Electrospinning PCL-CA packaging membranes with transmittance response to ethanol for monitoring grape freshness.

In recent years, there has been an increasing focus on the development of active films for monitoring and maintaining food freshness. However, its further functional diversification remains highly desirable. In this study, the active polycaprolactone (PCL) based membranes loaded with carvacrol (CA) are fabricated via electrospinning technique for grape preservation. Upon touching with ethanol exudate, the resulting membrane is capable of changing from opaque to a reversible transparent packaging (RTP) through interfibrillar fusion during food storage. The RTP exhibits good reusability with light transparency above 80 % after 10 cycles. CA is well-dispersed in the fiber matrix by hydrogen bonding and enriching the membrane with strong antibacterial activity. Furthermore, the release of CA from film matrix is well controlled and predominantly governed by Fickian diffusion. In addition to freshness monitoring, PCL-CA15 can effectively extend the shelf life of grape by about 4 days at 25 °C.