A Hydrogel with Sustained Release of 1-MCP Affects the Fruit Quality and Disease Resistance of Postharvest Strawberry

In recent years, extensive research has centered on the application of 1-methylcyclopropene (1-MCP) in fruit preservation, with a predominant focus on climacteric fruits. However, the development of efficient sustained-release products remains insufficient, and the effects of 1-MCP on the quality of non-climacteric fruits such as strawberry in postharvest are not fully understood. This research investigates the creation of a 1-MCP hydrogel-based controlled release product for strawberry preservation. The hydrogel system used in the preservative was synthesized using hydroxyethyl acrylate (HEA) and acrylic acid (AA) as monomers, with polyethylene glycol diacrylate (PEGDA) serving as a cross-linking agent. 1-MCP sustained-release hydrogel, which was referred to as 1-MCP Hydrogel, was prepared by wrapping 1-MCP powder in a porous water gel system in an aqueous solvent system and initiated by diphenyl phosphorus oxide (TPO). The 1-MCP Hydrogel was applied to the preservation of strawberry stored at room temperature. The results showed that the 1-MCP Hydrogel had excellent 1-MCP sustained release performance, and could release 1-MCP evenly and slowly. Its release rate was 7% of the 1-MCP powder group and 3% of the 1-MCP powder solution group, respectively, at 12 h, achieving a long-term effective release. Fruit experiments showed that the 1-MCP Hydrogel group maintained a lower weight loss rate and decay rate, which were 20% and 21% lower than the control group on day 6, respectively. In addition, 1-MCP Hydrogel maintained better fruit color, higher hardness, soluble solids content (TSS), and titratable acid content (TA). On day 2, the a^* value, b^* value and L^* value of the experimental group were 11%, 11%, and 6% higher than the control group, respectively. The hardness, TSS, and TA on day 6 were 21%, 15%, and 18% higher than the control group, respectively. To sum up, 1-MCP Hydrogel has multiple functions, such as the sustained release of 1-MCP, improving fruit quality. It is also convenient to prepare and can be used in the postharvest preservation of strawberries and potentially other fruit.