Hydrogel pads loaded with essential oil contribute to maintaining blueberry quality after transportation

Immediate shipment has become a new trend in online blueberry sales, leaving little to no time for postharvest treatment. To address this, a novel approach was developed, enabling blueberries to be shipped without additional treatment after harvest. This was achieved using terpinen-4-ol (T4O)-loaded PVA-PVP hydrogel pads (THPP), which maintained blueberry quality during transportation and subsequent storage. In this study, varying amounts of T4O were incorporated into THPP pads to evaluate their physical properties, antimicrobial activity, and preservation effects during blueberry simulated transportation. Then, the structural characterization of the optimal THPP pad was analyzed. The results showed that as the T4O concentration increased, the elasticity, water-holding capacity, and antimicrobial efficacy of the pads improved. While it was not the same in blueberry simulation transportation experiment, where 1 % THPP exhibited the best preservation effects among all treatments. Compared to the control group, it delayed the incidence of blueberries by 6 d, showing higher firmness by 67.3 %, and higher anthocyanin content by 42.1 %. Based on these three aspects, 1 % THPP was identified as the optimal pad. Structural analysis of the 1 % THPP showed that T4O cross-linked with PVA-PVP hydrogel (HPP) via hydrogen bonds, resulting in a more uniform structure and improved thermal stability of HPP.