理调理和浸泡法，以改善水凝胶的机械性能。此外，还讨论了它们的基本机制、优缺点。总结了用于这些策略的重要生物聚合物及其在食品应用中的潜力。这些策略的一般机制是基于增加水凝胶中相互作用聚合物之间的交联程度。这些键可以通过添加填料（填充凝胶中的油滴或纤维）或交联剂（关于双重网络和浸泡法）以及通过凝胶网络中生物聚合物的缩合或取向（冻融循环和物理调理）来形成。颗粒/纤维增强水凝胶的性能极大地取决于填料、凝胶基质和它们之间的相互作用。在冻融循环和物理调理方法中，无需添加任何交联剂或填料即可在凝胶网络中形成新的键。预计通过使用这些策略，凝胶在食品工业中的应用将变得更加广泛和多样化。
