Preparation of composite hydrogel with mechanical stability and temperature response for tea polyphenol release

The method of adding additives at once not only increases costs, but also poses a risk of excessive consumption. Therefore, the slow-release technology was employed for improving the utilization efficiency and edible safety of additives in this work. The poly (N-isopropylacrylamide) (PNIPAM) and polylactic acid (PLA) composite hydrogels with sheath-core structure were fabricated by in-situ spinning method. The mechanical bearing capacity of PNIPAM hydrogel was improved by controlling the structure of PLA electrospun fiber membrane. The results showed that the compression resistance of the samples coated with PLA was increased 931 % at 50 % deformation. In addition, the surface wettability of samples was studied to ensure the stable water permeability. The composite hydrogel was used for the sustained release of tea polyphenol (TP) antioxidant. The release effect of TP at different temperatures, and radical scavenging effect of 2, 2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2-Phenyl-4,4,5,5-tetraMethyliMidazoline-3-oxide-1-oxyl) (PTIO) were investigated. It was found that the release rate for TP could reach to 77.8 % at 30 °C. The radical clearance rates of ABTS and PTIO were 99.2 % and 46.6 %, respectively. This work provides effective ideas for the use of antioxidants in food preservation processes.