Core-Shell structural regulation and freshness indicating-keeping functions of starch-based Fiber membrane and its application in fresh-cut kiwifruits.

Fresh-cut fruits are highly susceptible to microbial contamination, leading to nutrient degradation, spoilage, and food safety risks. Using blueberry anthocyanins (BA) as an indicator, 1-methylcyclopropene (1-MCP) as a preservative, and acetylated starch (AS) with pullulan (PUL) as matrices, a core-shell structural fiber membrane with indication and freshness-keeping functions was prepared via coaxial electrospinning technology. The hydrophobicity, mechanical properties, morphological characteristics, and freshness-keeping rate of the fiber membrane were investigated. It was found that the hydrophobicity of the fiber membrane increased with the increase in the degree of starch esterification. The mechanical properties of the fiber membrane prepared with AS (DS2.0)/PUL ratio of 15:5 were the best. The proportion of core-shell fibers was positively correlated with the pushing speed ratio of coaxial electrospinning. When the amount of edible oil was 70 %, the proportion of core-shell fibers was the highest at 52.90 %. The addition of 2 % BA to the shell-layer spinning solution resulted in the optimal pH responsiveness, where the color change reaction within the pH range of 5-7 can be distinguished by the naked eye. GC/MS results demonstrated successful encapsulation of 1-MCP in the core layer and its sustainable-release for 96 h. The functional fiber membrane treatment significantly slowed the degradation of soluble solids and vitamin C, reduced total phenolic consumption, and extended the shelf life of fresh-cut kiwifruit by 66 % during storage. This study provides theoretical support for the application of this functional fiber membrane in fresh-keeping and visual freshness monitoring of fresh-cut fruits.