Triggered release of hexanal from an imidazolidine precursor encapsulated in poly(lactic acid) and ethylcellulose carriers

Hexanal is a naturally occurring aliphatic aldehyde with antimicrobial and phospholipase D inhibition properties, useful for post-harvest preservation of fresh fruits and produce. However, hexanal is highly volatile and susceptible to oxidative degradation. To overcome these issues, a precursor was synthesized and entrapped in poly(lactic acid) (PLA) fiber or ethylcellulose (EC) particulate carriers. The precursor was synthesized through nucleophilic addition of hexanal to N,N'-dibenzylethane-1,2-diamine to form 1,3-dibenzylethane-2-pentyl imidazolidine-a stable hexanal precursor compound. H-1 and C-13 NMR analyses confirmed the formation of heterocyclic ring structure in the precursor. SEM analysis revealed that the precursor was dispersed homogeneously within the PLA and EC carriers by electrospinning or electrospraying processes, respectively. The release of hexanal was triggered by the hydrolysis of the imidazolidine compound at 5, 25, and 45 A degrees C, via the addition of 0.1 N citric acid to the precursor-loaded carriers. The citric acid solution resulted in significantly (p < 0.05) higher amounts and rates of hexanal released in PLA than EC, but both carriers had similar activation energies of hexanal release. FTIR analysis did not detect specific interactions between the precursor and the polymers. The hexanal precursor developed here potentially can be used as a component of active packaging to deliver hexanal and other aldehydes to enhance storage stability of fresh produce.